Description of hardware operation
---------------------------------
The core AMD PMU has a 4-bit wide per-cycle increment for each
performance monitor counter. That works for most events, but
now with AMD Family 17h and above processors, some events can
occur more than 15 times in a cycle. Those events are called
"Large Increment per Cycle" events. In order to count these
events, two adjacent h/w PMCs get their count signals merged
to form 8 bits per cycle total. In addition, the PERF_CTR count
registers are merged to be able to count up to 64 bits.
Normally, events like instructions retired, get programmed on a single
counter like so:
PERF_CTL0 (MSR 0xc0010200) 0x000000000053ff0c # event 0x0c, umask 0xff
PERF_CTR0 (MSR 0xc0010201) 0x0000800000000001 # r/w 48-bit count
The next counter at MSRs 0xc0010202-3 remains unused, or can be used
independently to count something else.
When counting Large Increment per Cycle events, such as FLOPs,
however, we now have to reserve the next counter and program the
PERF_CTL (config) register with the Merge event (0xFFF), like so:
PERF_CTL0 (msr 0xc0010200) 0x000000000053ff03 # FLOPs event, umask 0xff
PERF_CTR0 (msr 0xc0010201) 0x0000800000000001 # rd 64-bit cnt, wr lo 48b
PERF_CTL1 (msr 0xc0010202) 0x0000000f004000ff # Merge event, enable bit
PERF_CTR1 (msr 0xc0010203) 0x0000000000000000 # wr hi 16-bits count
The count is widened from the normal 48-bits to 64 bits by having the
second counter carry the higher 16 bits of the count in its lower 16
bits of its counter register.
The odd counter, e.g., PERF_CTL1, is programmed with the enabled Merge
event before the even counter, PERF_CTL0.
The Large Increment feature is available starting with Family 17h.
For more details, search any Family 17h PPR for the "Large Increment
per Cycle Events" section, e.g., section 2.1.15.3 on p. 173 in this
version:
https://www.amd.com/system/files/TechDocs/56176_ppr_Family_17h_Model_71h_B0_pub_Rev_3.06.zip
Description of software operation
---------------------------------
The following steps are taken in order to support reserving and
enabling the extra counter for Large Increment per Cycle events:
1. In the main x86 scheduler, we reduce the number of available
counters by the number of Large Increment per Cycle events being
scheduled, tracked by a new cpuc variable 'n_pair' and a new
amd_put_event_constraints_f17h(). This improves the counter
scheduler success rate.
2. In perf_assign_events(), if a counter is assigned to a Large
Increment event, we increment the current counter variable, so the
counter used for the Merge event is removed from assignment
consideration by upcoming event assignments.
3. In find_counter(), if a counter has been found for the Large
Increment event, we set the next counter as used, to prevent other
events from using it.
4. We perform steps 2 & 3 also in the x86 scheduler fastpath, i.e.,
we add Merge event accounting to the existing used_mask logic.
5. Finally, we add on the programming of Merge event to the
neighbouring PMC counters in the counter enable/disable{_all}
code paths.
Currently, software does not support a single PMU with mixed 48- and
64-bit counting, so Large increment event counts are limited to 48
bits. In set_period, we zero-out the upper 16 bits of the count, so
the hardware doesn't copy them to the even counter's higher bits.
Simple invocation example showing counting 8 FLOPs per 256-bit/%ymm
vaddps instruction executed in a loop 100 million times:
perf stat -e cpu/fp_ret_sse_avx_ops.all/,cpu/instructions/ <workload>
Performance counter stats for '<workload>':
800,000,000 cpu/fp_ret_sse_avx_ops.all/u
300,042,101 cpu/instructions/u
Prior to this patch, the reported SSE/AVX FLOPs retired count would
be wrong.
[peterz: lots of renames and edits to the code]
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
AMD Family 17h processors and above gain support for Large Increment
per Cycle events. Unfortunately there is no CPUID or equivalent bit
that indicates whether the feature exists or not, so we continue to
determine eligibility based on a CPU family number comparison.
For Large Increment per Cycle events, we add a f17h-and-compatibles
get_event_constraints_f17h() that returns an even counter bitmask:
Large Increment per Cycle events can only be placed on PMCs 0, 2,
and 4 out of the currently available 0-5. The only currently
public event that requires this feature to report valid counts
is PMCx003 "Retired SSE/AVX Operations".
Note that the CPU family logic in amd_core_pmu_init() is changed
so as to be able to selectively add initialization for features
available in ranges of backward-compatible CPU families. This
Large Increment per Cycle feature is expected to be retained
in future families.
A side-effect of assigning a new get_constraints function for f17h
disables calling the old (prior to f15h) amd_get_event_constraints
implementation left enabled by commit e40ed1542d ("perf/x86: Add perf
support for AMD family-17h processors"), which is no longer
necessary since those North Bridge event codes are obsoleted.
Also fix a spelling mistake whilst in the area (calulating ->
calculating).
Fixes: e40ed1542d ("perf/x86: Add perf support for AMD family-17h processors")
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20191114183720.19887-2-kim.phillips@amd.com
Implement intel_pmu_lbr_swap_task_ctx() method updating counters
of the events that requested LBR callstack data on a sample.
The counter can be zero for the case when task context belongs to
a thread that has just come from a block on a futex and the context
contains saved (lbr_stack_state == LBR_VALID) LBR register values.
For the values to be restored at LBR registers on the next thread's
switch-in event it swaps the counter value with the one that is
expected to be non zero at the previous equivalent task perf event
context.
Swap operation type ensures the previous task perf event context
stays consistent with the amount of events that requested LBR
callstack data on a sample.
Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: https://lkml.kernel.org/r/261ac742-9022-c3f4-5885-1eae7415b091@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Declare swap_task_ctx() methods at the generic and x86 specific
pmu types to bridge calls to platform specific PMU code on optimized
context switch path between equivalent task perf event contexts.
Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: https://lkml.kernel.org/r/9a0aa84a-f062-9b64-3133-373658550c4b@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
If PEBS declares ability to output its data to Intel PT stream, use the
aux_output attribute bit to enable PEBS data output to PT. This requires
a PT event to be present and scheduled in the same context. Unlike the
DS area, the kernel does not extract PEBS records from the PT stream to
generate corresponding records in the perf stream, because that would
require real time in-kernel PT decoding, which is not feasible. The PMI,
however, can still be used.
The output setting is per-CPU, so all PEBS events must be either writing
to PT or to the DS area, therefore, in case of conflict, the conflicting
event will fail to schedule, allowing the rotation logic to alternate
between the PEBS->PT and PEBS->DS events.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: kan.liang@linux.intel.com
Link: https://lkml.kernel.org/r/20190806084606.4021-3-alexander.shishkin@linux.intel.com
We don't need pmu->pebs_no_xmm_regs anymore, the capabilities
PERF_PMU_CAP_EXTENDED_REGS can be used to check if XMM registers
collection is supported.
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: https://lkml.kernel.org/r/1559081314-9714-4-git-send-email-kan.liang@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Using the new pmu::update_attrs attribute group for default
attributes - freeze_on_smi, allow_tsx_force_abort.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190512155518.21468-10-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Using the new pmu::update_attrs attribute group for
"caps" directory.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190512155518.21468-7-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Using the new pmu::update_attrs attribute group to
create detected events for x86_pmu.
Moving the topdown/memory/tsx attributes to separate
attribute groups with specific is_visible functions.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190512155518.21468-5-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
On Intel Westmere, a cmdline as follows:
$ perf record -e cpu/event=0xc4,umask=0x2,name=br_inst_retired.near_call/p ....
was failing. Yet the event+ umask support PEBS.
It turns out this is due to a bug in the the PEBS event constraint table for
westmere. All forms of BR_INST_RETIRED.* support PEBS. Therefore the constraint
mask should ignore the umask. The name of the macro INTEL_FLAGS_EVENT_CONSTRAINT()
hint that this is the case but it was not. That macros was checking both the
event code and event umask. Therefore, it was only matching on 0x00c4.
There are code+umask macros, they all have *UEVENT*.
This bug fixes the issue by checking only the event code in the mask.
Both single and range version are modified.
Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: kan.liang@intel.com
Link: http://lkml.kernel.org/r/20190509214556.123493-1-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add Icelake core PMU perf code, including constraint tables and the main
enable code.
Icelake expanded the generic counters to always 8 even with HT on, but a
range of events cannot be scheduled on the extra 4 counters.
Add new constraint ranges to describe this to the scheduler.
The number of constraints that need to be checked is larger now than
with earlier CPUs.
At some point we may need a new data structure to look them up more
efficiently than with linear search. So far it still seems to be
acceptable however.
Icelake added a new fixed counter SLOTS. Full support for it is added
later in the patch series.
The cache events table is identical to Skylake.
Compare to PEBS instruction event on generic counter, fixed counter 0
has less skid. Force instruction:ppp always in fixed counter 0.
Originally-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Cc: jolsa@kernel.org
Link: https://lkml.kernel.org/r/20190402194509.2832-9-kan.liang@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Icelake extended the general counters to 8, even when SMT is enabled.
However only a (large) subset of the events can be used on all 8
counters.
The events that can or cannot be used on all counters are organized
in ranges.
A lot of scheduler constraints are required to handle all this.
To avoid blowing up the tables add event code ranges to the constraint
tables, and a new inline function to match them.
Originally-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> # developer hat on
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> # maintainer hat on
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Cc: jolsa@kernel.org
Link: https://lkml.kernel.org/r/20190402194509.2832-8-kan.liang@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
With adaptive PEBS the CPU can directly supply the LBR information,
so we don't need to read it again. But the LBRs still need to be
enabled. Add a special count to the cpuc that distinguishes these
two cases, and avoid reading the LBRs unnecessarily when PEBS is
active.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Cc: jolsa@kernel.org
Link: https://lkml.kernel.org/r/20190402194509.2832-7-kan.liang@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Adaptive PEBS is a new way to report PEBS sampling information. Instead
of a fixed size record for all PEBS events it allows to configure the
PEBS record to only include the information needed. Events can then opt
in to use such an extended record, or stay with a basic record which
only contains the IP.
The major new feature is to support LBRs in PEBS record.
Besides normal LBR, this allows (much faster) large PEBS, while still
supporting callstacks through callstack LBR. So essentially a lot of
profiling can now be done without frequent interrupts, dropping the
overhead significantly.
The main requirement still is to use a period, and not use frequency
mode, because frequency mode requires reevaluating the frequency on each
overflow.
The floating point state (XMM) is also supported, which allows efficient
profiling of FP function arguments.
Introduce specific drain function to handle variable length records.
Use a new callback to parse the new record format, and also handle the
STATUS field now being at a different offset.
Add code to set up the configuration register. Since there is only a
single register, all events either get the full super set of all events,
or only the basic record.
Originally-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Cc: jolsa@kernel.org
Link: https://lkml.kernel.org/r/20190402194509.2832-6-kan.liang@linux.intel.com
[ Renamed GPRS => GP. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Starting from Icelake, XMM registers can be collected in PEBS record.
But current code only output the pt_regs.
Add a new struct x86_perf_regs for both pt_regs and xmm_regs. The
xmm_regs will be used later to keep a pointer to PEBS record which has
XMM information.
XMM registers are 128 bit. To simplify the code, they are handled like
two different registers, which means setting two bits in the register
bitmap. This also allows only sampling the lower 64bit bits in XMM.
The index of XMM registers starts from 32. There are 16 XMM registers.
So all reserved space for regs are used. Remove REG_RESERVED.
Add PERF_REG_X86_XMM_MAX, which stands for the max number of all x86
regs including both GPRs and XMM.
Add REG_NOSUPPORT for 32bit to exclude unsupported registers.
Previous platforms can not collect XMM information in PEBS record.
Adding pebs_no_xmm_regs to indicate the unsupported platforms.
The common code still validates the supported registers. However, it
cannot check model specific registers, e.g. XMM. Add extra check in
x86_pmu_hw_config() to reject invalid config of regs_user and regs_intr.
The regs_user never supports XMM collection.
The regs_intr only supports XMM collection when sampling PEBS event on
icelake and later platforms.
Originally-by: Andi Kleen <ak@linux.intel.com>
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Cc: jolsa@kernel.org
Link: https://lkml.kernel.org/r/20190402194509.2832-3-kan.liang@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
PEBS_REGS used as mask for the supported registers for large PEBS.
However, the mask cannot filter the sample_regs_user/sample_regs_intr
correctly.
(1ULL << PERF_REG_X86_*) should be used to replace PERF_REG_X86_*, which
is only the index.
Rename PEBS_REGS to PEBS_GP_REGS, because the mask is only for general
purpose registers.
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Cc: jolsa@kernel.org
Fixes: 2fe1bc1f50 ("perf/x86: Enable free running PEBS for REGS_USER/INTR")
Link: https://lkml.kernel.org/r/20190402194509.2832-2-kan.liang@linux.intel.com
[ Renamed it to PEBS_GP_REGS - as 'GPRS' is used elsewhere ;-) ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The flag PERF_X86_EVENT_COMMITTED is used to find uncommitted events
for which to call put_event_constraint() when scheduling fails.
These are the newly added events to the list, and must form, per
definition, the tail of cpuc->event_list[]. By computing the list
index of the last successfull schedule, then iteration can start there
and the flag is redundant.
There are only 3 callers of x86_schedule_events(), notably:
- x86_pmu_add()
- x86_pmu_commit_txn()
- validate_group()
For x86_pmu_add(), cpuc->n_events isn't updated until after
schedule_events() succeeds, therefore cpuc->n_events points to the
desired index.
For x86_pmu_commit_txn(), cpuc->n_events is updated, but we can
trivially compute the desired value with cpuc->n_txn -- the number of
events added in this transaction.
For validate_group(), we can make the rule for x86_pmu_add() work by
simply setting cpuc->n_events to 0 before calling schedule_events().
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Stephane Eranian <eranian@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Guenter reported a build warning for CONFIG_CPU_SUP_INTEL=n:
> With allmodconfig-CONFIG_CPU_SUP_INTEL, this patch results in:
>
> In file included from arch/x86/events/amd/core.c:8:0:
> arch/x86/events/amd/../perf_event.h:1036:45: warning: ‘struct cpu_hw_event’ declared inside parameter list will not be visible outside of this definition or declaration
> static inline int intel_cpuc_prepare(struct cpu_hw_event *cpuc, int cpu)
While harmless (an unsed pointer is an unused pointer, no matter the type)
it needs fixing.
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Fixes: d01b1f96a8 ("perf/x86/intel: Make cpuc allocations consistent")
Link: http://lkml.kernel.org/r/20190315081410.GR5996@hirez.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 tsx fixes from Thomas Gleixner:
"This update provides kernel side handling for the TSX erratum of Intel
Skylake (and later) CPUs.
On these CPUs Intel Transactional Synchronization Extensions (TSX)
functions can result in unpredictable system behavior under certain
circumstances.
The issue is mitigated with an microcode update which utilizes
Performance Monitoring Counter (PMC) 3 when TSX functions are in use.
This mitigation is enabled unconditionally by the updated microcode.
As a consequence the usage of TSX functions can cause corrupted
performance monitoring results for events which utilize PMC3. The
corruption is silent on kernels which have no update for this issue.
This update makes the kernel aware of the PMC3 utilization by the
microcode:
The microcode offers a possibility to enforce TSX abort which prevents
the malfunction and frees up PMC3. The enforced TSX abort requires the
TSX using application to have a software fallback path implemented;
abort handlers which solely retry the transaction will fail over and
over.
The enforced TSX abort request is issued by the kernel when:
- enforced TSX abort is enabled (PMU attribute)
- A performance monitoring request needs PMC3
When PMC3 is not longer used by the kernel the TSX force abort request
is cleared.
The enforced TSX abort mechanism is enabled by default and can be
controlled by the administrator via the new PMU attribute
'allow_tsx_force_abort'. This attribute is only visible when updated
microcode is detected on affected systems. Writing '0' disables the
enforced TSX abort mechanism, '1' enables it.
As a result of disabling the enforced TSX abort mechanism, PMC3 is
permanentely unavailable for performance monitoring which can cause
performance monitoring requests to fail or switch to multiplexing
mode"
* branch 'x86-tsx-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/intel: Implement support for TSX Force Abort
x86: Add TSX Force Abort CPUID/MSR
perf/x86/intel: Generalize dynamic constraint creation
perf/x86/intel: Make cpuc allocations consistent
Skylake (and later) will receive a microcode update to address a TSX
errata. This microcode will, on execution of a TSX instruction
(speculative or not) use (clobber) PMC3. This update will also provide
a new MSR to change this behaviour along with a CPUID bit to enumerate
the presence of this new MSR.
When the MSR gets set; the microcode will no longer use PMC3 but will
Force Abort every TSX transaction (upon executing COMMIT).
When TSX Force Abort (TFA) is allowed (default); the MSR gets set when
PMC3 gets scheduled and cleared when, after scheduling, PMC3 is
unused.
When TFA is not allowed; clear PMC3 from all constraints such that it
will not get used.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The cpuc data structure allocation is different between fake and real
cpuc's; use the same code to init/free both.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Vince (and later on Ravi) reported crashes in the BTS code during
fuzzing with the following backtrace:
general protection fault: 0000 [#1] SMP PTI
...
RIP: 0010:perf_prepare_sample+0x8f/0x510
...
Call Trace:
<IRQ>
? intel_pmu_drain_bts_buffer+0x194/0x230
intel_pmu_drain_bts_buffer+0x160/0x230
? tick_nohz_irq_exit+0x31/0x40
? smp_call_function_single_interrupt+0x48/0xe0
? call_function_single_interrupt+0xf/0x20
? call_function_single_interrupt+0xa/0x20
? x86_schedule_events+0x1a0/0x2f0
? x86_pmu_commit_txn+0xb4/0x100
? find_busiest_group+0x47/0x5d0
? perf_event_set_state.part.42+0x12/0x50
? perf_mux_hrtimer_restart+0x40/0xb0
intel_pmu_disable_event+0xae/0x100
? intel_pmu_disable_event+0xae/0x100
x86_pmu_stop+0x7a/0xb0
x86_pmu_del+0x57/0x120
event_sched_out.isra.101+0x83/0x180
group_sched_out.part.103+0x57/0xe0
ctx_sched_out+0x188/0x240
ctx_resched+0xa8/0xd0
__perf_event_enable+0x193/0x1e0
event_function+0x8e/0xc0
remote_function+0x41/0x50
flush_smp_call_function_queue+0x68/0x100
generic_smp_call_function_single_interrupt+0x13/0x30
smp_call_function_single_interrupt+0x3e/0xe0
call_function_single_interrupt+0xf/0x20
</IRQ>
The reason is that while event init code does several checks
for BTS events and prevents several unwanted config bits for
BTS event (like precise_ip), the PERF_EVENT_IOC_PERIOD allows
to create BTS event without those checks being done.
Following sequence will cause the crash:
If we create an 'almost' BTS event with precise_ip and callchains,
and it into a BTS event it will crash the perf_prepare_sample()
function because precise_ip events are expected to come
in with callchain data initialized, but that's not the
case for intel_pmu_drain_bts_buffer() caller.
Adding a check_period callback to be called before the period
is changed via PERF_EVENT_IOC_PERIOD. It will deny the change
if the event would become BTS. Plus adding also the limit_period
check as well.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20190204123532.GA4794@krava
Signed-off-by: Ingo Molnar <mingo@kernel.org>
KVM added a workaround for PEBS events leaking into guests with
commit:
26a4f3c08d ("perf/x86: disable PEBS on a guest entry.")
This uses the VT entry/exit list to add an extra disable of the
PEBS_ENABLE MSR.
Intel also added a fix for this issue to microcode updates on
Haswell/Broadwell/Skylake.
It turns out using the MSR entry/exit list makes VM exits
significantly slower. The list is only needed for disabling
PEBS, because the GLOBAL_CTRL change gets optimized by
KVM into changing the VMCS.
Check for the microcode updates that have the microcode
fix for leaking PEBS, and disable the extra entry/exit list
entry for PEBS_ENABLE. In addition we always clear the
GLOBAL_CTRL for the PEBS counter while running in the guest,
which is enough to make them never fire at the wrong
side of the host/guest transition.
The overhead for VM exits with the filtering active with the patch is
reduced from 8% to 4%.
The microcode patch has already been merged into future platforms.
This patch is one-off thing. The quirks is used here.
For other old platforms which doesn't have microcode patch and quirks,
extra disable of the PEBS_ENABLE MSR is still required.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: bp@alien8.de
Link: https://lkml.kernel.org/r/1549319013-4522-2-git-send-email-kan.liang@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently we check the branch tracing only by checking for the
PERF_COUNT_HW_BRANCH_INSTRUCTIONS event of PERF_TYPE_HARDWARE
type. But we can define the same event with the PERF_TYPE_RAW
type.
Changing the intel_pmu_has_bts() code to check on event's final
hw config value, so both HW types are covered.
Adding unlikely to intel_pmu_has_bts() condition calls, because
it was used in the original code in intel_bts_constraints.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@vger.kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/20181121101612.16272-2-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Implements counter freezing for Arch Perfmon v4 (Skylake and
newer). This allows to speed up the PMI handler by avoiding
unnecessary MSR writes and make it more accurate.
The Arch Perfmon v4 PMI handler is substantially different than
the older PMI handler.
Differences to the old handler:
- It relies on counter freezing, which eliminates several MSR
writes from the PMI handler and lowers the overhead significantly.
It makes the PMI handler more accurate, as all counters get
frozen atomically as soon as any counter overflows. So there is
much less counting of the PMI handler itself.
With the freezing we don't need to disable or enable counters or
PEBS. Only BTS which does not support auto-freezing still needs to
be explicitly managed.
- The PMU acking is done at the end, not the beginning.
This makes it possible to avoid manual enabling/disabling
of the PMU, instead we just rely on the freezing/acking.
- The APIC is acked before reenabling the PMU, which avoids
problems with LBRs occasionally not getting unfreezed on Skylake.
- Looping is only needed to workaround a corner case which several PMIs
are very close to each other. For common cases, the counters are freezed
during PMI handler. It doesn't need to do re-check.
This patch:
- Adds code to enable v4 counter freezing
- Fork <=v3 and >=v4 PMI handlers into separate functions.
- Add kernel parameter to disable counter freezing. It took some time to
debug counter freezing, so in case there are new problems we added an
option to turn it off. Would not expect this to be used until there
are new bugs.
- Only for big core. The patch for small core will be posted later
separately.
Performance:
When profiling a kernel build on Kabylake with different perf options,
measuring the length of all NMI handlers using the nmi handler
trace point:
V3 is without counter freezing.
V4 is with counter freezing.
The value is the average cost of the PMI handler.
(lower is better)
perf options ` V3(ns) V4(ns) delta
-c 100000 1088 894 -18%
-g -c 100000 1862 1646 -12%
--call-graph lbr -c 100000 3649 3367 -8%
--c.g. dwarf -c 100000 2248 1982 -12%
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Link: http://lkml.kernel.org/r/1533712328-2834-2-git-send-email-kan.liang@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The Extended PEBS feature, introduced in the Goldmont Plus
microarchitecture, supports all events as "Extended PEBS".
Introduce flag PMU_FL_PEBS_ALL to indicate the platforms which support
extended PEBS.
To support all events, it needs to support all constraints for PEBS. To
avoid duplicating all the constraints in the PEBS table, making the PEBS
code search the normal constraints too.
Based-on-code-from: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Link: http://lkml.kernel.org/r/20180309021542.11374-1-kan.liang@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Context switches with perf LBR call stack context are fairly expensive
because they do a lot of MSR writes. Currently we unconditionally do the
expensive operation when LBR call stack is enabled. It's not necessary
for some common cases, e.g task -> other kernel thread -> same task.
The LBR registers are not changed, hence they don't need to be
rewritten/restored.
Introduce per-CPU variables to track the last LBR call stack context.
If the same context is scheduled in, the rewrite/restore is not
required, with the following two exceptions:
- The LBR registers may be modified by a normal LBR event, i.e., adding
a new LBR event or scheduling an existing LBR event. In both cases,
the LBR registers are reset first. The last LBR call stack information
is cleared in intel_pmu_lbr_reset(). Restoring the LBR registers is
required.
- The LBR registers are initialized to zero in C6.
If the LBR registers which TOS points is cleared, C6 must be entered
while swapped out. Restoring the LBR registers is required as well.
These exceptions are not common.
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: acme@kernel.org
Cc: eranian@google.com
Link: https://lore.kernel.org/lkml/1528213126-4312-2-git-send-email-kan.liang@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
LBR has a limited stack size. If a task has a deeper call stack than
LBR's stack size, only the overflowed part is reported. A complete call
stack may not be reconstructed by perf tool.
Current code doesn't access all LBR registers. It only read the ones
below the TOS. The LBR registers above the TOS will be discarded
unconditionally.
When a CALL is captured, the TOS is incremented by 1 , modulo max LBR
stack size. The LBR HW only records the call stack information to the
register which the TOS points to. It will not touch other LBR
registers. So the registers above the TOS probably still store the valid
call stack information for an overflowed call stack, which need to be
reported.
To retrieve complete call stack information, we need to start from TOS,
read all LBR registers until an invalid entry is detected.
0s can be used to detect the invalid entry, because:
- When a RET is captured, the HW zeros the LBR register which TOS points
to, then decreases the TOS.
- The LBR registers are reset to 0 when adding a new LBR event or
scheduling an existing LBR event.
- A taken branch at IP 0 is not expected
The context switch code is also modified to save/restore all valid LBR
registers. Furthermore, the LBR registers, which don't have valid call
stack information, need to be reset in restore, because they may be
polluted while swapped out.
Here is a small test program, tchain_deep.
Its call stack is deeper than 32.
noinline void f33(void)
{
int i;
for (i = 0; i < 10000000;) {
if (i%2)
i++;
else
i++;
}
}
noinline void f32(void)
{
f33();
}
noinline void f31(void)
{
f32();
}
... ...
noinline void f1(void)
{
f2();
}
int main()
{
f1();
}
Here is the test result on SKX. The max stack size of SKX is 32.
Without the patch:
$ perf record -e cycles --call-graph lbr -- ./tchain_deep
$ perf report --stdio
#
# Children Self Command Shared Object Symbol
# ........ ........ ........... ................ .................
#
100.00% 99.99% tchain_deep tchain_deep [.] f33
|
--99.99%--f30
f31
f32
f33
With the patch:
$ perf record -e cycles --call-graph lbr -- ./tchain_deep
$ perf report --stdio
# Children Self Command Shared Object Symbol
# ........ ........ ........... ................ ..................
#
99.99% 0.00% tchain_deep tchain_deep [.] f1
|
---f1
f2
f3
f4
f5
f6
f7
f8
f9
f10
f11
f12
f13
f14
f15
f16
f17
f18
f19
f20
f21
f22
f23
f24
f25
f26
f27
f28
f29
f30
f31
f32
f33
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: eranian@google.com
Link: https://lore.kernel.org/lkml/1528213126-4312-1-git-send-email-kan.liang@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
With the cherry-picked perf/urgent commit merged separately we can now
merge all the fixes without conflicts.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The 'freerunning PEBS' and 'large PEBS' are the same thing. Both of these
names appear in the code and in the API, which causes confusion.
Rename 'freerunning PEBS' to 'large PEBS' to unify the code,
which eliminates the confusion.
No functional change.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1520865937-22910-1-git-send-email-kan.liang@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There is no way to get exact auto-reload times and values which are needed
for event updates unless we flush the PEBS buffer.
Introduce intel_pmu_auto_reload_read() to drain the PEBS buffer for
auto reload event. To prevent races with the hardware, we can only
call drain_pebs() when the PMU is disabled.
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Link: http://lkml.kernel.org/r/1518474035-21006-4-git-send-email-kan.liang@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Large fixed period values could be truncated on Broadwell, for example:
perf record -e cycles -c 10000000000
Here the fixed period is 0x2540BE400, but the period which finally applied is
0x540BE400 - which is wrong.
The reason is that x86_pmu::limit_period() uses an u32 parameter, so the
high 32 bits of 'period' get truncated.
This bug was introduced in:
commit 294fe0f52a ("perf/x86/intel: Add INST_RETIRED.ALL workarounds")
It's safe to use u64 instead of u32:
- Although the 'left' is s64, the value of 'left' must be positive when
calling limit_period().
- bdw_limit_period() only modifies the lowest 6 bits, it doesn't touch
the higher 32 bits.
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: 294fe0f52a ("perf/x86/intel: Add INST_RETIRED.ALL workarounds")
Link: http://lkml.kernel.org/r/1519926894-3520-1-git-send-email-kan.liang@linux.intel.com
[ Rewrote unacceptably bad changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Stephane reported that we don't support period for enabling large PEBS
data, which there's no reason for. Adding PERF_SAMPLE_PERIOD into
freerunning flags.
Tested it with:
# perf record -e cycles:P -c 100 --no-timestamp -C 0 --period
Reported-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Kan Liang <kan.liang@intel.com>
Tested-by: Stephane Eranian <eranian@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180201083812.11359-4-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The BTS and PEBS buffers both have their virtual addresses programmed into
the hardware. This means that any access to them is performed via the page
tables. The times that the hardware accesses these are entirely dependent
on how the performance monitoring hardware events are set up. In other
words, there is no way for the kernel to tell when the hardware might
access these buffers.
To avoid perf crashes, place 'debug_store' allocate pages and map them into
the cpu_entry_area.
The PEBS fixup buffer does not need this treatment.
[ tglx: Got rid of the kaiser_add_mapping() complication ]
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: keescook@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The Intel PEBS/BTS debug store is a design trainwreck as it expects virtual
addresses which must be visible in any execution context.
So it is required to make these mappings visible to user space when kernel
page table isolation is active.
Provide enough room for the buffer mappings in the cpu_entry_area so the
buffers are available in the user space visible page tables.
At the point where the kernel side entry area is populated there is no
buffer available yet, but the kernel PMD must be populated. To achieve this
set the entries for these buffers to non present.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[ Note, this is a Git cherry-pick of the following commit:
a47ba4d77e ("perf/x86: Enable free running PEBS for REGS_USER/INTR")
... for easier x86 PTI code testing and back-porting. ]
Currently free running PEBS is disabled when user or interrupt
registers are requested. Most of the registers are actually
available in the PEBS record and can be supported.
So we just need to check for the supported registers and then
allow it: it is all except for the segment register.
For user registers this only works when the counter is limited
to ring 3 only, so this also needs to be checked.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170831214630.21892-1-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
For understanding how the workload maps to memory channels and hardware
behavior, it's very important to collect address maps with physical
addresses. For example, 3D XPoint access can only be found by filtering
the physical address.
Add a new sample type for physical address.
perf already has a facility to collect data virtual address. This patch
introduces a function to convert the virtual address to physical address.
The function is quite generic and can be extended to any architecture as
long as a virtual address is provided.
- For kernel direct mapping addresses, virt_to_phys is used to convert
the virtual addresses to physical address.
- For user virtual addresses, __get_user_pages_fast is used to walk the
pages tables for user physical address.
- This does not work for vmalloc addresses right now. These are not
resolved, but code to do that could be added.
The new sample type requires collecting the virtual address. The
virtual address will not be output unless SAMPLE_ADDR is applied.
For security, the physical address can only be exposed to root or
privileged user.
Tested-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Cc: mpe@ellerman.id.au
Link: http://lkml.kernel.org/r/1503967969-48278-1-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
It can be difficult to figure out for user programs what features
the x86 CPU PMU driver actually supports. Currently it requires
grepping in dmesg, but dmesg is not always available.
This adds a caps directory to /sys/bus/event_source/devices/cpu/,
similar to the caps already used on intel_pt, which can be used to
discover the available capabilities cleanly.
Three capabilities are defined:
- pmu_name: Underlying CPU name known to the driver
- max_precise: Max precise level supported
- branches: Known depth of LBR.
Example:
% grep . /sys/bus/event_source/devices/cpu/caps/*
/sys/bus/event_source/devices/cpu/caps/branches:32
/sys/bus/event_source/devices/cpu/caps/max_precise:3
/sys/bus/event_source/devices/cpu/caps/pmu_name:skylake
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170822185201.9261-3-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Skylake changed the encoding of the PEBS data source field.
Some combinations are not available anymore, but some new cases
e.g. for L4 cache hit are added.
Fix up the conversion table for Skylake, similar as had been done
for Nehalem.
On Skylake server the encoding for L4 actually means persistent
memory. Handle this case too.
To properly describe it in the abstracted perf format I had to add
some new fields. Since a hit can have only one level add a new
field that is an enumeration, not a bit field to describe
the level. It can describe any level. Some numbers are also
used to describe PMEM and LFB.
Also add a new generic remote flag that can be combined with
the generic level to signify a remote cache.
And there is an extension field for the snoop indication to handle
the Forward state.
I didn't add a generic flag for hops because it's not needed
for Skylake.
I changed the existing encodings for older CPUs to also fill in the
new level and remote fields.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: jolsa@kernel.org
Link: http://lkml.kernel.org/r/20170816222156.19953-3-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Minor cleanup: use an explicit x86_pmu flag to handle the
missing Lock / TLB information on Nehalem, instead of always
checking the model number for each PEBS sample.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: jolsa@kernel.org
Link: http://lkml.kernel.org/r/20170816222156.19953-2-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add perf core PMU support for Intel Goldmont Plus CPU cores:
- The init code is based on Goldmont.
- There is a new cache event list, based on the Goldmont cache event
list.
- All four general-purpose performance counters support PEBS.
- The first general-purpose performance counter is for reduced skid
PEBS mechanism. Using :ppp to indicate the event which want to do
reduced skid PEBS.
- Goldmont Plus has 4-wide pipeline for Topdown
Signed-off-by: Kan Liang <kan.liang@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Link: http://lkml.kernel.org/r/20170712134423.17766-1-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently, the SMIs are visible to all performance counters, because
many users want to measure everything including SMIs. But in some
cases, the SMI cycles should not be counted - for example, to calculate
the cost of an SMI itself. So a knob is needed.
When setting FREEZE_WHILE_SMM bit in IA32_DEBUGCTL, all performance
counters will be effected. There is no way to do per-counter freeze
on SMI. So it should not use the per-event interface (e.g. ioctl or
event attribute) to set FREEZE_WHILE_SMM bit.
Adds sysfs entry /sys/device/cpu/freeze_on_smi to set FREEZE_WHILE_SMM
bit in IA32_DEBUGCTL. When set, freezes perfmon and trace messages
while in SMM.
Value has to be 0 or 1. It will be applied to all processors.
Also serialize the entire setting so we don't get multiple concurrent
threads trying to update to different values.
Signed-off-by: Kan Liang <Kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Cc: bp@alien8.de
Cc: jolsa@kernel.org
Link: http://lkml.kernel.org/r/1494600673-244667-1-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Spurious NMIs will be observed with the following command:
while :; do
perf record -bae "cpu/umask=0x01,event=0xcd,ldlat=0x80/pp"
-e "cpu/umask=0x03,event=0x0/"
-e "cpu/umask=0x02,event=0x0/"
-e cycles,branches,cache-misses
-e cache-references -- sleep 10
done
The bug was introduced by commit:
8077eca079 ("perf/x86/pebs: Add workaround for broken OVFL status on HSW+")
That commit clears the status bits for the counters used for PEBS
events, by masking the whole 64 bits pebs_enabled. However, only the
low 32 bits of both status and pebs_enabled are reserved for PEBS-able
counters.
For status bits 32-34 are fixed counter overflow bits. For
pebs_enabled bits 32-34 are for PEBS Load Latency.
In the test case, the PEBS Load Latency event and fixed counter event
could overflow at the same time. The fixed counter overflow bit will
be cleared by mistake. Once it is cleared, the fixed counter overflow
never be processed, which finally trigger spurious NMI.
Correct the PEBS enabled mask by ignoring the non-PEBS bits.
Signed-off-by: Kan Liang <kan.liang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: 8077eca079 ("perf/x86/pebs: Add workaround for broken OVFL status on HSW+")
Link: http://lkml.kernel.org/r/1491333246-3965-1-git-send-email-kan.liang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
