Since the PMU callback runs in irq context, it synchronizes with gt
reset using the reset count. We could run into a case where the PMU
callback could read the reset count before it is updated. This has a
potential of corrupting the busyness stats.
In addition to the reset count, check if the reset bit is set before
capturing busyness.
In addition save the previous stats only if you intend to update them.
v2:
- The 2 reset counts captured in the PMU callback can end up being the
same if they were captured right after the count is incremented in the
reset flow. This can lead to a bad busyness state. Ensure that reset
is not in progress when the initial reset count is captured.
Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211108211057.68783-1-umesh.nerlige.ramappa@intel.com
When i915 receives a context reset notification from GuC, it triggers
an error capture before resetting any outstanding requsts of that
context. Unfortunately, the error capture is not a time bound
operation. In certain situations it can take a long time, particularly
when multiple large LMEM buffers must be read back and eoncoded. If
this delay is longer than other timeouts (heartbeat, test recovery,
etc.) then a full GT reset can be triggered in the middle.
That can result in the context being reset by GuC actually being
destroyed before the error capture completes and the GuC submission
code resumes. Thus, the GuC side can start dereferencing stale
pointers and Bad Things ensue.
So add a refcount get of the context during the entire reset
operation. That way, the context can't be destroyed part way through
no matter what other resets or user interactions occur.
v2:
(Matthew Brost)
- Update patch to work with async error capture
v3:
(Matthew Brost)
- Drop async capture support as that hasn't landed yet
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211108164054.23588-1-matthew.brost@intel.com
With GuC handling scheduling, i915 is not aware of the time that a
context is scheduled in and out of the engine. Since i915 pmu relies on
this info to provide engine busyness to the user, GuC shares this info
with i915 for all engines using shared memory. For each engine, this
info contains:
- total busyness: total time that the context was running (total)
- id: id of the running context (id)
- start timestamp: timestamp when the context started running (start)
At the time (now) of sampling the engine busyness, if the id is valid
(!= ~0), and start is non-zero, then the context is considered to be
active and the engine busyness is calculated using the below equation
engine busyness = total + (now - start)
All times are obtained from the gt clock base. For inactive contexts,
engine busyness is just equal to the total.
The start and total values provided by GuC are 32 bits and wrap around
in a few minutes. Since perf pmu provides busyness as 64 bit
monotonically increasing values, there is a need for this implementation
to account for overflows and extend the time to 64 bits before returning
busyness to the user. In order to do that, a worker runs periodically at
frequency = 1/8th the time it takes for the timestamp to wrap. As an
example, that would be once in 27 seconds for a gt clock frequency of
19.2 MHz.
Note:
There might be an over-accounting of busyness due to the fact that GuC
may be updating the total and start values while kmd is reading them.
(i.e kmd may read the updated total and the stale start). In such a
case, user may see higher busyness value followed by smaller ones which
would eventually catch up to the higher value.
v2: (Tvrtko)
- Include details in commit message
- Move intel engine busyness function into execlist code
- Use union inside engine->stats
- Use natural type for ping delay jiffies
- Drop active_work condition checks
- Use for_each_engine if iterating all engines
- Drop seq locking, use spinlock at GuC level to update engine stats
- Document worker specific details
v3: (Tvrtko/Umesh)
- Demarcate GuC and execlist stat objects with comments
- Document known over-accounting issue in commit
- Provide a consistent view of GuC state
- Add hooks to gt park/unpark for GuC busyness
- Stop/start worker in gt park/unpark path
- Drop inline
- Move spinlock and worker inits to GuC initialization
- Drop helpers that are called only once
v4: (Tvrtko/Matt/Umesh)
- Drop addressed opens from commit message
- Get runtime pm in ping, remove from the park path
- Use cancel_delayed_work_sync in disable_submission path
- Update stats during reset prepare
- Skip ping if reset in progress
- Explicitly name execlists and GuC stats objects
- Since disable_submission is called from many places, move resetting
stats to intel_guc_submission_reset_prepare
v5: (Tvrtko)
- Add a trylock helper that does not sleep and synchronize PMU event
callbacks and worker with gt reset
v6: (CI BAT failures)
- DUTs using execlist submission failed to boot since __gt_unpark is
called during i915 load. This ends up calling the GuC busyness unpark
hook and results in kick-starting an uninitialized worker. Let
park/unpark hooks check if GuC submission has been initialized.
- drop cant_sleep() from trylock helper since rcu_read_lock takes care
of that.
v7: (CI) Fix igt@i915_selftest@live@gt_engines
- For GuC mode of submission the engine busyness is derived from gt time
domain. Use gt time elapsed as reference in the selftest.
- Increase busyness calculation to 10ms duration to ensure batch runs
longer and falls within the busyness tolerances in selftest.
v8:
- Use ktime_get in selftest as before
- intel_reset_trylock_no_wait results in a lockdep splat that is not
trivial to fix since the PMU callback runs in irq context and the
reset paths are tightly knit into the driver. The test that uncovers
this is igt@perf_pmu@faulting-read. Drop intel_reset_trylock_no_wait,
instead use the reset_count to synchronize with gt reset during pmu
callback. For the ping, continue to use intel_reset_trylock since ping
is not run in irq context.
- GuC PM timestamp does not tick when GuC is idle. This can potentially
result in wrong busyness values when a context is active on the
engine, but GuC is idle. Use the RING TIMESTAMP as GPU timestamp to
process the GuC busyness stats. This works since both GuC timestamp and
RING timestamp are synced with the same clock.
- The busyness stats may get updated after the batch starts running.
This delay causes the busyness reported for 100us duration to fall
below 95% in the selftest. The only option at this time is to wait for
GuC busyness to change from idle to active before we sample busyness
over a 100us period.
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Acked-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211027004821.66097-2-umesh.nerlige.ramappa@intel.com
If an error occurs in the front end when multi-lrc requests are getting
generated we need to skip these in the backend but we still need to
emit the breadcrumbs seqno. An issues arises because with multi-lrc
breadcrumbs there is a handshake between the parent and children to make
forward progress. If all the requests are not present this handshake
doesn't work. To work around this, if multi-lrc request has an error we
skip the handshake but still emit the breadcrumbs seqno.
v2:
(John Harrison)
- Add comment explaining the skipping of the handshake logic
- Fix typos in the commit message
v3:
(John Harrison)
- Fix up some comments about the math to NOP the ring
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211014172005.27155-22-matthew.brost@intel.com
Allow multiple batch buffers to be submitted in a single execbuf IOCTL
after a context has been configured with the 'set_parallel' extension.
The number batches is implicit based on the contexts configuration.
This is implemented with a series of loops. First a loop is used to find
all the batches, a loop to pin all the HW contexts, a loop to create all
the requests, a loop to submit (emit BB start, etc...) all the requests,
a loop to tie the requests to the VMAs they touch, and finally a loop to
commit the requests to the backend.
A composite fence is also created for the generated requests to return
to the user and to stick in dma resv slots.
No behavior from the existing IOCTL should be changed aside from when
throttling because the ring for a context is full. In this situation,
i915 will now wait while holding the object locks. This change was done
because the code is much simpler to wait while holding the locks and we
believe there isn't a huge benefit of dropping these locks. If this
proves false we can restructure the code to drop the locks during the
wait.
IGT: https://patchwork.freedesktop.org/patch/447008/?series=93071&rev=1
media UMD: https://github.com/intel/media-driver/pull/1252
v2:
(Matthew Brost)
- Return proper error value if i915_request_create fails
v3:
(John Harrison)
- Add comment explaining create / add order loops + locking
- Update commit message explaining different in IOCTL behavior
- Line wrap some comments
- eb_add_request returns void
- Return -EINVAL rather triggering BUG_ON if cmd parser used
(Checkpatch)
- Check eb->batch_len[*current_batch]
v4:
(CI)
- Set batch len if passed if via execbuf args
- Call __i915_request_skip after __i915_request_commit
(Kernel test robot)
- Initialize rq to NULL in eb_pin_timeline
v5:
(John Harrison)
- Fix typo in comments near bb order loops
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211014172005.27155-21-matthew.brost@intel.com
For some users of multi-lrc, e.g. split frame, it isn't safe to preempt
mid BB. To safely enable preemption at the BB boundary, a handshake
between parent and child is needed, syncing the set of BBs at the
beginning and end of each batch. This is implemented via custom
emit_bb_start & emit_fini_breadcrumb functions and enabled by default if
a context is configured by set parallel extension.
Lastly, this patch updates the process descriptor to the correct size as
the memory used in the handshake is directly after the process
descriptor.
v2:
(John Harrison)
- Fix a few comments wording
- Add struture for parent page layout
v3:
(John Harrison)
- A structure for sync semaphore
- Use offsetof to calc address
- Update commit message
v4:
(John Harrison)
- Fix typos in comment explaining memory map of scratch page
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211014172005.27155-20-matthew.brost@intel.com
Update context and full GPU reset to work with multi-lrc. The idea is
parent context tracks all the active requests inflight for itself and
its children. The parent context owns the reset replaying / canceling
requests as needed.
v2:
(John Harrison)
- Simply loop in find active request
- Add comments to find ative request / reset loop
v3:
(John Harrison)
- s/its'/its/g
- Fix comment when searching for active request
- Reorder if state in __guc_reset_context
v4:
(Kernel test robot)
- Delete unused is_multi_lrc function
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211014172005.27155-15-matthew.brost@intel.com
Implement multi-lrc submission via a single workqueue entry and single
H2G. The workqueue entry contains an updated tail value for each
request, of all the contexts in the multi-lrc submission, and updates
these values simultaneously. As such, the tasklet and bypass path have
been updated to coalesce requests into a single submission.
v2:
(John Harrison)
- s/wqe/wqi
- Use FIELD_PREP macros
- Add GEM_BUG_ONs ensures length fits within field
- Add comment / white space to intel_guc_write_barrier
(Kernel test robot)
- Make need_tasklet a static function
v3:
(Docs)
- A comment for submission_stall_reason
v4:
(Kernel test robot)
- Initialize return value in bypass tasklt submit function
(John Harrison)
- Add comment near work queue defs
- Add BUILD_BUG_ON to ensure WQ_SIZE is a power of 2
- Update write_barrier comment to talk about work queue
v5:
(John Harrison)
- Fix typo in work queue comment
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211014172005.27155-13-matthew.brost@intel.com
Assign contexts in parent-child relationship consecutive guc_ids. This
is accomplished by partitioning guc_id space between ones that need to
be consecutive (1/16 available guc_ids) and ones that do not (15/16 of
available guc_ids). The consecutive search is implemented via the bitmap
API.
This is a precursor to the full GuC multi-lrc implementation but aligns
to how GuC mutli-lrc interface is defined - guc_ids must be consecutive
when using the GuC multi-lrc interface.
v2:
(Daniel Vetter)
- Explicitly state why we assign consecutive guc_ids
v3:
(John Harrison)
- Bring back in spin lock
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211014172005.27155-11-matthew.brost@intel.com
Add multi-lrc context registration H2G. In addition a workqueue and
process descriptor are setup during multi-lrc context registration as
these data structures are needed for multi-lrc submission.
v2:
(John Harrison)
- Move GuC specific fields into sub-struct
- Clean up WQ defines
- Add comment explaining math to derive WQ / PD address
v3:
(John Harrison)
- Add PARENT_SCRATCH_SIZE define
- Update comment explaining multi-lrc register
v4:
(John Harrison)
- Move PARENT_SCRATCH_SIZE to common file
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211014172005.27155-9-matthew.brost@intel.com
Taking a PM reference to prevent intel_gt_wait_for_idle from short
circuiting while any user context has scheduling enabled. Returning GT
idle when it is not can cause all sorts of issues throughout the stack.
v2:
(Daniel Vetter)
- Add might_lock annotations to pin / unpin function
v3:
(CI)
- Drop intel_engine_pm_might_put from unpin path as an async put is
used
v4:
(John Harrison)
- Make intel_engine_pm_might_get/put work with GuC virtual engines
- Update commit message
v5:
- Update commit message again
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211014172005.27155-4-matthew.brost@intel.com
Taking a PM reference to prevent intel_gt_wait_for_idle from short
circuiting while a deregister context H2G is in flight. To do this must
issue the deregister H2G from a worker as context can be destroyed from
an atomic context and taking GT PM ref blows up. Previously we took a
runtime PM from this atomic context which worked but will stop working
once runtime pm autosuspend in enabled.
So this patch is two fold, stop intel_gt_wait_for_idle from short
circuting and fix runtime pm autosuspend.
v2:
(John Harrison)
- Split structure changes out in different patch
(Tvrtko)
- Don't drop lock in deregister_destroyed_contexts
v3:
(John Harrison)
- Flush destroyed contexts before destroying context reg pool
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211014172005.27155-3-matthew.brost@intel.com
Pinned contexts, like the migrate contexts need reset after resume
since their context image may have been lost. Also the GuC needs to
register pinned contexts.
Add a list to struct intel_engine_cs where we add all pinned contexts on
creation, and traverse that list at resume time to reset the pinned
contexts.
This fixes the kms_pipe_crc_basic@suspend-read-crc-pipe-a selftest for now,
but proper LMEM backup / restore is needed for full suspend functionality.
However, note that even with full LMEM backup / restore it may be
desirable to keep the reset since backing up the migrate context images
must happen using memcpy() after the migrate context has become inactive,
and for performance- and other reasons we want to avoid memcpy() from
LMEM.
Also traverse the list at guc_init_lrc_mapping() calling
guc_kernel_context_pin() for the pinned contexts, like is already done
for the kernel context.
v2:
- Don't reset the contexts on each __engine_unpark() but rather at
resume time (Chris Wilson).
v3:
- Reset contexts in the engine sanitize callback. (Chris Wilson)
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Brost Matthew <matthew.brost@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210922062527.865433-6-thomas.hellstrom@linux.intel.com
Rework and simplify the locking with GuC subission. Drop
sched_state_no_lock and move all fields under the guc_state.sched_state
and protect all these fields with guc_state.lock . This requires
changing the locking hierarchy from guc_state.lock -> sched_engine.lock
to sched_engine.lock -> guc_state.lock.
v2:
(Daniele)
- Don't check fields outside of lock during sched disable, check less
fields within lock as some of the outside are no longer needed
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210909164744.31249-18-matthew.brost@intel.com
A subsequent patch will flip the locking hierarchy from
ce->guc_state.lock -> sched_engine->lock to sched_engine->lock ->
ce->guc_state.lock. As such we need to release the submit fence for a
request from an IRQ to break a lock inversion - i.e. the fence must be
release went holding ce->guc_state.lock and the releasing of the can
acquire sched_engine->lock.
v2:
(Daniele)
- Delete request from list before calling irq_work_queue
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210909164744.31249-16-matthew.brost@intel.com
While debugging an issue with full GT resets I went down a rabbit hole
thinking the scrubbing of lost G2H wasn't working correctly. This proved
to be incorrect as this was working just fine but this chase inspired me
to write a selftest to prove that this works. This simple selftest
injects errors dropping various G2H and then issues a full GT reset
proving that the scrubbing of these G2H doesn't blow up.
v2:
(Daniel Vetter)
- Use ifdef instead of macros for selftests
v3:
(Checkpatch)
- A space after 'switch' statement
v4:
(Daniele)
- A comment saying GT won't idle if G2H are lost
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210909164744.31249-12-matthew.brost@intel.com
If the context is reset as a result of the request cancellation the
context reset G2H is received after schedule disable done G2H which is
the wrong order. The schedule disable done G2H release the waiting
request cancellation code which resubmits the context. This races
with the context reset G2H which also wants to resubmit the context but
in this case it really should be a NOP as request cancellation code owns
the resubmit. Use some clever tricks of checking the context state to
seal this race until the GuC firmware is fixed.
v2:
(Checkpatch)
- Fix typos
v3:
(Daniele)
- State that is a bug in the GuC firmware
Fixes: 62eaf0ae21 ("drm/i915/guc: Support request cancellation")
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Cc: <stable@vger.kernel.org>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210909164744.31249-7-matthew.brost@intel.com
A small race that could result in incorrect accounting of the number
of outstanding G2H. Basically prior to this patch we did not increment
the number of outstanding G2H if we encoutered a GT reset while sending
a H2G. This was incorrect as the context state had already been updated
to anticipate a G2H response thus the counter should be incremented.
As part of this change we remove a legacy (now unused) path that was the
last caller requiring a G2H response that was not guaranteed to loop.
This allows us to simplify the accounting as we don't need to handle the
case where the send fails due to the channel being busy.
Also always use helper when decrementing this value.
v2 (Daniele): update GEM_BUG_ON check, pull in dead code removal from
later patch, remove loop param from context_deregister.
Fixes: f4eb1f3fe9 ("drm/i915/guc: Ensure G2H response has space in buffer")
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: <stable@vger.kernel.org>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210909164744.31249-3-matthew.brost@intel.com
Implement a simple static mapping algorithm of the i915 priority levels
(int, -1k to 1k exposed to user) to the 4 GuC levels. Mapping is as
follows:
i915 level < 0 -> GuC low level (3)
i915 level == 0 -> GuC normal level (2)
i915 level < INT_MAX -> GuC high level (1)
i915 level == INT_MAX -> GuC highest level (0)
We believe this mapping should cover the UMD use cases (3 distinct user
levels + 1 kernel level).
In addition to static mapping, a simple counter system is attached to
each context tracking the number of requests inflight on the context at
each level. This is needed as the GuC levels are per context while in
the i915 levels are per request.
v2:
(Daniele)
- Add BUILD_BUG_ON to enforce ordering of priority levels
- Add missing lockdep to guc_prio_fini
- Check for return before setting context registered flag
- Map DISPLAY priority or higher to highest guc prio
- Update comment for guc_prio
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210727002348.97202-33-matthew.brost@intel.com
This adds GuC backend support for i915_request_cancel(), which in turn
makes CONFIG_DRM_I915_REQUEST_TIMEOUT work.
This implementation makes use of fence while there are likely simplier
options. A fence was chosen because of another feature coming soon
which requires a user to block on a context until scheduling is
disabled. In that case we return the fence to the user and the user can
wait on that fence.
v2:
(Daniele)
- A comment about locking the blocked incr / decr
- A comments about the use of the fence
- Update commit message explaining why fence
- Delete redundant check blocked count in unblock function
- Ring buffer implementation
- Comment about blocked in submission path
- Shorter rpm path
v3:
(Checkpatch)
- Fix typos in commit message
(Daniel)
- Rework to simplier locking structure in guc_context_block / unblock
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210727002348.97202-26-matthew.brost@intel.com
