linux/Documentation
Arnaldo Carvalho de Melo c5dfd78eb7 perf core: Allow setting up max frame stack depth via sysctl
The default remains 127, which is good for most cases, and not even hit
most of the time, but then for some cases, as reported by Brendan, 1024+
deep frames are appearing on the radar for things like groovy, ruby.

And in some workloads putting a _lower_ cap on this may make sense. One
that is per event still needs to be put in place tho.

The new file is:

  # cat /proc/sys/kernel/perf_event_max_stack
  127

Chaging it:

  # echo 256 > /proc/sys/kernel/perf_event_max_stack
  # cat /proc/sys/kernel/perf_event_max_stack
  256

But as soon as there is some event using callchains we get:

  # echo 512 > /proc/sys/kernel/perf_event_max_stack
  -bash: echo: write error: Device or resource busy
  #

Because we only allocate the callchain percpu data structures when there
is a user, which allows for changing the max easily, its just a matter
of having no callchain users at that point.

Reported-and-Tested-by: Brendan Gregg <brendan.d.gregg@gmail.com>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
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: Wang Nan <wangnan0@huawei.com>
Cc: Zefan Li <lizefan@huawei.com>
Link: http://lkml.kernel.org/r/20160426002928.GB16708@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-04-27 10:20:39 -03:00
..
ABI i2c: mux: demux-pinctrl: Update docs to new sysfs-attributes 2016-04-07 21:13:02 +02:00
accounting Documentation-getdelays: Apply a recommendation from "checkpatch.pl" in main() 2015-12-24 07:22:32 -07:00
acpi mfd: core: redo ACPI matching of the children devices 2015-10-26 15:25:53 +01:00
aoe
arm ARM: SoC 64-bit changes for v4.6 2016-03-20 15:08:45 -07:00
arm64 arm64: Add workaround for Cavium erratum 27456 2016-02-26 15:14:27 +00:00
auxdisplay
backlight
blackfin
block A relatively boring cycle in the docs tree. There's a few kernel-doc 2016-01-17 11:55:07 -08:00
blockdev cpqarray: remove it from the kernel 2016-03-14 09:06:01 -06:00
bus-devices
cdrom
cgroup-v1 Merge branch 'for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2016-03-18 20:25:49 -07:00
cma
connector
console
cpu-freq Documentation: cpufreq: intel_pstate: fix typo 2016-02-18 20:31:53 +01:00
cpuidle
cris
crypto crypto: doc - Use ahash 2016-02-06 15:33:11 +08:00
development-process
device-mapper dm cache: make the 'mq' policy an alias for 'smq' 2016-03-10 17:12:08 -05:00
devicetree ARM: SoC fixes 2016-04-13 08:57:18 -07:00
dmaengine Merge branch 'topic/async' into for-linus 2016-01-06 15:17:47 +05:30
DocBook Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux 2016-03-21 13:48:00 -07:00
driver-model Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm 2016-03-19 16:31:54 -07:00
dvb [media] media: change email address 2016-01-25 12:01:08 -02:00
early-userspace
EDID
extcon
fault-injection net: Add support for CHANGEUPPER notifier error injection 2015-12-03 11:49:23 -05:00
fb Documentation/fb: add documentation for sm712fb 2015-08-07 15:05:01 -07:00
features arm64 updates for 4.6: 2016-03-17 20:03:47 -07:00
filesystems mm, fs: remove remaining PAGE_CACHE_* and page_cache_{get,release} usage 2016-04-04 10:41:08 -07:00
firmware_class
fmc
fpga usage documentation for FPGA manager core 2015-10-07 18:07:20 +01:00
frv
gpio gpio: documenatation: fix GPIO_LOOKUP{,_IDX} documentation 2016-02-25 16:01:51 +01:00
hid
hwmon hwmon: Create an NSA320 hardware monitoring driver 2016-03-08 18:40:49 -08:00
i2c Doc: i2c: Fix typo in Documentation/i2c 2016-02-10 13:12:14 -07:00
ia64
ide
iio iio: Documentation: Add IIO configfs documentation 2015-12-03 18:19:28 +00:00
infiniband staging/rdma/hfi1: Method to toggle "fast ECN" detection 2016-03-10 20:37:50 -05:00
input Input: add userio module 2015-10-27 18:55:31 -07:00
ioctl gpio: uapi: use 0xB4 as ioctl() major 2016-03-10 16:02:52 +07:00
isdn isdn: i4l: move active-isdn drivers to staging 2016-03-05 15:00:38 -08:00
ja_JP Doc: ja_JP: Fix a typo in HOWTO 2016-02-10 13:14:37 -07:00
kbuild kbuild: document recursive dependency limitation / resolution 2015-10-08 15:36:16 +02:00
kdump
ko_KR Documentation/ko_KR: update maintainer information 2016-02-17 14:10:39 -07:00
laptops
leds Documentation: leds: Add description of brightness setting API 2016-01-04 09:57:31 +01:00
locking Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-11-03 16:10:43 -08:00
m68k
memory-devices
metag
mic Char/Misc patches for 4.6-rc1 2016-03-17 13:47:50 -07:00
mips
misc-devices Merge char-misc-next into staging-next 2016-02-22 14:46:24 -08:00
mmc mmc: core: Remove MMC_CLKGATE 2015-10-26 16:00:09 +01:00
mn10300
mtd Documentation: mtd: improve nand_ecc.txt for readability and correctness 2015-11-17 17:05:14 -08:00
namespaces
netlabel
networking switchdev: fix typo in comments/doc 2016-03-24 14:51:24 -04:00
nfc
nios2
nvdimm libnvdimm: documentation clarifications 2015-11-12 09:55:23 -08:00
nvmem Documentation: nvmem: add nvmem api level and how-to doc 2015-08-05 13:43:45 -07:00
parisc
PCI
pcmcia pcmcia: Fix typo in locking documentation 2015-08-07 14:34:58 +02:00
phy
platform
power PM / runtime: Document steps for device removal 2016-04-05 03:46:59 +02:00
powerpc cxl: Support to flash a new image on the adapter from a guest 2016-03-09 23:39:56 +11:00
pps
prctl Documentation: Fix int/unsigned int comparison 2016-02-17 14:09:43 -07:00
pti
ptp Another relatively boring cycle for the docs tree: typo fixes, translation 2016-03-17 12:09:35 -07:00
rapidio rapidio: add mport char device driver 2016-03-22 15:36:02 -07:00
RCU documentation: Update RCU requirements based on expedited changes 2015-12-05 12:34:32 -08:00
s390 s390/zcore: remove /sys/kernel/debug/zcore/mem 2015-11-27 09:24:12 +01:00
scheduler
scsi st: Fix MTMKPART to work with newer drives 2016-02-23 21:27:02 -05:00
security keys, trusted: seal with a TPM2 authorization policy 2015-12-20 15:27:13 +02:00
serial tty: Remove chars_in_buffer() line discipline method 2016-01-27 15:01:44 -08:00
sh
sound Merge branch 'topic/hda-mst' into for-next 2016-02-10 09:25:15 +01:00
spi spi: tools: move spidev_test metadata 2015-11-30 12:14:12 +00:00
sysctl perf core: Allow setting up max frame stack depth via sysctl 2016-04-27 10:20:39 -03:00
target target/user: Report capability of handling out-of-order completions to userspace 2016-03-10 21:49:09 -08:00
thermal thermal: doc: Add details of devm_thermal_zone_of_sensor_{register,unregister} 2016-03-09 10:51:41 -08:00
timers Another relatively boring cycle for the docs tree: typo fixes, translation 2016-03-17 12:09:35 -07:00
tpm
trace x86, tracing, perf: Add trace point for MSR accesses 2015-12-06 12:56:10 +01:00
usb doc: usb: Fix typo in gadget_multi documentation 2016-04-13 12:02:28 -07:00
vDSO
video4linux [media] saa7134: Add support for Snazio TvPVR PRO 2016-03-03 09:03:48 -03:00
virtual One of the largest releases for KVM... Hardly any generic improvement, 2016-03-16 09:55:35 -07:00
vm mm: thp: set THP defrag by default to madvise and add a stall-free defrag option 2016-03-17 15:09:34 -07:00
w1 w1: masters: omap_hdq: add support for 1-wire mode 2015-10-05 04:47:09 +01:00
watchdog Merge git://www.linux-watchdog.org/linux-watchdog 2016-03-19 19:35:51 -07:00
wimax
x86 x86/mm/pkeys: Add missing Documentation 2016-03-29 11:21:17 +02:00
xtensa
zh_CN Documentation: Chinese translation of arm64/silicon-errata.txt 2016-02-17 14:08:07 -07:00
00-INDEX
adding-syscalls.txt Documentation: describe how to add a system call 2015-08-13 17:54:06 -06:00
applying-patches.txt
assoc_array.txt
atomic_ops.txt locking/atomics, cmpxchg: Privatize the inclusion of asm/cmpxchg.h 2015-09-13 10:35:46 +02:00
bad_memory.txt
basic_profiling.txt
bcache.txt
binfmt_misc.txt
braille-console.txt
bt8xxgpio.txt
btmrvl.txt
BUG-HUNTING
bus-virt-phys-mapping.txt
cachetlb.txt
cgroup-v2.txt Merge branch 'for-4.6-ns' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2016-03-21 10:05:13 -07:00
Changes There is a nice new document from Neil on how pathname lookups work and 2015-11-05 15:59:24 -08:00
circular-buffers.txt
clk.txt clk: change clk_ops' ->determine_rate() prototype 2015-07-27 18:12:01 -07:00
coccinelle.txt
CodeOfConflict
CodingStyle Documentation/CodingStyle: add space before parenthesis in example macro 2016-01-25 12:36:28 -07:00
cpu-hotplug.txt Documentation: cpu-hotplug: Fix sysfs mount instructions 2015-12-10 11:35:30 -07:00
cpu-load.txt
cputopology.txt
crc32.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt
dell_rbu.txt
devices.txt
digsig.txt
DMA-API-HOWTO.txt dma-mapping: always provide the dma_map_ops based implementation 2016-01-20 17:09:18 -08:00
DMA-API.txt DMA-API: fix confusing sentence in Documentation/DMA-API.txt 2016-01-11 18:29:00 -07:00
DMA-attributes.txt ARM: 8506/1: common: DMA-mapping: add DMA_ATTR_ALLOC_SINGLE_PAGES attribute 2016-02-11 15:33:38 +00:00
dma-buf-sharing.txt dma-buf: Update docs for SYNC ioctl 2016-03-21 09:26:45 +01:00
DMA-ISA-LPC.txt
dontdiff Documentation: dontdiff: remove media from dontdiff 2015-11-11 10:08:07 -07:00
dynamic-debug-howto.txt
edac.txt EDAC: Remove references to bluesmoke.sourceforge.net 2015-11-26 14:46:06 +01:00
efi-stub.txt doc: efi-stub.txt: Fix arm64 paths 2015-12-14 15:24:03 +00:00
eisa.txt
email-clients.txt A few more documentation patches that wandered in and have no reason to 2015-11-13 09:19:05 -08:00
flexible-arrays.txt
futex-requeue-pi.txt
gcov.txt
gdb-kernel-debugging.txt
highuid.txt
HOWTO Documentation: Howto: Fixed subtitles style 2016-03-09 15:30:03 -07:00
hsi.txt
hw_random.txt hwrng: doc - Fix device node name reference /dev/hw_random => /dev/hwrng 2015-09-21 22:00:41 +08:00
hwspinlock.txt
init.txt
initrd.txt
intel_txt.txt
Intel-IOMMU.txt iommu/vt-d: Fix link to Intel IOMMU Specification 2016-01-29 12:32:12 +01:00
io_ordering.txt
io-mapping.txt
iostats.txt
IPMI.txt ipmi watchdog : add panic_wdt_timeout parameter 2015-11-16 06:28:43 -06:00
IRQ-affinity.txt
IRQ-domain.txt irqdomain: Documentation updates 2015-10-13 19:01:25 +02:00
IRQ.txt
irqflags-tracing.txt
isapnp.txt
java.txt
kasan.txt mm, kasan: SLAB support 2016-03-25 16:37:42 -07:00
kcov.txt kernel: add kcov code coverage 2016-03-22 15:36:02 -07:00
kernel-doc-nano-HOWTO.txt
kernel-docs.txt Documentation: translations: update linux cross reference link 2016-01-11 18:26:58 -07:00
kernel-parameters.txt USB: uas: Add a new NO_REPORT_LUNS quirk 2016-04-13 12:02:28 -07:00
kernel-per-CPU-kthreads.txt irq_poll: make blk-iopoll available outside the block layer 2015-12-11 11:52:24 -08:00
kmemcheck.txt
kmemleak.txt
kobject.txt
kprobes.txt
kref.txt
kselftest.txt Documentation: kselftest: Remove duplicate word 2016-03-09 15:33:38 -07:00
ldm.txt
local_ops.txt
lockup-watchdogs.txt kernel/watchdog.c: add sysctl knob hardlockup_panic 2015-11-05 19:34:48 -08:00
logo.gif
logo.txt
lzo.txt
magic-number.txt
mailbox.txt Documentation: minor typo fix in mailbox.txt 2015-08-13 18:03:18 -06:00
Makefile spi: Move spi code from Documentation to tools 2015-11-23 14:54:01 +00:00
ManagementStyle
md-cluster.txt md-cluster: update the documentation 2016-01-06 11:39:06 +11:00
md.txt
memory-barriers.txt documentation: Clarify compiler store-fusion example 2016-03-14 15:52:19 -07:00
memory-hotplug.txt memory-hotplug: add automatic onlining policy for the newly added memory 2016-03-15 16:55:16 -07:00
men-chameleon-bus.txt Documentation: Minor changes to men-chameleon-bus.txt 2015-07-24 15:15:17 +02:00
module-signing.txt modsign: Fix documentation on module signing enforcement parameter. 2016-03-12 01:48:11 -07:00
mono.txt
nommu-mmap.txt
ntb.txt
numastat.txt
oops-tracing.txt
padata.txt
parport-lowlevel.txt
parport.txt
percpu-rw-semaphore.txt
phy.txt
pi-futex.txt
pinctrl.txt
pnp.txt
preempt-locking.txt
printk-formats.txt mm, printk: introduce new format string for flags 2016-03-15 16:55:16 -07:00
pwm.txt
ramoops.txt
rbtree.txt documentation: fix small typo in rbtree.txt 2015-09-13 14:38:50 -06:00
remoteproc.txt
rfkill.txt rfkill: Add documentation about LED triggers 2016-02-24 09:13:12 +01:00
robust-futex-ABI.txt
robust-futexes.txt
rpmsg.txt
rtc.txt rtc: implement a sysfs interface for clock offset 2016-03-14 17:08:16 +01:00
SAK.txt
SecurityBugs
serial-console.txt
sgi-ioc4.txt
SM501.txt
smsc_ece1099.txt
sparse.txt
stable_api_nonsense.txt
stable_kernel_rules.txt stable_kernel_rules.txt: Remove extra space after Cc: 2015-11-20 16:54:57 -07:00
static-keys.txt locking/static_keys: Fix up the static keys documentation 2015-09-15 07:12:06 +02:00
SubmitChecklist
SubmittingDrivers
SubmittingPatches SubmittingPatches: fix spelling of "git send-email" 2016-01-25 12:30:18 -07:00
svga.txt
sysfs-rules.txt
sysrq.txt mm, oom: do not panic for oom kills triggered from sysrq 2015-09-08 15:35:28 -07:00
this_cpu_ops.txt
ubsan.txt UBSAN: run-time undefined behavior sanity checker 2016-01-20 17:09:18 -08:00
unaligned-memory-access.txt
unicode.txt
unshare.txt
vfio.txt
VGA-softcursor.txt
vgaarbiter.txt
video-output.txt
vme_api.txt
volatile-considered-harmful.txt
workqueue.txt
xillybus.txt
xz.txt
zorro.txt