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Namhyung Kim 407b36f69e perf lock: Use BPF for lock contention analysis
Add -b/--use-bpf option to use BPF to collect lock contention stats.
For simplicity it now runs system-wide and requires C-c to stop.
Upcoming changes will add the usual filtering.

  $ sudo perf lock con -b
  ^C
   contended   total wait     max wait     avg wait         type   caller

          42    192.67 us     13.64 us      4.59 us     spinlock   queue_work_on+0x20
          23     85.54 us     10.28 us      3.72 us     spinlock   worker_thread+0x14a
           6     13.92 us      6.51 us      2.32 us        mutex   kernfs_iop_permission+0x30
           3     11.59 us     10.04 us      3.86 us        mutex   kernfs_dop_revalidate+0x3c
           1      7.52 us      7.52 us      7.52 us     spinlock   kthread+0x115
           1      7.24 us      7.24 us      7.24 us     rwlock:W   sys_epoll_wait+0x148
           2      7.08 us      3.99 us      3.54 us     spinlock   delayed_work_timer_fn+0x1b
           1      6.41 us      6.41 us      6.41 us     spinlock   idle_balance+0xa06
           2      2.50 us      1.83 us      1.25 us        mutex   kernfs_iop_lookup+0x2f
           1      1.71 us      1.71 us      1.71 us        mutex   kernfs_iop_getattr+0x2c

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Blake Jones <blakejones@google.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20220729200756.666106-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-08-01 09:28:38 -03:00
arch - Update the mitigations= kernel param documentation 2022-07-31 09:26:53 -07:00
block block: fix missing blkcg_bio_issue_init 2022-07-14 10:54:49 -06:00
certs certs: make system keyring depend on x509 parser 2022-07-24 12:53:55 -07:00
crypto crypto: s390 - do not depend on CRYPTO_HW for SIMD implementations 2022-07-06 20:04:06 -07:00
Documentation - Update the mitigations= kernel param documentation 2022-07-31 09:26:53 -07:00
drivers Fix a NULL pointer deref in the Allwinner clk driver with a one liner. 2022-07-31 09:52:20 -07:00
fs Thirteen hotfixes, Eight are cc:stable and the remainder are for post-5.18 2022-07-26 19:38:46 -07:00
include LoongArch fixes for v5.19-final 2022-07-29 10:10:30 -07:00
init gcc-12: disable '-Warray-bounds' universally for now 2022-06-09 10:11:12 -07:00
ipc ipc: Free mq_sysctls if ipc namespace creation failed 2022-06-22 17:47:41 -05:00
kernel - Update the mitigations= kernel param documentation 2022-07-31 09:26:53 -07:00
lib ubsan: disable UBSAN_DIV_ZERO for clang 2022-07-14 15:45:26 -07:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm Two hotfixes, both cc:stable. 2022-07-29 21:02:35 -07:00
net net: ping6: Fix memleak in ipv6_renew_options(). 2022-07-28 10:42:08 -07:00
samples Fixes and minor clean ups for tracing: 2022-07-12 16:17:40 -07:00
scripts scripts/gdb: Fix gdb 'lx-symbols' command 2022-07-21 10:40:55 -07:00
security lockdown: Fix kexec lockdown bypass with ima policy 2022-07-20 09:56:48 -07:00
sound ASoC: Drop Rockchip BCLK management for v5.19 2022-07-15 12:31:07 +02:00
tools perf lock: Use BPF for lock contention analysis 2022-08-01 09:28:38 -03:00
usr Not a lot of material this cycle. Many singleton patches against various 2022-05-27 11:22:03 -07:00
virt KVM: x86: disable preemption around the call to kvm_arch_vcpu_{un|}blocking 2022-06-09 10:52:20 -04:00
.clang-format clang-format: Fix space after for_each macros 2022-05-20 19:27:16 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore kbuild: split the second line of *.mod into *.usyms 2022-05-08 03:16:59 +09:00
.mailmap ARM: SoC fixes for 5.19, part 4 2022-07-27 09:43:07 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: mark ARM/PALM TREO SUPPORT orphan 2022-07-07 15:17:00 +02:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Pin control fixes for the v5.19 kernel cycle: 2022-07-22 12:24:04 -07:00
Makefile Linux 5.19 2022-07-31 14:03:01 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.