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Yang Jihong bcc8b3e88d perf kwork: Implement perf kwork timehist
Implements framework of perf kwork timehist,
to provide an analysis of kernel work events.

Test cases:

  # perf kwork tim
   Runtime start      Runtime end        Cpu     Kwork name                      Runtime     Delaytime
                                                 (TYPE)NAME:NUM                  (msec)      (msec)
   -----------------  -----------------  ------  ------------------------------  ----------  ----------
        91576.060290       91576.060344  [0000]  (s)RCU:9                             0.055       0.111
        91576.061470       91576.061547  [0000]  (s)SCHED:7                           0.077       0.073
        91576.062604       91576.062697  [0001]  (s)RCU:9                             0.094       0.409
        91576.064443       91576.064517  [0002]  (s)RCU:9                             0.074       0.114
        91576.065144       91576.065211  [0000]  (s)SCHED:7                           0.067       0.058
        91576.066564       91576.066609  [0003]  (s)RCU:9                             0.045       0.110
        91576.068495       91576.068559  [0000]  (s)SCHED:7                           0.064       0.059
        91576.068900       91576.068996  [0004]  (s)RCU:9                             0.096       0.726
        91576.069364       91576.069420  [0002]  (s)RCU:9                             0.056       0.082
        91576.069649       91576.069701  [0004]  (s)RCU:9                             0.052       0.111
        91576.070147       91576.070206  [0000]  (s)SCHED:7                           0.060       0.057
        91576.073147       91576.073202  [0000]  (s)SCHED:7                           0.054       0.060
  <SNIP>

  # perf kwork tim --max-stack 2 -g
   Runtime start      Runtime end        Cpu     Kwork name                      Runtime     Delaytime
                                                 (TYPE)NAME:NUM                  (msec)      (msec)
   -----------------  -----------------  ------  ------------------------------  ----------  ----------
        91576.060290       91576.060344  [0000]  (s)RCU:9                             0.055       0.111   irq_exit_rcu <- sysvec_apic_timer_interrupt
        91576.061470       91576.061547  [0000]  (s)SCHED:7                           0.077       0.073   irq_exit_rcu <- sysvec_call_function_single
        91576.062604       91576.062697  [0001]  (s)RCU:9                             0.094       0.409   irq_exit_rcu <- sysvec_apic_timer_interrupt
        91576.064443       91576.064517  [0002]  (s)RCU:9                             0.074       0.114   irq_exit_rcu <- sysvec_apic_timer_interrupt
        91576.065144       91576.065211  [0000]  (s)SCHED:7                           0.067       0.058   irq_exit_rcu <- sysvec_call_function_single
        91576.066564       91576.066609  [0003]  (s)RCU:9                             0.045       0.110   irq_exit_rcu <- sysvec_apic_timer_interrupt
        91576.068495       91576.068559  [0000]  (s)SCHED:7                           0.064       0.059   irq_exit_rcu <- sysvec_call_function_single
        91576.068900       91576.068996  [0004]  (s)RCU:9                             0.096       0.726   irq_exit_rcu <- sysvec_apic_timer_interrupt
        91576.069364       91576.069420  [0002]  (s)RCU:9                             0.056       0.082   irq_exit_rcu <- sysvec_apic_timer_interrupt
        91576.069649       91576.069701  [0004]  (s)RCU:9                             0.052       0.111   irq_exit_rcu <- sysvec_apic_timer_interrupt
  <SNIP>

Committer testing:

  # perf kwork -k workqueue timehist | head -40
   Runtime start      Runtime end        Cpu     Kwork name                      Runtime     Delaytime
                                                 (TYPE)NAME:NUM                  (msec)      (msec)
   -----------------  -----------------  ------  ------------------------------  ----------  ----------
        26520.211825       26520.211832  [0019]  (w)free_work                         0.007       0.004
        26520.212929       26520.212934  [0020]  (w)free_work                         0.005       0.004
        26520.213226       26520.213228  [0014]  (w)kfree_rcu_work                    0.002       0.004
        26520.214057       26520.214061  [0021]  (w)free_work                         0.004       0.004
        26520.221239       26520.221241  [0007]  (w)kfree_rcu_work                    0.002       0.009
        26520.223232       26520.223238  [0013]  (w)psi_avgs_work                     0.005       0.006
        26520.230057       26520.230060  [0020]  (w)free_work                         0.003       0.003
        26520.270428       26520.270434  [0015]  (w)free_work                         0.006       0.004
        26520.270546       26520.270550  [0014]  (w)free_work                         0.004       0.003
        26520.281626       26520.281629  [0015]  (w)free_work                         0.003       0.002
        26520.287225       26520.287230  [0012]  (w)psi_avgs_work                     0.005       0.008
        26520.287231       26520.287235  [0001]  (w)psi_avgs_work                     0.004       0.011
        26520.287236       26520.287239  [0001]  (w)psi_avgs_work                     0.003       0.012
        26520.329488       26520.329492  [0024]  (w)free_work                         0.004       0.004
        26520.330600       26520.330605  [0007]  (w)free_work                         0.005       0.004
        26520.334218       26520.334218  [0007]  (w)kfree_rcu_monitor                 0.001       0.002
        26520.335220       26520.335221  [0005]  (w)kfree_rcu_monitor                 0.001       0.004
        26520.343980       26520.343985  [0007]  (w)free_work                         0.005       0.002
        26520.345093       26520.345097  [0006]  (w)free_work                         0.004       0.003
        26520.351233       26520.351238  [0027]  (w)psi_avgs_work                     0.005       0.008
        26520.353228       26520.353229  [0007]  (w)kfree_rcu_work                    0.001       0.002
        26520.353229       26520.353231  [0005]  (w)kfree_rcu_work                    0.001       0.006
        26520.382381       26520.382383  [0006]  (w)free_work                         0.003       0.002
        26520.386547       26520.386548  [0006]  (w)free_work                         0.002       0.001
        26520.391243       26520.391245  [0015]  (w)console_callback                  0.002       0.016
        26520.415369       26520.415621  [0027]  (w)btrfs_work_helper                 0.252
        26520.415351       26520.416174  [0002]  (w)btrfs_work_helper                 0.823       0.037
        26520.415343       26520.416304  [0031]  (w)btrfs_work_helper                 0.961
        26520.415335       26520.417078  [0001]  (w)btrfs_work_helper                 1.743
        26520.415250       26520.417564  [0002]  (w)wb_workfn                         2.314
        26520.424777       26520.424787  [0002]  (w)btrfs_work_helper                 0.010
        26520.424788       26520.424798  [0002]  (w)btrfs_work_helper                 0.010
        26520.424790       26520.424805  [0001]  (w)btrfs_work_helper                 0.016       0.016
        26520.424801       26520.424807  [0002]  (w)btrfs_work_helper                 0.006
        26520.424809       26520.424831  [0002]  (w)btrfs_work_helper                 0.022       0.030
        26520.424824       26520.424835  [0027]  (w)btrfs_work_helper                 0.011
        26520.424809       26520.424867  [0001]  (w)btrfs_work_helper                 0.059       0.032
  #

Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220709015033.38326-14-yangjihong1@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-07-26 16:31:54 -03:00
arch - Improve the check whether the kernel supports WP mappings so that it 2022-07-17 08:27:30 -07:00
block block: fix missing blkcg_bio_issue_init 2022-07-14 10:54:49 -06:00
certs Certs changes 2022-06-21 12:13:53 -05:00
crypto crypto: s390 - do not depend on CRYPTO_HW for SIMD implementations 2022-07-06 20:04:06 -07:00
Documentation RISC-V: 2022-07-15 10:31:46 -07:00
drivers Second v5.19 rc pull request 2022-07-18 17:16:22 -07:00
fs for-5.19-rc7-tag 2022-07-16 13:48:55 -07:00
include Input updates for v5.19-rc6 2022-07-17 07:52:46 -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 watchqueue: make sure to serialize 'wqueue->defunct' properly 2022-07-20 10:46:07 -07:00
lib ubsan: disable UBSAN_DIV_ZERO for clang 2022-07-14 15:45:26 -07:00
LICENSES
mm mm: split huge PUD on wp_huge_pud fallback 2022-07-03 15:42:33 -07:00
net net/tls: Check for errors in tls_device_init 2022-07-14 10:12:39 -07:00
samples Fixes and minor clean ups for tracing: 2022-07-12 16:17:40 -07:00
scripts Just when you thought that all the speculation bugs were addressed and 2022-07-11 18:15:25 -07:00
security lockdown: Fix kexec lockdown bypass with ima policy 2022-07-20 09:56:48 -07:00
sound ALSA: hda/realtek - Enable the headset-mic on a Xiaomi's laptop 2022-07-13 12:42:41 +02:00
tools perf kwork: Implement perf kwork timehist 2022-07-26 16:31:54 -03:00
usr
virt KVM: x86: disable preemption around the call to kvm_arch_vcpu_{un|}blocking 2022-06-09 10:52:20 -04:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap cxl fixes for 5.19-rc6 2022-07-08 12:55:25 -07:00
COPYING
CREDITS MAINTAINERS: mark ARM/PALM TREO SUPPORT orphan 2022-07-07 15:17:00 +02:00
Kbuild
Kconfig
MAINTAINERS spi: Fixes for v5.19 2022-07-15 10:23:43 -07:00
Makefile Linux 5.19-rc7 2022-07-17 13:30:22 -07:00
README

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.