No description
  • C 96.9%
  • Assembly 0.9%
  • Rust 0.6%
  • Shell 0.6%
  • Python 0.5%
  • Other 0.3%
Find a file
Arnaldo Carvalho de Melo a7672d1df5 perf evlist: Change the COMM when preparing the workload
It was reported that --exclude-perf wasn't working, as tracepoints were
appearing in 'perf script' output as having the 'perf' COMM, that is
just the window in evlist__prepare_workload() after the fork() and
before the execvp() call for workloads specified in the command line.

Example:

  # perf record -e kmem:kmalloc --filter 'bytes_alloc<650 && bytes_alloc>620' --exclude-perf -e kmem:kfree --exclude-perf -aR sleep 30

Then:

  # perf script
          perf 15905 [009] 1498.356094: kmem:kfree: call_site=perf_event_mmap+0x279 ptr=(nil)
          perf 15905 [009] 1498.356116: kmem:kfree: call_site=free_bprm+0x8f ptr=(nil)
          perf 15905 [009] 1498.356116: kmem:kfree: call_site=do_execveat_common+0x19d ptr=0xffff9cf750421c00
          perf 15905 [009] 1498.356138: kmem:kfree: call_site=perf_event_mmap+0x279 ptr=(nil)
          perf 15905 [009] 1498.356148: kmem:kfree: call_site=free_bprm+0x8f ptr=(nil)
          perf 15905 [009] 1498.356148: kmem:kfree: call_site=do_execveat_common+0x19d ptr=0xffff9cf750421c00
          perf 15905 [009] 1498.356168: kmem:kfree: call_site=perf_event_mmap+0x279 ptr=(nil)
          perf 15905 [009] 1498.356176: kmem:kfree: call_site=free_bprm+0x8f ptr=(nil)
  <SNIP>
          perf 15905 [009] 1498.356348: kmem:kfree: call_site=perf_event_mmap+0x279 ptr=(nil)
          perf 15905 [014] 1498.356386: kmem:kfree: call_site=security_compute_sid.part.0+0x3b2 ptr=(nil)
          perf 15905 [014] 1498.356423: kmem:kfree: call_site=load_elf_binary+0x207 ptr=0xffff9cf5b2a34220
          perf 15905 [014] 1498.356694: kmem:kfree: call_site=__free_slab+0xb5 ptr=0xffff9cf6d0b3b000
         sleep 15905 [014] 1498.356739: kmem:kfree: call_site=perf_event_mmap+0x279 ptr=(nil)

Use prctl() to show that that is just the preparation of the workload:

  # perf script
     perf-exec 19036 [009] 2199.357582: kmem:kfree: call_site=perf_event_mmap+0x279 ptr=(nil)
     perf-exec 19036 [009] 2199.357604: kmem:kfree: call_site=free_bprm+0x8f ptr=(nil)
     perf-exec 19036 [009] 2199.357604: kmem:kfree: call_site=do_execveat_common+0x19d ptr=0xffff9cf786459800
     perf-exec 19036 [009] 2199.357630: kmem:kfree: call_site=perf_event_mmap+0x279 ptr=(nil)
  <SNIP>
     perf-exec 19036 [000] 2199.358277: kmem:kfree: call_site=__free_slab+0xb5 ptr=0xffff9cf786fb9c00
     perf-exec 19036 [000] 2199.358278: kmem:kfree: call_site=__free_slab+0xb5 ptr=0xffff9cf786458200
     perf-exec 19036 [000] 2199.358279: kmem:kfree: call_site=__free_slab+0xb5 ptr=0xffff9cf786458600
         sleep 19036 [000] 2199.358316: kmem:kfree: call_site=perf_event_mmap+0x279 ptr=(nil)
         sleep 19036 [000] 2199.358323: kmem:kfree: call_site=perf_event_mmap+0x279 ptr=(nil)
         sleep 19036 [000] 2199.358330: kmem:kfree: call_site=perf_event_mmap+0x279 ptr=0xffff9cf58be2d000
         sleep 19036 [000] 2199.358337: kmem:kfree: call_site=perf_event_mmap+0x279 ptr=0xffff9cf58be2d000
         sleep 19036 [000] 2199.358339: kmem:kfree: call_site=perf_event_mmap+0x279 ptr=0xffff9cf58be2d000
         sleep 19036 [000] 2199.358341: kmem:kfree: call_site=perf_event_mmap+0x279 ptr=0xffff9cf58be2d000

Reporter: zhanweiw <wingfancy@hotmail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=212213
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
History 2021-03-15 10:13:22 -03:00
arch
block
certs
crypto
Documentation
drivers
fs
include
init
ipc
kernel
lib
LICENSES
mm
net
samples
scripts
security
sound
tools
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile
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.