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| author | Arnaldo Carvalho de Melo <acme@redhat.com> | 2021-03-15 16:13:22 +0300 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2021-03-15 16:13:22 +0300 |
| commit | a7672d1df5737009bd5339b80da429da7ceb9964 (patch) | |
| tree | 93d24f455949bbb9d5a34ec6a571ad810399fbb1 /tools/perf/util/evlist.c | |
| parent | 83ff0f93b0803700b018f6cce06f50439dc1348c (diff) | |
| download | linux-a7672d1df5737009bd5339b80da429da7ceb9964.tar.xz | |
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>
Diffstat (limited to 'tools/perf/util/evlist.c')
| -rw-r--r-- | tools/perf/util/evlist.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index 882cd1f721d9..435bbfd00551 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -36,6 +36,7 @@ #include <fcntl.h> #include <sys/ioctl.h> #include <sys/mman.h> +#include <sys/prctl.h> #include <linux/bitops.h> #include <linux/hash.h> @@ -1406,6 +1407,13 @@ int evlist__prepare_workload(struct evlist *evlist, struct target *target, const fcntl(go_pipe[0], F_SETFD, FD_CLOEXEC); /* + * Change the name of this process not to confuse --exclude-perf users + * that sees 'perf' in the window up to the execvp() and thinks that + * perf samples are not being excluded. + */ + prctl(PR_SET_NAME, "perf-exec"); + + /* * Tell the parent we're ready to go */ close(child_ready_pipe[1]); |