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| author | Arnaldo Carvalho de Melo <acme@redhat.com> | 2015-09-11 12:36:12 -0300 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2015-10-27 22:12:57 -0400 |
| commit | 835199c03a9afc36cab02e76f59e7c67b8ae324d (patch) | |
| tree | fb51701a676cbff292ca913c0e8a61b099084d7e /tools | |
| parent | 6299a825f2b7ac2753af8c017d4b9a185d412780 (diff) | |
| download | lwn-835199c03a9afc36cab02e76f59e7c67b8ae324d.tar.gz lwn-835199c03a9afc36cab02e76f59e7c67b8ae324d.zip | |
perf header: Fixup reading of HEADER_NRCPUS feature
[ Upstream commit caa470475d9b59eeff093ae650800d34612c4379 ]
The original patch introducing this header wrote the number of CPUs available
and online in one order and then swapped those values when reading, fix it.
Before:
# perf record usleep 1
# perf report --header-only | grep 'nrcpus \(online\|avail\)'
# nrcpus online : 4
# nrcpus avail : 4
# echo 0 > /sys/devices/system/cpu/cpu2/online
# perf record usleep 1
# perf report --header-only | grep 'nrcpus \(online\|avail\)'
# nrcpus online : 4
# nrcpus avail : 3
# echo 0 > /sys/devices/system/cpu/cpu1/online
# perf record usleep 1
# perf report --header-only | grep 'nrcpus \(online\|avail\)'
# nrcpus online : 4
# nrcpus avail : 2
After the fix, bringing back the CPUs online:
# perf report --header-only | grep 'nrcpus \(online\|avail\)'
# nrcpus online : 2
# nrcpus avail : 4
# echo 1 > /sys/devices/system/cpu/cpu2/online
# perf record usleep 1
# perf report --header-only | grep 'nrcpus \(online\|avail\)'
# nrcpus online : 3
# nrcpus avail : 4
# echo 1 > /sys/devices/system/cpu/cpu1/online
# perf record usleep 1
# perf report --header-only | grep 'nrcpus \(online\|avail\)'
# nrcpus online : 4
# nrcpus avail : 4
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: fbe96f29ce4b ("perf tools: Make perf.data more self-descriptive (v8)")
Link: http://lkml.kernel.org/r/20150911153323.GP23511@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/perf/util/header.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 26f5b2fe5dc8..74caa262ace5 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -1775,7 +1775,7 @@ static int process_nrcpus(struct perf_file_section *section __maybe_unused, if (ph->needs_swap) nr = bswap_32(nr); - ph->env.nr_cpus_online = nr; + ph->env.nr_cpus_avail = nr; ret = readn(fd, &nr, sizeof(nr)); if (ret != sizeof(nr)) @@ -1784,7 +1784,7 @@ static int process_nrcpus(struct perf_file_section *section __maybe_unused, if (ph->needs_swap) nr = bswap_32(nr); - ph->env.nr_cpus_avail = nr; + ph->env.nr_cpus_online = nr; return 0; } |