[PATCH 0/1] perf/urgent fix

[PATCH 0/1] perf/urgent fix

[Arnaldo Carvalho de Melo]

Hi Ingo,

	Please consider pulling,

- Arnaldo

The following changes since commit ebfb4988f0378e2ac3b4a0aa1ea20d724293f392:

  perf/x86/intel: Fix constraint access (2015-09-13 09:37:10 +0200)

are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git tags/perf-urgent-for-mingo

for you to fetch changes up to caa470475d9b59eeff093ae650800d34612c4379:

  perf header: Fixup reading of HEADER_NRCPUS feature (2015-09-13 11:41:34 -0300)

----------------------------------------------------------------
perf/urgent fix:

User visible:

- The values of _SC_NPROCESSORS_CONF and _SC_NPROCESSORS_ONLN (sysconf(3)) were
  being read from perf.data files in the inverse order they are written, fix it.
  (Arnaldo Carvalho de Melo)

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

----------------------------------------------------------------
Arnaldo Carvalho de Melo (1):
      perf header: Fixup reading of HEADER_NRCPUS feature

 tools/perf/util/header.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

[PATCH 1/1] perf header: Fixup reading of HEADER_NRCPUS feature

[Arnaldo Carvalho de Melo]

From: Arnaldo Carvalho de Melo <acme@redhat.com>

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>
---
 tools/perf/util/header.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 41814547da15..fce6634aebe2 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1438,7 +1438,7 @@ 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))
@@ -1447,7 +1447,7 @@ 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;
 }
 
-- 
2.1.0

Re: [PATCH 0/1] perf/urgent fix

[Ingo Molnar]

* Arnaldo Carvalho de Melo <acme@kernel.org> wrote:

> Hi Ingo,
> 
> 	Please consider pulling,
> 
> - Arnaldo
> 
> The following changes since commit ebfb4988f0378e2ac3b4a0aa1ea20d724293f392:
> 
>   perf/x86/intel: Fix constraint access (2015-09-13 09:37:10 +0200)
> 
> are available in the git repository at:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git tags/perf-urgent-for-mingo
> 
> for you to fetch changes up to caa470475d9b59eeff093ae650800d34612c4379:
> 
>   perf header: Fixup reading of HEADER_NRCPUS feature (2015-09-13 11:41:34 -0300)
> 
> ----------------------------------------------------------------
> perf/urgent fix:
> 
> User visible:
> 
> - The values of _SC_NPROCESSORS_CONF and _SC_NPROCESSORS_ONLN (sysconf(3)) were
>   being read from perf.data files in the inverse order they are written, fix it.
>   (Arnaldo Carvalho de Melo)
> 
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> 
> ----------------------------------------------------------------
> Arnaldo Carvalho de Melo (1):
>       perf header: Fixup reading of HEADER_NRCPUS feature
> 
>  tools/perf/util/header.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Pulled, thanks Arnaldo!

	Ingo