Skip to content

L
linux
Switch branch/tag
  1. 21 Feb, 2012 1 commit
    • Stephane Eranian's avatar
      perf tools: fix broken perf record -a mode · 6b1bee90
      Stephane Eranian authored 
      The following commit:
b52956c9 perf tools: Allow multiple threads or processes in record, stat, top

introduced a bug in the thread_map code which caused perf record -a to
not setup system-wide monitoring properly.

$ taskset -c 1 noploop 1000 &
$ perf record -a -C 1 sleep 10
$ perf report -D | tail -20
cycles stats:
           TOTAL events:       4413
            MMAP events:       4025
            COMM events:        340
          SAMPLE events:         48

Here I was expecting about 10,000 samples and not 48.

In system-wide mode, the PID passed to perf_event_open() must be -1 and
it was 0. That caused the kernel to setup a per-process event on PID:0.
Consequently, the number of samples captured does not correspond to the
requested measurement.

The following one-liner fixes the problem for me with or without -C.

I would also suggest to change the malloc() to something that matches
the struct definition. thread_map->map[] is declared as int map[] and
not pid_t map[]. If map[] can only contain pids, then change the struct
definition.
Acked-by: default avatarDavid Ahern <dsahern@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120221145424.GA6757@quadSigned-off-by: default avatarStephane Eranian <eranian@google.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      6b1bee90
  3. 17 Feb, 2012 4 commits
  5. 14 Feb, 2012 15 commits
  7. 13 Feb, 2012 8 commits
  9. 11 Feb, 2012 4 commits
  11. 09 Feb, 2012 2 commits
    • David Ahern's avatar
      perf record: No build id option fails · d3665498
      David Ahern authored 
      A recent refactoring of perf-record introduced the following:

perf record -a -B
Couldn't generating buildids. Use --no-buildid to profile anyway.
sleep: Terminated

I believe the triple negative was meant to be only a double negative.
:-) While I'm there, fixed the grammar on the error message.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1328567272-13190-1-git-send-email-dsahern@gmail.comSigned-off-by: default avatarDavid Ahern <dsahern@gmail.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      d3665498
    • Stephane Eranian's avatar
      perf tools: fix endianness detection in perf.data · 73323f54
      Stephane Eranian authored 
      The current version of perf detects whether or not the perf.data file is
written in a different endianness using the attr_size field in the
header of the file. This field represents sizeof(struct perf_event_attr)
as known to perf record. If the sizes do not match, then perf tries the
byte-swapped version. If they match, then the tool assumes a different
endianness.

The issue with the approach is that it assumes the size of
perf_event_attr always has to match between perf record and perf report.
However, the kernel perf_event ABI is extensible.  New fields can be
added to struct perf_event_attr. Consequently, it is not possible to use
attr_size to detect endianness.

This patch takes another approach by using the magic number written at
the beginning of the perf.data file to detect endianness. The magic
number is an eight-byte signature.  It's primary purpose is to identify
(signature) a perf.data file. But it could also be used to encode the
endianness.

The patch introduces a new value for this signature. The key difference
is that the signature is written differently in the file depending on
the endianness. Thus, by comparing the signature from the file with the
tool's own signature it is possible to detect endianness. The new
signature is "PERFILE2".

Backward compatiblity with existing perf.data file is ensured.
Tested-by: default avatarDavid Ahern <dsahern@gmail.com>
Acked-by: default avatarDavid Ahern <dsahern@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Arun Sharma <asharma@fb.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Lin Ming <ming.m.lin@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roberto Agostino Vitillo <ravitillo@lbl.gov>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Vince Weaver <vweaver1@eecs.utk.edu>
Link: http://lkml.kernel.org/r/1328187288-24395-15-git-send-email-eranian@google.comSigned-off-by: default avatarStephane Eranian <eranian@google.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      73323f54
  13. 07 Feb, 2012 3 commits
  15. 06 Feb, 2012 3 commits
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7