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  1. 09 Mar, 2012 4 commits
    • Stephane Eranian's avatar
      perf: Add ABI reference sizes · cb5d7699
      Stephane Eranian authored 
      This patch adds reference sizes for revision 1
and 2 of the perf_event ABI, i.e., the size of
the perf_event_attr struct.

With Rev1: config2 was added = +8 bytes
With Rev2: branch_sample_type was added = +8 bytes

Adds the definition for Rev1, Rev2.

This is useful for tools trying to decode the revision
numbers based on the size of the struct.
Signed-off-by: default avatarStephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: robert.richter@amd.com
Cc: ming.m.lin@intel.com
Cc: andi@firstfloor.org
Cc: asharma@fb.com
Cc: ravitillo@lbl.gov
Cc: vweaver1@eecs.utk.edu
Cc: khandual@linux.vnet.ibm.com
Cc: dsahern@gmail.com
Link: http://lkml.kernel.org/r/1328826068-11713-16-git-send-email-eranian@google.comSigned-off-by: default avatarIngo Molnar <mingo@elte.hu>
      cb5d7699
    • Roberto Agostino Vitillo's avatar
      perf report: Add support for taken branch sampling · b50311dc
      Roberto Agostino Vitillo authored 
      This patch adds support for taken branch sampling, i.e, the
PERF_SAMPLE_BRANCH_STACK feature to perf report. In other
words, to display histograms based on taken branches rather
than executed instructions addresses.

The new option is called -b and it takes no argument. To
generate meaningful output, the perf.data must have been
obtained using perf record -b xxx ... where xxx is a branch
filter option.

The output shows symbols, modules, sorted by 'who branches
where' the most often. The percentages reported in the first
column refer to the total number of branches captured and
not the usual number of samples.

Here is a quick example.
Here branchy is simple test program which looks as follows:

void f2(void)
{}
void f3(void)
{}
void f1(unsigned long n)
{
  if (n & 1UL)
    f2();
  else
    f3();
}
int main(void)
{
  unsigned long i;

  for (i=0; i < N; i++)
   f1(i);
  return 0;
}

Here is the output captured on Nehalem, if we are
only interested in user level function calls.

$ perf record -b any_call,u -e cycles:u branchy

$ perf report -b --sort=symbol
    52.34%  [.] main                   [.] f1
    24.04%  [.] f1                     [.] f3
    23.60%  [.] f1                     [.] f2
     0.01%  [k] _IO_new_file_xsputn    [k] _IO_file_overflow
     0.01%  [k] _IO_vfprintf_internal  [k] _IO_new_file_xsputn
     0.01%  [k] _IO_vfprintf_internal  [k] strchrnul
     0.01%  [k] __printf               [k] _IO_vfprintf_internal
     0.01%  [k] main                   [k] __printf

About half (52%) of the call branches captured are from main()
-> f1(). The second half (24%+23%) is split in two equal shares
between f1() -> f2(), f1() ->f3(). The output is as expected
given the code.

It should be noted, that using -b in perf record does not
eliminate information in the perf.data file. Consequently, a
typical profile can also be obtained by perf report by simply
not using its -b option.

It is possible to sort on branch related columns:

   - dso_from, symbol_from
   - dso_to, symbol_to
   - mispredict
Signed-off-by: default avatarRoberto Agostino Vitillo <ravitillo@lbl.gov>
Signed-off-by: default avatarStephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: robert.richter@amd.com
Cc: ming.m.lin@intel.com
Cc: andi@firstfloor.org
Cc: asharma@fb.com
Cc: vweaver1@eecs.utk.edu
Cc: khandual@linux.vnet.ibm.com
Cc: dsahern@gmail.com
Link: http://lkml.kernel.org/r/1328826068-11713-14-git-send-email-eranian@google.comSigned-off-by: default avatarIngo Molnar <mingo@elte.hu>
      b50311dc
    • Roberto Agostino Vitillo's avatar
      perf record: Add support for sampling taken branch · bdfebd84
      Roberto Agostino Vitillo authored 
      This patch adds a new option to enable taken branch stack
sampling, i.e., leverage the PERF_SAMPLE_BRANCH_STACK feature
of perf_events.

There is a new option to active this mode: -b.
It is possible to pass a set of filters to select the type of
branches to sample.

The following filters are available:

 - any : any type of branches
 - any_call : any function call or system call
 - any_ret : any function return or system call return
 - any_ind : any indirect branch
 - u:  only when the branch target is at the user level
 - k: only when the branch target is in the kernel
 - hv: only when the branch target is in the hypervisor

Filters can be combined by passing a comma separated list
to the option:

$ perf record -b any_call,u -e cycles:u branchy
Signed-off-by: default avatarRoberto Agostino Vitillo <ravitillo@lbl.gov>
Signed-off-by: default avatarStephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: robert.richter@amd.com
Cc: ming.m.lin@intel.com
Cc: andi@firstfloor.org
Cc: asharma@fb.com
Cc: vweaver1@eecs.utk.edu
Cc: khandual@linux.vnet.ibm.com
Cc: dsahern@gmail.com
Link: http://lkml.kernel.org/r/1328826068-11713-13-git-send-email-eranian@google.comSigned-off-by: default avatarIngo Molnar <mingo@elte.hu>
      bdfebd84
    • Roberto Agostino Vitillo's avatar
      perf tools: Add code to support PERF_SAMPLE_BRANCH_STACK · b5387528
      Roberto Agostino Vitillo authored 
      This patch adds:

 - ability to parse samples with PERF_SAMPLE_BRANCH_STACK
 - sort on branches (dso_from, symbol_from, dso_to, symbol_to, mispredict)
 - build histograms on branches
Signed-off-by: default avatarRoberto Agostino Vitillo <ravitillo@lbl.gov>
Signed-off-by: default avatarStephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: robert.richter@amd.com
Cc: ming.m.lin@intel.com
Cc: andi@firstfloor.org
Cc: asharma@fb.com
Cc: vweaver1@eecs.utk.edu
Cc: khandual@linux.vnet.ibm.com
Cc: dsahern@gmail.com
Link: http://lkml.kernel.org/r/1328826068-11713-12-git-send-email-eranian@google.comSigned-off-by: default avatarIngo Molnar <mingo@elte.hu>
      b5387528
  3. 05 Mar, 2012 12 commits
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  7. 02 Mar, 2012 2 commits
  9. 29 Feb, 2012 4 commits
  11. 28 Feb, 2012 3 commits
  13. 27 Feb, 2012 11 commits
  15. 26 Feb, 2012 1 commit
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