diff options
| author | Peter Zijlstra <[email protected]> | 2011-04-22 13:39:56 +0200 | 
|---|---|---|
| committer | Ingo Molnar <[email protected]> | 2011-04-22 13:50:27 +0200 | 
| commit | f4929bd37208540c2c6f416e9035ff1938f2dbc6 (patch) | |
| tree | 307e058a47993c91d806f8c7bb505e8afe778a27 /fs/jbd/commit.c | |
| parent | 1ea5a6afd95a4803900c97ed63a47a883ebe7b3e (diff) | |
perf, x86: Update/fix Intel Nehalem cache events
Change the Nehalem cache events to use retired memory instruction counters
(similar to Westmere), this greatly improves the provided stats.
Using:
main ()
{
        int i;
        for (i = 0; i < 1000000000; i++) {
                asm("mov (%%rsp), %%rbx;"
                    "mov %%rbx, (%%rsp);" : : : "rbx");
        }
}
We find:
 $ perf stat --repeat 10 -e instructions:u -e l1-dcache-loads:u -e l1-dcache-stores:u ./loop_1b_loads+stores
  Performance counter stats for './loop_1b_loads+stores' (10 runs):
      4,000,081,056 instructions:u           #      0.000 IPC ( +-   0.000% )
      4,999,502,846 l1-dcache-loads:u          ( +-   0.008% )
      1,000,034,832 l1-dcache-stores:u         ( +-   0.000% )
         1.565184942  seconds time elapsed   ( +-   0.005% )
The 5b is surprising - we'd expect 1b:
 $ perf stat --repeat 10 -e instructions:u -e r10b:u -e l1-dcache-stores:u ./loop_1b_loads+stores
  Performance counter stats for './loop_1b_loads+stores' (10 runs):
      4,000,081,054 instructions:u           #      0.000 IPC ( +-   0.000% )
      1,000,021,961 r10b:u                     ( +-   0.000% )
      1,000,030,951 l1-dcache-stores:u         ( +-   0.000% )
         1.565055422  seconds time elapsed   ( +-   0.003% )
Which this patch thus fixes.
Signed-off-by: Peter Zijlstra <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Lin Ming <[email protected]>
Cc: Cyrill Gorcunov <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
Diffstat (limited to 'fs/jbd/commit.c')
0 files changed, 0 insertions, 0 deletions