Re: [PATCH 05/11] perf stat: Check existence of frontend/backed stalled cycles

From: Ingo Molnar
Date: Thu Mar 03 2016 - 03:28:27 EST



* Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> wrote:

> Before:
>
> $ perf stat ls
> a.patch
>
> Performance counter stats for 'ls':
>
> 0.822067 task-clock (msec) # 0.873 CPUs utilized (82.26%)
> 0 context-switches # 0.000 K/sec (82.26%)
> 0 cpu-migrations # 0.000 K/sec (82.26%)
> 125 page-faults # 0.152 M/sec (82.26%)
> 2,516,127 cycles # 3.061 GHz (82.84%)
> <not supported> stalled-cycles-frontend
> <not supported> stalled-cycles-backend
> 2,430,467 instructions # 0.97 insn per cycle (82.84%)
> 486,235 branches # 591.479 M/sec (82.84%)
> 18,389 branch-misses # 3.78% of all branches (82.84%)
>
> 0.000941536 seconds time elapsed
> $
>
> After:
>
> $ perf stat ls
> a.patch
>
> Performance counter stats for 'ls':
>
> 0.824919 task-clock (msec) # 0.893 CPUs utilized (85.47%)
> 0 context-switches # 0.000 K/sec (85.47%)
> 0 cpu-migrations # 0.000 K/sec (85.47%)
> 124 page-faults # 0.150 M/sec (85.47%)
> 2521790 cycles # 3.057 GHz (86.15%)
> 2364913 instructions # 0.94 insn per cycle (86.15%)
> 471970 branches # 572.141 M/sec (86.15%)
> 16935 branch-misses # 3.59% of all branches (86.15%)
>
> 0.000923397 seconds time elapsed
> $

Btw., the output format regression is visible in this changelog already...

Thanks,

Ingo