Messages in this thread | | | From | Andi Kleen <> | Subject | Add fine grained sampled metrics for perf script | Date | Thu, 9 Nov 2017 06:55:23 -0800 |
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This patch kit adds perf script support for computing metrics for sampled groups. This allows much more fine grained metrics measurement than perf stat allows.
The patchkit contains one extra bug fix (add missing documentation)
This allows things like fine grained IPC tracking.
Note that the metric is still averaged over the sampling period, it is not just for the sampling point.
For example to sample IPC:
$ perf record -e '{ref-cycles,cycles,instructions}:S' -a sleep 1 $ perf script -F metric,ip,sym,time,cpu,comm ... alsa-sink-ALC32 [000] 42815.856074: 7fd65937d6cc [unknown] alsa-sink-ALC32 [000] 42815.856074: 7fd65937d6cc [unknown] alsa-sink-ALC32 [000] 42815.856074: 7fd65937d6cc [unknown] alsa-sink-ALC32 [000] 42815.856074: metric: 0.13 insn per cycle swapper [000] 42815.857961: ffffffff81655df0 __schedule swapper [000] 42815.857961: ffffffff81655df0 __schedule :1 swapper [000] 42815.857961: ffffffff81655df0 __schedule swapper [000] 42815.857961: metric: 0.23 insn per cycle qemu-system-x86 [000] 42815.858130: ffffffff8165ad0e _raw_spin_unlock_irqrestore qemu-system-x86 [000] 42815.858130: ffffffff8165ad0e _raw_spin_unlock_irqrestore qemu-system-x86 [000] 42815.858130: ffffffff8165ad0e _raw_spin_unlock_irqrestore qemu-system-x86 [000] 42815.858130: metric: 0.46 insn per cycle :4972 [000] 42815.858312: ffffffffa080e5f2 vmx_vcpu_run :4972 [000] 42815.858312: ffffffffa080e5f2 vmx_vcpu_run :4972 [000] 42815.858312: ffffffffa080e5f2 vmx_vcpu_run :4972 [000] 42815.858312: metric: 0.45 insn per cycle
TopDown:
Note this requires disabling SMT if you have it enabled (e.g. by offlining the extra CPUs), because SMT would require sampling per core, which is not supported.
$ perf record -e '{ref-cycles,topdown-fetch-bubbles,topdown-recovery-bubbles,\ topdown-slots-retired,topdown-total-slots,topdown-slots-issued}:S' -a sleep 1 $ perf script --header -I -F cpu,ip,sym,event,metric,period ... [000] 121108 ref-cycles: ffffffff8165222e copy_user_enhanced_fast_string [000] 190350 topdown-fetch-bubbles: ffffffff8165222e copy_user_enhanced_fast_string [000] 2055 topdown-recovery-bubbles: ffffffff8165222e copy_user_enhanced_fast_string [000] 148729 topdown-slots-retired: ffffffff8165222e copy_user_enhanced_fast_string [000] 144324 topdown-total-slots: ffffffff8165222e copy_user_enhanced_fast_string [000] 160852 topdown-slots-issued: ffffffff8165222e copy_user_enhanced_fast_string [000] metric: 33.0% frontend bound [000] metric: 3.5% bad speculation [000] metric: 25.8% retiring [000] metric: 37.7% backend bound [000] 112112 ref-cycles: ffffffff8165aec8 _raw_spin_lock_irqsave [000] 357222 topdown-fetch-bubbles: ffffffff8165aec8 _raw_spin_lock_irqsave [000] 3325 topdown-recovery-bubbles: ffffffff8165aec8 _raw_spin_lock_irqsave [000] 323553 topdown-slots-retired: ffffffff8165aec8 _raw_spin_lock_irqsave [000] 270507 topdown-total-slots: ffffffff8165aec8 _raw_spin_lock_irqsave [000] 341226 topdown-slots-issued: ffffffff8165aec8 _raw_spin_lock_irqsave [000] metric: 33.0% frontend bound [000] metric: 2.9% bad speculation [000] metric: 29.9% retiring [000] metric: 34.2% backend bound
Git tree: git://git.kernel.org/pub/scm/limux/kernel/git/ak/linux-misc.git perf/script-metric-1
v1: Initial post
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