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SubjectRe: [RFC 0/3] perf tools: Show time info (v1)
On 12/02/2013 08:53 AM, Namhyung Kim wrote:
> Sometimes users might want to see time information along with the
> performance result but the perf cannot provide it currently.
>
> In this patchset, I added such feature using sample->time. When the
> perf processes sample events, it calculate time info and update last
> timestamp. It keeps the last timestamp for each evsel (and for each
> cpu if it's a per-cpu session).
>
> It guesses whether a session is per-cpu if it found PERF_SAMPLE_CPU in
> a evsel->attr.sample_type since I couldn't find a better way. However
> it'll have a trouble if used with tracepoint events since they require
> the cpu info in the sample_type even for the per-thread sessions.
>
> The sample time will usually be proportional to the overhead but
> sometimes it show a different result especially in idle state.
>
> With this patch, perf report can show time information in the header
> (on --stdio output only for now) and a new column which can be enabled
> by --show-time-info option.
>
> $ perf record -- perf bench sched messaging
> $ perf report --stdio --show-time-info
>
> # Samples: 10K of event 'cycles'
> # Event count (approx.): 5168954556
> # Total sampling time : 0.179102 (sec) <--- here
> #
> # Overhead Time Command Shared Object Symbol
> # ........ .......... ............... .................. ............................
> #
> 6.59% 0.006093 sched-messaging [unknown] [.] 0x0000003153ebc7ed
> 4.81% 0.005354 sched-messaging [kernel.kallsyms] [k] copy_user_generic_string
> 3.89% 0.004098 sched-messaging [kernel.kallsyms] [k] avc_has_perm_flags
> 3.77% 0.003630 sched-messaging [kernel.kallsyms] [k] unix_stream_recvmsg
> 3.37% 0.003733 sched-messaging [kernel.kallsyms] [k] _raw_spin_lock
> 2.97% 0.003489 sched-messaging [kernel.kallsyms] [k] _raw_spin_lock_irqsave
> 2.73% 0.002615 sched-messaging [kernel.kallsyms] [k] __slab_free
> 2.56% 0.002392 sched-messaging [kernel.kallsyms] [k] page_fault
> 2.45% 0.002572 sched-messaging [kernel.kallsyms] [k] sock_alloc_send_pskb
>
> I put the series on 'perf/time-sample-v1' branch in my tree:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git
>
> Any comments are welcome, thanks

Reviewed-by: Pekka Enberg <penberg@kernel.org>

for the whole series.


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