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SubjectRe: [PATCH v2 0/3] perf/core: expose thread context switch out event type to user space
On Thu, Mar 22, 2018 at 07:08:25PM +0300, Alexey Budankov wrote:
>
> Implementation of exposing context-switch-out type event as a part
> of PERF_RECORD_SWITCH[_CPU_WIDE] record.
>
> Introduced types of events assumed to be:
> a) preempt: when task->state == TASK_RUNNING
> b) yield: !preempt, encoding is done using new bit
> PERF_RECORD_MISC_SWITCH_OUT_YIELD like this:
>
> event_header->misc &=
> PERF_RECORD_MISC_SWITCH_OUT|PERF_RECORD_MISC_SWITCH_OUT_YIELD
>
> Perf tool report and script commands output has been extended to decode
> new yield bit and the updated output looks like in the examples below.
>
> The documentation has been updated to mention yield switch out events
> and its decoding symbols in perf script output.
>
> The changes have been manually tested on Fedora 27 with the patched kernel:
> git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git perf/core
>
> perf report -D -i system-wide.perf | grep _SWITCH:
>
> 1 113807080924003 0x26db26 [0x28]: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: 20495/20495
> 1 113807080925644 0x26db4e [0x28]: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 31479/31479
> 1 113807080937266 0x26db76 [0x28]: PERF_RECORD_SWITCH_CPU_WIDE OUT yield next pid/tid: 16/16
> 1 113807080938445 0x26db9e [0x28]: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 20495/20495
> 1 113807080945455 0x26dbc6 [0x28]: PERF_RECORD_SWITCH_CPU_WIDE OUT yield next pid/tid: 20495/20495
>
> perf script --show-switch-events -F +misc -I -i system-wide.perf:
>
> rcu_sched 8 [003] 113800.748548: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 0/0
> perf 31479 [000] S 113800.748548: PERF_RECORD_SWITCH_CPU_WIDE OUT next pid/tid: 59/59
> kworker/0:1 59 [000] 113800.748549: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 31479/31479
> rcu_sched 8 [003] Sy 113800.748551: PERF_RECORD_SWITCH_CPU_WIDE OUT yield next pid/tid: 0/0
> swapper 0 [003] 113800.748551: PERF_RECORD_SWITCH_CPU_WIDE IN prev pid/tid: 8/8

Acked-by: Jiri Olsa <jolsa@kernel.org>

thanks,
jirka

>
> ---
> Alexey Budankov (3):
> perf/core: store context switch out type into Perf trace
> perf report: extend raw dump (-D) out with switch out event type
> perf script: extend misc field decoding with switch out event type
>
> include/uapi/linux/perf_event.h | 5 +++++
> kernel/events/core.c | 4 +++-
> tools/include/uapi/linux/perf_event.h | 5 +++++
> tools/perf/Documentation/perf-script.txt | 17 +++++++++--------
> tools/perf/builtin-script.c | 5 ++++-
> tools/perf/util/event.c | 4 +++-
> 6 files changed, 29 insertions(+), 11 deletions(-)

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