Re: [PATCH RFC 1/1] perf,tool: partial callgrap and time support

From: Jiri Olsa
Date: Tue Jun 30 2015 - 08:35:17 EST


On Sun, Jun 28, 2015 at 01:47:21PM -0400, kan.liang@xxxxxxxxx wrote:
> From: Kan Liang <kan.liang@xxxxxxxxx>
>
> When multiple events are sampled it may not be needed to collect
> callgraphs for all of them. The sample sites are usually nearby, and
> it's enough to collect the callgraphs on a reference event (such as
> precise cycles or precise instructions). Similarly we also don't need
> fine grained time stamps on all events, as it's enough to have time
> stamps on the regular reference events.
> This patchkit adds the ability to turn off callgraphs and time stamps
> per event. This in term can reduce sampling overhead and the size of the
> perf.data. Furthermore, it makes collecting back traces and timestamps
> possible when PEBS threshold > 1, which significantly reducing the
> sampling overhead especially for frequently occurring events
> (https://lkml.org/lkml/2015/5/10/196). For example, A slower event with
> a larger period collects back traces/timestamps. Other more events run
> fast with multi-pebs. The time stamps from the slower events can be used
> to order the faster events. Their backtraces can give the user enough
> hint to find the right spot.

SNIP

>
> 7.13% 0.03% tchain_edit [kernel.vmlinux] [k] do_nmi
> |
> ---do_nmi
> end_repeat_nmi
> f3
> f2
> f1
> main
> __libc_start_main
>
> Signed-off-by: Kan Liang <kan.liang@xxxxxxxxx>
> ---
> tools/perf/Documentation/perf-record.txt | 13 ++++++++
> tools/perf/builtin-record.c | 7 ++--
> tools/perf/perf.h | 2 ++
> tools/perf/util/evsel.c | 55 ++++++++++++++++++++++++++++++--
> tools/perf/util/parse-events.c | 33 +++++++++++++++++++
> tools/perf/util/parse-events.h | 3 ++
> tools/perf/util/parse-events.l | 3 ++
> tools/perf/util/parse-options.c | 2 ++
> tools/perf/util/parse-options.h | 4 +++
> 9 files changed, 116 insertions(+), 6 deletions(-)

could you please break up this patch into:
- parse option changes (+description what are those new macros good for)
- callchains terms addition
- time term addition

thanks,
jirka
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