lkml.org 
[lkml]   [2021]   [Mar]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] perf annotate: Fix sample events lost in stdio mode
From
Date
Hello,

On 2021/3/6 16:28, Yang Jihong wrote:
> In hist__find_annotations function, since have a hist_entry per IP for the same
> symbol, we free notes->src to signal already processed this symbol in stdio mode;
> when annotate, entry will skipped if notes->src is NULL to avoid repeated output.
>
> However, there is a problem, for example, run the following command:
>
> # perf record -e branch-misses -e branch-instructions -a sleep 1
>
> perf.data file contains different types of sample event.
>
> If the same IP sample event exists in branch-misses and branch-instructions,
> this event uses the same symbol. When annotate branch-misses events, notes->src
> corresponding to this event is set to null, as a result, when annotate
> branch-instructions events, this event is skipped and no annotate is output.
>
> Solution of this patch is to add a u8 member to struct sym_hist and use a bit to
> indicate whether the symbol has been processed.
> Because different types of event correspond to different sym_hist, no conflict
> occurs.
> ---
> tools/perf/builtin-annotate.c | 22 ++++++++++++++--------
> tools/perf/util/annotate.h | 4 ++++
> 2 files changed, 18 insertions(+), 8 deletions(-)
>
> diff --git a/tools/perf/builtin-annotate.c b/tools/perf/builtin-annotate.c
> index a23ba6bb99b6..c8c67892ae82 100644
> --- a/tools/perf/builtin-annotate.c
> +++ b/tools/perf/builtin-annotate.c
> @@ -372,15 +372,21 @@ static void hists__find_annotations(struct hists *hists,
> if (next != NULL)
> nd = next;
> } else {
> - hist_entry__tty_annotate(he, evsel, ann);
> + struct sym_hist *h = annotated_source__histogram(notes->src,
> + evsel->idx);
> +
> + if (h->processed == 0) {
> + hist_entry__tty_annotate(he, evsel, ann);
> +
> + /*
> + * Since we have a hist_entry per IP for the same
> + * symbol, set processed flag of evsel in sym_hist
> + * to signal we already processed this symbol.
> + */
> + h->processed = 1;
> + }
> +
> nd = rb_next(nd);
> - /*
> - * Since we have a hist_entry per IP for the same
> - * symbol, free he->ms.sym->src to signal we already
> - * processed this symbol.
> - */
> - zfree(&notes->src->cycles_hist);
> - zfree(&notes->src);
> }
> }
> }
> diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h
> index 096cdaf21b01..89872bfdc958 100644
> --- a/tools/perf/util/annotate.h
> +++ b/tools/perf/util/annotate.h
> @@ -228,6 +228,10 @@ void symbol__calc_percent(struct symbol *sym, struct evsel *evsel);
> struct sym_hist {
> u64 nr_samples;
> u64 period;
> +
> + u8 processed : 1, /* whether symbol has been processed, used for annotate */
> + __reserved : 7;
> +
> struct sym_hist_entry addr[];
> };
>
>
Please check whether this solution is feasible, look forward to your review.

Thanks,
Yang

\
 
 \ /
  Last update: 2021-03-11 09:49    [W:0.071 / U:0.044 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site