lkml.org 
[lkml]   [2020]   [Jan]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] perf c2c: Fix sorting.
On Wed, Jan 08, 2020 at 08:30:30PM -0800, Andres Freund wrote:
> Commit 722ddfde366f ("perf tools: Fix time sorting") changed -
> correctly so - hist_entry__sort to return int64. Unfortunately several
> of the builtin-c2c.c comparison routines only happened to work due the
> cast caused by the wrong return type.
>
> This causes meaningless ordering of both the cacheline list, and the
> cacheline details page. E.g a simple
> perf c2c record -a sleep 3
> perf c2c report
> will result in cacheline table like
> =================================================
> Shared Data Cache Line Table
> =================================================
> #
> # ----------- Cacheline ---------- Total Tot ----- LLC Load Hitm ----- ---- Store Reference ---- --- Load Dram ---- LLC Total ----- Core Load Hit ----- -- LLC Load Hit --
> # Index Address Node PA cnt records Hitm Total Lcl Rmt Total L1Hit L1Miss Lcl Rmt Ld Miss Loads FB L1 L2 Llc Rmt
> # ..... .................. .... ...... ....... ....... ....... ....... ....... ....... ....... ....... ........ ........ ....... ....... ....... ....... ....... ........ ........
> #
> 0 0x7f0d27ffba00 N/A 0 52 0.12% 13 6 7 12 12 0 0 7 14 40 4 16 0 0 0
> 1 0x7f0d27ff61c0 N/A 0 6353 14.04% 1475 801 674 779 779 0 0 718 1392 5574 1299 1967 0 115 0
> 2 0x7f0d26d3ec80 N/A 0 71 0.15% 16 4 12 13 13 0 0 12 24 58 1 20 0 9 0
> 3 0x7f0d26d3ec00 N/A 0 98 0.22% 23 17 6 19 19 0 0 6 12 79 0 40 0 10 0
> i.e. with the list not being ordered by Total Hitm.
>
> Fixes: 722ddfde366f ("perf tools: Fix time sorting")
> Signed-off-by: Andres Freund <andres@anarazel.de>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Andi Kleen <ak@linux.intel.com>
> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Cc: Michael Petlan <mpetlan@redhat.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: stable@vger.kernel.org # v3.16+
> ---
> tools/perf/builtin-c2c.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
> index e69f44941aad..f2e9d2b1b913 100644
> --- a/tools/perf/builtin-c2c.c
> +++ b/tools/perf/builtin-c2c.c
> @@ -595,8 +595,8 @@ tot_hitm_cmp(struct perf_hpp_fmt *fmt __maybe_unused,
> {
> struct c2c_hist_entry *c2c_left;
> struct c2c_hist_entry *c2c_right;
> - unsigned int tot_hitm_left;
> - unsigned int tot_hitm_right;
> + uint64_t tot_hitm_left;
> + uint64_t tot_hitm_right;

that change looks right, but I can't see how that could
happened because of change in Fixes: tag

was the return statement of this function:

return tot_hitm_left - tot_hitm_right;

considered to be 'unsigned int' and then converted to int64_t,
which would treat negative 'unsigned int' as big positive 'int64_t'?

thanks,
jirka

>
> c2c_left = container_of(left, struct c2c_hist_entry, he);
> c2c_right = container_of(right, struct c2c_hist_entry, he);
> @@ -629,7 +629,8 @@ __f ## _cmp(struct perf_hpp_fmt *fmt __maybe_unused, \
> \
> c2c_left = container_of(left, struct c2c_hist_entry, he); \
> c2c_right = container_of(right, struct c2c_hist_entry, he); \
> - return c2c_left->stats.__f - c2c_right->stats.__f; \
> + return (uint64_t) c2c_left->stats.__f - \
> + (uint64_t) c2c_right->stats.__f; \
> }
>
> #define STAT_FN(__f) \
> @@ -682,7 +683,8 @@ ld_llcmiss_cmp(struct perf_hpp_fmt *fmt __maybe_unused,
> c2c_left = container_of(left, struct c2c_hist_entry, he);
> c2c_right = container_of(right, struct c2c_hist_entry, he);
>
> - return llc_miss(&c2c_left->stats) - llc_miss(&c2c_right->stats);
> + return (uint64_t) llc_miss(&c2c_left->stats) -
> + (uint64_t) llc_miss(&c2c_right->stats);
> }
>
> static uint64_t total_records(struct c2c_stats *stats)
> --
> 2.25.0.rc1
>

\
 
 \ /
  Last update: 2020-01-09 09:49    [W:0.134 / U:0.036 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site