diff options
author | Namhyung Kim <namhyung@kernel.org> | 2021-11-06 01:56:15 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-12-08 11:04:40 +0300 |
commit | 57482dc5ac7d67bc4d1a6af85625016dae54e749 (patch) | |
tree | 140700c5cce8c3919b78d6e76c3d5b982150fceb /tools/perf | |
parent | 40e35c77448e25de86a0a908a715142919307263 (diff) | |
download | linux-57482dc5ac7d67bc4d1a6af85625016dae54e749.tar.xz |
perf sort: Fix the 'weight' sort key behavior
[ Upstream commit 784e8adda4cdb3e2510742023729851b6c08803c ]
Currently, the 'weight' field in the perf sample has latency information
for some instructions like in memory accesses. And perf tool has 'weight'
and 'local_weight' sort keys to display the info.
But it's somewhat confusing what it shows exactly. In my understanding,
'local_weight' shows a weight in a single sample, and (global) 'weight'
shows a sum of the weights in the hist_entry.
For example:
$ perf mem record -t load dd if=/dev/zero of=/dev/null bs=4k count=1M
$ perf report --stdio -n -s +local_weight
...
#
# Overhead Samples Command Shared Object Symbol Local Weight
# ........ ....... ....... ................ ......................... ............
#
21.23% 313 dd [kernel.vmlinux] [k] lockref_get_not_zero 32
12.43% 183 dd [kernel.vmlinux] [k] lockref_get_not_zero 35
11.97% 159 dd [kernel.vmlinux] [k] lockref_get_not_zero 36
10.40% 141 dd [kernel.vmlinux] [k] lockref_put_return 32
7.63% 113 dd [kernel.vmlinux] [k] lockref_get_not_zero 33
6.37% 92 dd [kernel.vmlinux] [k] lockref_get_not_zero 34
6.15% 90 dd [kernel.vmlinux] [k] lockref_put_return 33
...
So let's look at the 'lockref_get_not_zero' symbols. The top entry
shows that 313 samples were captured with 'local_weight' 32, so the
total weight should be 313 x 32 = 10016. But it's not the case:
$ perf report --stdio -n -s +local_weight,weight -S lockref_get_not_zero
...
#
# Overhead Samples Command Shared Object Local Weight Weight
# ........ ....... ....... ................ ............ ......
#
1.36% 4 dd [kernel.vmlinux] 36 144
0.47% 4 dd [kernel.vmlinux] 37 148
0.42% 4 dd [kernel.vmlinux] 32 128
0.40% 4 dd [kernel.vmlinux] 34 136
0.35% 4 dd [kernel.vmlinux] 36 144
0.34% 4 dd [kernel.vmlinux] 35 140
0.30% 4 dd [kernel.vmlinux] 36 144
0.30% 4 dd [kernel.vmlinux] 34 136
0.30% 4 dd [kernel.vmlinux] 32 128
0.30% 4 dd [kernel.vmlinux] 32 128
...
With the 'weight' sort key, it's divided to 4 samples even with the same
info ('comm', 'dso', 'sym' and 'local_weight'). I don't think this is
what we want.
I found this because of the way it aggregates the 'weight' value. Since
it's not a period, we should not add them in the he->stat. Otherwise,
two 32 'weight' entries will create a 64 'weight' entry.
After that, new 32 'weight' samples don't have a matching entry so it'd
create a new entry and make it a 64 'weight' entry again and again.
Later, they will be merged into 128 'weight' entries during the
hists__collapse_resort() with 4 samples, multiple times like above.
Let's keep the weight and display it differently. For 'local_weight',
it can show the weight as is, and for (global) 'weight' it can display
the number multiplied by the number of samples.
With this change, I can see the expected numbers.
$ perf report --stdio -n -s +local_weight,weight -S lockref_get_not_zero
...
#
# Overhead Samples Command Shared Object Local Weight Weight
# ........ ....... ....... ................ ............ .....
#
21.23% 313 dd [kernel.vmlinux] 32 10016
12.43% 183 dd [kernel.vmlinux] 35 6405
11.97% 159 dd [kernel.vmlinux] 36 5724
7.63% 113 dd [kernel.vmlinux] 33 3729
6.37% 92 dd [kernel.vmlinux] 34 3128
4.17% 59 dd [kernel.vmlinux] 37 2183
0.08% 1 dd [kernel.vmlinux] 269 269
0.08% 1 dd [kernel.vmlinux] 38 38
Reviewed-by: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20211105225617.151364-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'tools/perf')
-rw-r--r-- | tools/perf/util/hist.c | 14 | ||||
-rw-r--r-- | tools/perf/util/sort.c | 24 | ||||
-rw-r--r-- | tools/perf/util/sort.h | 2 |
3 files changed, 13 insertions, 27 deletions
diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c index 65fe65ba03c2..4e9bd7b589b1 100644 --- a/tools/perf/util/hist.c +++ b/tools/perf/util/hist.c @@ -290,11 +290,9 @@ static long hist_time(unsigned long htime) } static void he_stat__add_period(struct he_stat *he_stat, u64 period, - u64 weight, u64 ins_lat, u64 p_stage_cyc) + u64 ins_lat, u64 p_stage_cyc) { - he_stat->period += period; - he_stat->weight += weight; he_stat->nr_events += 1; he_stat->ins_lat += ins_lat; he_stat->p_stage_cyc += p_stage_cyc; @@ -308,9 +306,8 @@ static void he_stat__add_stat(struct he_stat *dest, struct he_stat *src) dest->period_guest_sys += src->period_guest_sys; dest->period_guest_us += src->period_guest_us; dest->nr_events += src->nr_events; - dest->weight += src->weight; dest->ins_lat += src->ins_lat; - dest->p_stage_cyc += src->p_stage_cyc; + dest->p_stage_cyc += src->p_stage_cyc; } static void he_stat__decay(struct he_stat *he_stat) @@ -598,7 +595,6 @@ static struct hist_entry *hists__findnew_entry(struct hists *hists, struct hist_entry *he; int64_t cmp; u64 period = entry->stat.period; - u64 weight = entry->stat.weight; u64 ins_lat = entry->stat.ins_lat; u64 p_stage_cyc = entry->stat.p_stage_cyc; bool leftmost = true; @@ -619,11 +615,11 @@ static struct hist_entry *hists__findnew_entry(struct hists *hists, if (!cmp) { if (sample_self) { - he_stat__add_period(&he->stat, period, weight, ins_lat, p_stage_cyc); + he_stat__add_period(&he->stat, period, ins_lat, p_stage_cyc); hist_entry__add_callchain_period(he, period); } if (symbol_conf.cumulate_callchain) - he_stat__add_period(he->stat_acc, period, weight, ins_lat, p_stage_cyc); + he_stat__add_period(he->stat_acc, period, ins_lat, p_stage_cyc); /* * This mem info was allocated from sample__resolve_mem @@ -733,7 +729,6 @@ __hists__add_entry(struct hists *hists, .stat = { .nr_events = 1, .period = sample->period, - .weight = sample->weight, .ins_lat = sample->ins_lat, .p_stage_cyc = sample->p_stage_cyc, }, @@ -748,6 +743,7 @@ __hists__add_entry(struct hists *hists, .raw_size = sample->raw_size, .ops = ops, .time = hist_time(sample->time), + .weight = sample->weight, }, *he = hists__findnew_entry(hists, &entry, al, sample_self); if (!hists->has_callchains && he && he->callchain_size != 0) diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c index 568a88c001c6..903f34fff27e 100644 --- a/tools/perf/util/sort.c +++ b/tools/perf/util/sort.c @@ -1325,45 +1325,35 @@ struct sort_entry sort_mispredict = { .se_width_idx = HISTC_MISPREDICT, }; -static u64 he_weight(struct hist_entry *he) -{ - return he->stat.nr_events ? he->stat.weight / he->stat.nr_events : 0; -} - static int64_t -sort__local_weight_cmp(struct hist_entry *left, struct hist_entry *right) +sort__weight_cmp(struct hist_entry *left, struct hist_entry *right) { - return he_weight(left) - he_weight(right); + return left->weight - right->weight; } static int hist_entry__local_weight_snprintf(struct hist_entry *he, char *bf, size_t size, unsigned int width) { - return repsep_snprintf(bf, size, "%-*llu", width, he_weight(he)); + return repsep_snprintf(bf, size, "%-*llu", width, he->weight); } struct sort_entry sort_local_weight = { .se_header = "Local Weight", - .se_cmp = sort__local_weight_cmp, + .se_cmp = sort__weight_cmp, .se_snprintf = hist_entry__local_weight_snprintf, .se_width_idx = HISTC_LOCAL_WEIGHT, }; -static int64_t -sort__global_weight_cmp(struct hist_entry *left, struct hist_entry *right) -{ - return left->stat.weight - right->stat.weight; -} - static int hist_entry__global_weight_snprintf(struct hist_entry *he, char *bf, size_t size, unsigned int width) { - return repsep_snprintf(bf, size, "%-*llu", width, he->stat.weight); + return repsep_snprintf(bf, size, "%-*llu", width, + he->weight * he->stat.nr_events); } struct sort_entry sort_global_weight = { .se_header = "Weight", - .se_cmp = sort__global_weight_cmp, + .se_cmp = sort__weight_cmp, .se_snprintf = hist_entry__global_weight_snprintf, .se_width_idx = HISTC_GLOBAL_WEIGHT, }; diff --git a/tools/perf/util/sort.h b/tools/perf/util/sort.h index b67c469aba79..e18b79916f63 100644 --- a/tools/perf/util/sort.h +++ b/tools/perf/util/sort.h @@ -49,7 +49,6 @@ struct he_stat { u64 period_us; u64 period_guest_sys; u64 period_guest_us; - u64 weight; u64 ins_lat; u64 p_stage_cyc; u32 nr_events; @@ -109,6 +108,7 @@ struct hist_entry { s32 socket; s32 cpu; u64 code_page_size; + u64 weight; u8 cpumode; u8 depth; |