Messages in this thread | | | Date | Mon, 27 Apr 2020 12:10:44 +0200 | From | Jiri Olsa <> | Subject | Re: [PATCH v3 0/7] perf: Stream comparison |
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On Mon, Apr 20, 2020 at 09:04:44AM +0800, Jin Yao wrote:
SNIP
> compute_flag div.c:25 compute_flag div.c:25 > compute_flag div.c:22 compute_flag div.c:22 > main div.c:40 main div.c:40 > main div.c:40 main div.c:40 > main div.c:39 main div.c:39* > > [ Hot chains in old perf data only ] > > hot chain 1: > cycles: 2, hits: 4.08% > -------------------------- > main div.c:42 > compute_flag div.c:28 > > [ Hot chains in new perf data only ] > > hot chain 1: > cycles: 36, hits: 3.36% > -------------------------- > __random_r random_r.c:357 > __random random.c:293 > __random random.c:293 > __random random.c:291 > __random random.c:291 > __random random.c:291 > __random random.c:288 > rand rand.c:27 > rand rand.c:26 > rand@plt > rand@plt > compute_flag div.c:25 > compute_flag div.c:22 > main div.c:40 > main div.c:40 > > Now we can see, following streams pair is moved to another section > "[ Hot chains in old perf data but source line changed (*) in new perf data ]" > > cycles: 1, hits: 26.80% cycles: 1, hits: 27.30% > --------------------------- -------------------------- > main div.c:39 main div.c:39* > main div.c:44 main div.c:44 >
so I tried following:
# ./perf record -e cycles:u -b ./perf bench sched pipe # ./perf record -e cycles:u -b ./perf bench sched pipe # ./perf diff -f --stream --before $PWD --after $PWD >out 2>&1
and the out file looks like this:
[ Matched hot chains between old perf data and new perf data ]
[ Hot chains in old perf data but source line changed (*) in new perf data ]
[ Hot chains in old perf data only ]
hot chain 1: cycles: 0, hits: 4.20% -------------------------- 0xffffffff89c00163
hot chain 2: cycles: 0, hits: 4.11% -------------------------- 0xffffffff89c00163
hot chain 3: cycles: 0, hits: 8.22% -------------------------- 0xffffffff89c00163
hot chain 4: cycles: 0, hits: 5.54% -------------------------- 0xffffffff89c00163
hot chain 5: cycles: 0, hits: 6.10% -------------------------- 0xffffffff89c00163
[ Hot chains in new perf data only ]
hot chain 1: cycles: 0, hits: 5.21% -------------------------- 0xffffffff89c00163
hot chain 2: cycles: 0, hits: 4.79% -------------------------- 0xffffffff89c00163
hot chain 3: cycles: 0, hits: 5.44% -------------------------- 0xffffffff89c00163
hot chain 4: cycles: 0, hits: 5.50% -------------------------- 0xffffffff89c00163
hot chain 5: cycles: 0, hits: 7.14% -------------------------- 0xffffffff89c00163
I'd expected more common paths, from what I can see from 'perf report --branch-history' on bpth perf.data and perf.data.old
jirka
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