On Tue, Aug 20, 2019 at 08:22:07PM +0800, Jin Yao wrote: > This patch prints the stddev and hist for the cycles diff of > program block. It can help us to understand if the cycles > is noisy or not. > > This patch is inspired by Andi Kleen's patch > https://lwn.net/Articles/600471/ > > We create new option '--cycles-hist'. > > Example: > > perf record -b ./div > perf record -b ./div > perf diff -c cycles > > # Baseline [Program Block Range] > Cycles Diff Shared Object Symbol > # ........ > ...................................................................... > ................. ............................ > # > 46.72% [div.c:40 -> > div.c:40] 0 div [.] main > 46.72% [div.c:42 -> > div.c:44] 0 div [.] main > 46.72% [div.c:42 -> > div.c:39] 0 div [.] main > 20.54% [random_r.c:357 -> > random_r.c:394] 1 libc-2.27.so [.] __random_r > 20.54% [random_r.c:357 -> > random_r.c:380] 0 libc-2.27.so [.] __random_r > 20.54% [random_r.c:388 -> > random_r.c:388] 0 libc-2.27.so [.] __random_r > 20.54% [random_r.c:388 -> > random_r.c:391] 0 libc-2.27.so [.] __random_r > 17.04% [random.c:288 -> > random.c:291] 0 libc-2.27.so [.] __random > 17.04% [random.c:291 -> > random.c:291] 0 libc-2.27.so [.] __random > 17.04% [random.c:293 -> > random.c:293] 0 libc-2.27.so [.] __random > 17.04% [random.c:295 -> > random.c:295] 0 libc-2.27.so [.] __random > 17.04% [random.c:295 -> > random.c:295] 0 libc-2.27.so [.] __random > 17.04% [random.c:298 -> > random.c:298] 0 libc-2.27.so [.] __random > 8.40% [div.c:22 -> > div.c:25] 0 div [.] compute_flag > 8.40% [div.c:27 -> > div.c:28] 0 div [.] compute_flag > 5.14% [rand.c:26 -> > rand.c:27] 0 libc-2.27.so [.] rand > 5.14% [rand.c:28 -> > rand.c:28] 0 libc-2.27.so [.] rand > 2.15% [rand@plt+0 -> > rand@plt+0] 0 div [.] rand@plt > 0.00% > [kernel.kallsyms] [k] __x86_indirect_thunk_rax > 0.00% [do_mmap+714 -> > do_mmap+732] -10 [kernel.kallsyms] [k] do_mmap > 0.00% [do_mmap+737 -> > do_mmap+765] 1 [kernel.kallsyms] [k] do_mmap > 0.00% [do_mmap+262 -> > do_mmap+299] 0 [kernel.kallsyms] [k] do_mmap > 0.00% [__x86_indirect_thunk_r15+0 -> > __x86_indirect_thunk_r15+0] 7 [kernel.kallsyms] [k] > __x86_indirect_thunk_r15 > 0.00% [native_sched_clock+0 -> > native_sched_clock+119] -1 [kernel.kallsyms] [k] native_sched_clock > 0.00% [native_write_msr+0 -> > native_write_msr+16] -13 [kernel.kallsyms] [k] native_write_msr > > When we enable the option '--cycles-hist', the output is > > perf diff -c cycles --cycles-hist > > # Baseline [Program Block Range] > Cycles Diff stddev/Hist Shared Object Symbol > # ........ > ...................................................................... > ................. ................. ............................ > # > 46.72% [div.c:40 -> > div.c:40] 0 ± 37.8% ▁█▁▁██▁█ div [.] main > 46.72% [div.c:42 -> > div.c:44] 0 ± 49.4% ▁▁▂█▂▂▂▂ div [.] main > 46.72% [div.c:42 -> > div.c:39] 0 ± 24.1% ▃█▂▄▁▃▂▁ div [.] main > 20.54% [random_r.c:357 -> > random_r.c:394] 1 ± 33.5% ▅▂▁█▃▁▂▁ libc-2.27.so [.] __random_r > 20.54% [random_r.c:357 -> > random_r.c:380] 0 ± 39.4% ▁▁█▁██▅▁ libc-2.27.so [.] __random_r > 20.54% [random_r.c:388 -> > random_r.c:388] 0 libc-2.27.so [.] __random_r > 20.54% [random_r.c:388 -> > random_r.c:391] 0 ± 41.2% ▁▃▁▂█▄▃▁ libc-2.27.so [.] __random_r > 17.04% [random.c:288 -> > random.c:291] 0 ± 48.8% ▁▁▁▁███▁ libc-2.27.so [.] __random > 17.04% [random.c:291 -> > random.c:291] 0 ±100.0% ▁█▁▁▁▁▁▁ libc-2.27.so [.] __random > 17.04% [random.c:293 -> > random.c:293] 0 ±100.0% ▁█▁▁▁▁▁▁ libc-2.27.so [.] __random > 17.04% [random.c:295 -> > random.c:295] 0 ±100.0% ▁█▁▁▁▁▁▁ libc-2.27.so [.] __random > 17.04% [random.c:295 -> > random.c:295] 0 libc-2.27.so [.] __random > 17.04% [random.c:298 -> > random.c:298] 0 ± 75.6% ▃█▁▁▁▁▁▁ libc-2.27.so [.] __random > 8.40% [div.c:22 -> > div.c:25] 0 ± 42.1% ▁▃▁▁███▁ div [.] compute_flag > 8.40% [div.c:27 -> > div.c:28] 0 ± 41.8% ██▁▁▄▁▁▄ div [.] compute_flag > 5.14% [rand.c:26 -> > rand.c:27] 0 ± 37.8% ▁▁▁████▁ libc-2.27.so [.] rand > 5.14% [rand.c:28 -> > rand.c:28] 0 libc-2.27.so [.] rand > 2.15% [rand@plt+0 -> > rand@plt+0] 0 div [.] rand@plt > 0.00% > [kernel.kallsyms] [k] __x86_indirect_thunk_rax > 0.00% [do_mmap+714 -> > do_mmap+732] -10 [kernel.kallsyms] [k] do_mmap > 0.00% [do_mmap+737 -> > do_mmap+765] 1 [kernel.kallsyms] [k] do_mmap > 0.00% [do_mmap+262 -> > do_mmap+299] 0 [kernel.kallsyms] [k] do_mmap > 0.00% [__x86_indirect_thunk_r15+0 -> > __x86_indirect_thunk_r15+0] 7 [kernel.kallsyms] [k] > __x86_indirect_thunk_r15 > 0.00% [native_sched_clock+0 -> > native_sched_clock+119] -1 ± 38.5% ▄█▁ [kernel.kallsyms] [k] > native_sched_clock > 0.00% [native_write_msr+0 -> > native_write_msr+16] -13 ± 47.1% ▁█▇▃▁▁ [kernel.kallsyms] [k] > native_write_msr > > v6: > --- > 1. Jiri provides better code for using data__hpp_register() in ui_init(). > Use this code in v6.
Reviewed-by: Jiri Olsa <jo...@kernel.org> thanks, jirka
