Messages in this thread | | | Date | Tue, 26 Apr 2016 18:05:00 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH/RFC v3] perf core: Allow setting up max frame stack depth via sysctl |
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Em Tue, Apr 26, 2016 at 01:02:34PM -0700, Brendan Gregg escreveu: > On Mon, Apr 25, 2016 at 5:49 PM, Brendan Gregg <brendan.d.gregg@gmail.com> wrote: > > On Mon, Apr 25, 2016 at 5:47 PM, Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com> wrote: > >> Em Mon, Apr 25, 2016 at 05:44:00PM -0700, Alexei Starovoitov escreveu: > >>> yep :) > >>> hopefully Brendan can give it another spin. > >> > >> Agreed, and I'm calling it a day anyway, Brendan, please consider > >> retesting, thanks, > > > > Will do, thanks! > > Looks good. > > I started with max depth = 512, and even that was still truncated, and > had to profile again at 1024 to capture the full stacks. Seems to > generally match the flame graph I generated with V1, which made me > want to check that I'm running the new patch, and am: > > # grep six_hundred_forty_kb /proc/kallsyms > ffffffff81c431e0 d six_hundred_forty_kb > > I was mucking around and was able to get "corrupted callchain. > skipping..." errors, but these look to be expected -- that was
Yeah, thanks for testing!
And since you talked about userspace without frame pointers, have you played with '--call-graph lbr'?
- Arnaldo
> profiling a binary (bash) that doesn't have frame pointers. Some perf > script -D output: > > 16 3204735442777 0x18f0d8 [0x2030]: PERF_RECORD_SAMPLE(IP, 0x1): > 18134/18134: 0xffffffff8118b6a4 period: 1001001 addr: 0 > ... FP chain: nr:1023 > ..... 0: ffffffffffffff80 > ..... 1: ffffffff8118b6a4 > ..... 2: ffffffff8118bc47 > ..... 3: ffffffff811d8c85 > ..... 4: ffffffff811b18f8 > ..... 5: ffffffff811b2a55 > ..... 6: ffffffff811b5ea0 > ..... 7: ffffffff810663c0 > ..... 8: ffffffff810666e0 > ..... 9: ffffffff817b9d28 > ..... 10: fffffffffffffe00 > ..... 11: 00000000004b45e2 > ..... 12: 000000000000610f > ..... 13: 0000000000006110 > ..... 14: 0000000000006111 > ..... 15: 0000000000006112 > ..... 16: 0000000000006113 > ..... 17: 0000000000006114 > ..... 18: 0000000000006115 > ..... 19: 0000000000006116 > ..... 20: 0000000000006117 > [...] > ..... 1021: 000000000000650b > ..... 1022: 000000000000650c > ... thread: bash:18134 > ...... dso: /lib/modules/4.6.0-rc5-virtual/build/vmlinux > bash 18134 [016] 3204.735442: 1001001 cpu-clock: > > Brendan
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