Em Wed, Oct 07, 2015 at 02:31:20PM +0200, Jesper Dangaard Brouer escreveu: > On Tue, 6 Oct 2015 01:07:03 +0200 > Jesper Dangaard Brouer <brouer@xxxxxxxxxx> wrote: > > (trimmed Cc list a little) > > > > On Mon, 5 Oct 2015 14:20:45 -0700 Andi Kleen <ak@xxxxxxxxxxxxxxx> wrote: > > > > > > My only problem left, is I want a perf measurement that pinpoint these > > > > kind of spots. The difference in L1-icache-load-misses were significant > > > > (1,278,276 vs 2,719,158). I tried to somehow perf record this with > > > > different perf events without being able to pinpoint the location (even > > > > though I know the spot now). Even tried Andi's ocperf.py... maybe he > > > > will know what event I should try? > > > > > > Run pmu-tools toplev.py -l3 with --show-sample. It tells you what the > > > bottle neck is and what to sample for if there is a suitable event and > > > even prints the command line. > > > > > > https://github.com/andikleen/pmu-tools/wiki/toplev-manual#sampling-with-toplev > > > > > > > My result from (IP-forward flow hitting CPU 0): > > $ sudo ./toplev.py -I 1000 -l3 -a --show-sample --core C0 > > > > So, what does this tell me?: > > > > C0 BAD Bad_Speculation: 0.00 % [ 5.50%] > > C0 BE Backend_Bound: 100.00 % [ 5.50%] > > C0 BE/Mem Backend_Bound.Memory_Bound: 53.06 % [ 5.50%] > > C0 BE/Core Backend_Bound.Core_Bound: 46.94 % [ 5.50%] > > C0-T0 FE Frontend_Bound.Frontend_Latency.Branch_Resteers: 5.42 % [ 5.50%] > > C0-T0 BE/Mem Backend_Bound.Memory_Bound.L1_Bound: 54.51 % [ 5.50%] > > C0-T0 BE/Core Backend_Bound.Core_Bound.Ports_Utilization: 20.99 % [ 5.60%] > > C0-T0 CPU utilization: 1.00 CPUs [100.00%] > > C0-T1 FE Frontend_Bound.Frontend_Latency.Branch_Resteers: 6.04 % [ 5.50%] > > C0-T1 CPU utilization: 1.00 CPUs [100.00%] > > Reading: https://github.com/andikleen/pmu-tools/wiki/toplev-manual > Helped me understand most of above. > > My specific CPU (i7-4790K @ 4.00GHz) unfortunately seems to have > limited "Frontend" support. E.g. > > # perf record -g -a -e stalled-cycles-frontend > Error: > The stalled-cycles-frontend event is not supported. > > And AFAIK icache misses are part of "frontend". > > > > Unfortunately the perf command it gives me fails with: > > "invalid or unsupported event". > > > > Perf command: > > > > sudo ./ocperf.py record -g -e \ > cpu/event=0xc5,umask=0x0,name=Branch_Resteers_BR_MISP_RETIRED_ALL_BRANCHES:pp,period=400009/pp,\ > cpu/event=0xd,umask=0x3,cmask=1,name=Bad_Speculation_INT_MISC_RECOVERY_CYCLES,period=2000003/,\ > cpu/event=0xd1,umask=0x1,name=L1_Bound_MEM_LOAD_UOPS_RETIRED_L1_HIT:pp,period=2000003/pp,\ > cpu/event=0xd1,umask=0x40,name=L1_Bound_MEM_LOAD_UOPS_RETIRED_HIT_LFB:pp,period=100003/pp \ > -C 0,4 -a > > I fixed the problem with this perf command by removing the ":pp" part. > Perhaps your tool need to fix that? > > A working command line looks like this: > > sudo ./ocperf.py record -g -e \ > cpu/event=0xc5,umask=0x0,name=Branch_Resteers_BR_MISP_RETIRED_ALL_BRANCHES,period=400009/pp,\ > cpu/event=0xd,umask=0x3,cmask=1,name=Bad_Speculation_INT_MISC_RECOVERY_CYCLES,period=2000003/,\ > cpu/event=0xd1,umask=0x1,name=L1_Bound_MEM_LOAD_UOPS_RETIRED_L1_HIT,period=2000003/pp,\ > cpu/event=0xd1,umask=0x40,name=L1_Bound_MEM_LOAD_UOPS_RETIRED_HIT_LFB,period=100003/pp \ > -C 0,4 -a There is a recent patch that may help here, see below, but maybe its just a matter of removing that :pp, as it ends with a /pp anyway, no need to state that twice :) With the patch below all those /pp would be replaced with /P. - Arnaldo https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git/commit/tools/perf?id=7f94af7a489fada17d28cc60e8f4409ce216bd6d ---------------------------------------------------------------------- perf tools: Introduce 'P' modifier to request max precision The 'P' will cause the event to get maximum possible detected precise level. Following record: $ perf record -e cycles:P ... will detect maximum precise level for 'cycles' event and use it. ---------------------------------------------------------------------- - Arnaldo -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>