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 -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat Author of http://www.iptv-analyzer.org LinkedIn: http://www.linkedin.com/in/brouer -- 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>