Hardware performance events are not counted by "perf" in a 2.6.31.12 KVM guest
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From: Naresh Rapolu on 26 Mar 2010 22:10 Hello, "perf" tool does not count hardware performance events ( cache misses etc) in a KVM guest ( Ubuntu 9.10 karmic, 2.6.31-14-generic kernel) on Xeon 5530 quad-core. The host is 2.6.28 kernel , Ubuntu 8.04 LTS, Hardy. readfile.sh reads in a large file (1430 lines), which should cause cache-misses. root(a)multicore4-vm3:/usr/src/linux-2.6.31.12/tools/perf# ./perf stat -r 5 -- bash readfile.sh Performance counter stats for 'bash readfile.sh' (5 runs): 11002.207467 task-clock-msecs # 1.042 CPUs ( +- 10.834% ) 3480 context-switches # 0.000 M/sec ( +- 19.017% ) 2238 CPU-migrations # 0.000 M/sec ( +- 29.488% ) 482299 page-faults # 0.044 M/sec ( +- 0.141% ) 0 cycles # 0.000 M/sec ( +- nan% ) 0 instructions # nan IPC ( +- nan% ) 0 cache-references # 0.000 M/sec ( +- nan% ) 0 cache-misses # 0.000 M/sec ( +- nan% ) 10.560510393 seconds time elapsed ( +- 11.401% ) Do I need to make some configuration changes to enable hardware events ? A similar question was posted recently here : http://lkml.org/lkml/2010/3/18/342 but no response ! Any help would be greatly appreciated. Thanks, Naresh Rapolu. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |