https://github.com/torvalds/linux
Revision f4929bd37208540c2c6f416e9035ff1938f2dbc6 authored by Peter Zijlstra on 22 April 2011, 11:39:56 UTC, committed by Ingo Molnar on 22 April 2011, 11:50:27 UTC
Change the Nehalem cache events to use retired memory instruction counters (similar to Westmere), this greatly improves the provided stats. Using: main () { int i; for (i = 0; i < 1000000000; i++) { asm("mov (%%rsp), %%rbx;" "mov %%rbx, (%%rsp);" : : : "rbx"); } } We find: $ perf stat --repeat 10 -e instructions:u -e l1-dcache-loads:u -e l1-dcache-stores:u ./loop_1b_loads+stores Performance counter stats for './loop_1b_loads+stores' (10 runs): 4,000,081,056 instructions:u # 0.000 IPC ( +- 0.000% ) 4,999,502,846 l1-dcache-loads:u ( +- 0.008% ) 1,000,034,832 l1-dcache-stores:u ( +- 0.000% ) 1.565184942 seconds time elapsed ( +- 0.005% ) The 5b is surprising - we'd expect 1b: $ perf stat --repeat 10 -e instructions:u -e r10b:u -e l1-dcache-stores:u ./loop_1b_loads+stores Performance counter stats for './loop_1b_loads+stores' (10 runs): 4,000,081,054 instructions:u # 0.000 IPC ( +- 0.000% ) 1,000,021,961 r10b:u ( +- 0.000% ) 1,000,030,951 l1-dcache-stores:u ( +- 0.000% ) 1.565055422 seconds time elapsed ( +- 0.003% ) Which this patch thus fixes. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Stephane Eranian <eranian@google.com> Cc: Lin Ming <ming.m.lin@intel.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Link: http://lkml.kernel.org/n/tip-q9rtru7b7840tws75xzboapv@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
1 parent 1ea5a6a
Tip revision: f4929bd37208540c2c6f416e9035ff1938f2dbc6 authored by Peter Zijlstra on 22 April 2011, 11:39:56 UTC
perf, x86: Update/fix Intel Nehalem cache events
perf, x86: Update/fix Intel Nehalem cache events
Tip revision: f4929bd
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crypto | ||
drivers | ||
firmware | ||
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include | ||
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ipc | ||
kernel | ||
lib | ||
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net | ||
samples | ||
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COPYING | -rw-r--r-- | 18.3 KB |
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Kbuild | -rw-r--r-- | 2.4 KB |
Kconfig | -rw-r--r-- | 252 bytes |
MAINTAINERS | -rw-r--r-- | 188.3 KB |
Makefile | -rw-r--r-- | 51.1 KB |
README | -rw-r--r-- | 17.1 KB |
REPORTING-BUGS | -rw-r--r-- | 3.3 KB |
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