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authorPeter Zijlstra <[email protected]>2011-04-22 13:39:56 +0200
committerIngo Molnar <[email protected]>2011-04-22 13:50:27 +0200
commitf4929bd37208540c2c6f416e9035ff1938f2dbc6 (patch)
tree307e058a47993c91d806f8c7bb505e8afe778a27 /drivers/mtd/lpddr
parent1ea5a6afd95a4803900c97ed63a47a883ebe7b3e (diff)
perf, x86: Update/fix Intel Nehalem cache events
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 <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Arnaldo Carvalho de Melo <[email protected]> Cc: Frederic Weisbecker <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Mike Galbraith <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Stephane Eranian <[email protected]> Cc: Lin Ming <[email protected]> Cc: Cyrill Gorcunov <[email protected]> Link: http://lkml.kernel.org/n/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
Diffstat (limited to 'drivers/mtd/lpddr')
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