Messages in this thread | | | From | Andi Kleen <> | Subject | Re: [PATCH 1/2] perf: ignore LBR and offcore_rsp. | Date | Mon, 23 Jun 2014 08:56:44 -0700 |
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Peter Zijlstra <peterz@infradead.org> writes:
> > So I really hate this patch, it makes the code hideous. Also, its a > death by a thousand cuts adding endless branches in this code.
FWIW compared to the cost of a RDMSR (which is a very complex operation for the CPU) the cost of a predicted branch is nearly in the noise.
> > Also, the offcore part is retarded, just make sure extra_reg isn't set. > > As to the LBR, just make it so that we avoid calling the LBR code to > begin with; ideally without adding extra code to fast paths.
You mean check once at initialization time.
I'm not sure that would handle all cases unfortunately.
-Andi
-- ak@linux.intel.com -- Speaking for myself only
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