Messages in this thread | | | Date | Fri, 24 Mar 2017 13:07:42 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [PATCH 0/3]measure SMI cost |
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On Fri, 24 Mar 2017, Andi Kleen wrote:
> > > A new --smi-cost mode in perf stat is implemented to measure the SMI cost > > > by calculating cycles and aperf results. In practice, the percentages of > > > SMI cycles should be more useful than absolute value. > > > > That's only true for performance oriented analysis, but for analyzing the > > root cause of latencies the actual cycles are definitely interesting. > > perf stat also prints the absolute cycles of course (unless you do --metric-only)
So much for the theory. From the patch:
+ if (!force_metric_only) + metric_only = true;
> It cannot print individual cycles (per SMI occurrence), the only > way to do that would be to poll constantly.
I'm well aware of that.
Thanks,
tglx
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