Messages in this thread | | | Date | Mon, 6 Jan 2014 15:17:13 -0500 (EST) | From | Mikulas Patocka <> | Subject | Re: [PATCH 1/3] powernow-k6: disable cache when changing frequency |
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On Fri, 3 Jan 2014, Viresh Kumar wrote:
> On 2 January 2014 23:08, Mikulas Patocka <mpatocka@redhat.com> wrote: > > Flushing the cache and changing frequency takes approximatelly 500us. The > > patch increases policy->cpuinfo.transition_latency to that value. > > Its not about how fast caches get cleaned but how much time would > be wasted to get them filled again as same data could be required again > which is just flushed out. That would impact performance more than > flushing caches.
I didn't see any performance degradation when I tried changing the frequency manually with or without the cache flush patch - the overhead of running cpufreq (8ms) is far worse than the frequency transition itself.
Mikulas
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