Messages in this thread | | | Date | Tue, 29 Jul 1997 12:01:43 +0200 (MET DST) | From | Ingo Molnar <> | Subject | Re: Interesting pentium-memcpy results |
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On Tue, 29 Jul 1997, Chris Evans wrote:
> > On Mon, 28 Jul 1997, Chris Evans wrote: > > > > > I just compared 2.1.46 vs. 2.1.46+pentium memcpy patch, and interestingly > > > enough found that the UNIX byte benchmarks tended to _drop_ a fair bit, > > > with the exception of process creation and execl throughput. (Note that I > > > only ran the basic 'system' tests - TCP bandwidth etc. to be determined > > > when I find the newer benchmarks) > > > > > > This is most interesting since I used to swear by the patch.
> I'll rerun the benchmark tonight and post the results. Can anyone point me > to the most comprehensive suite that contains all the TCP > bandwidths/latencies etc. as well as pipes + process creation + file IO?
ok, one of the possible reasons might be that memcpy() is not inlined anymore ... the current (bit slower) string-operation based memcpy() inlines _very_ well. For a hot path with many get_user()'s this might show up ... although i do not know what the real reason is, this is just a guess.
-- mingo
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