Re: Interesting pentium-memcpy results

Benjamin Saller Bender (
Mon, 28 Jul 1997 13:04:55 -0400

Chris Evans <> writes:
>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)

>It does however show us that there still is performance to be gained. I
>presume the process creation test will be using fork() which does a lot of
>memcpy'ing of various process credentials in kernel space.
I haven't done the research to verify how well this will work under
Linux, but for large a memcpy on the P5 we may wanna consider using the FP
unit using double precision read and writes. I have sample code if anyone is
Benjamin Saller Bender 			<>
AppliedTheory Communications		Software Engineering Group               Sentio aliquos togatos contra me conspirare.