Re: benchmark of the new buffer hash

Andrea Arcangeli (andrea@suse.de)
Sat, 30 Oct 1999 23:26:01 +0200 (CEST)


On Sat, 30 Oct 1999, Manfred Spraul wrote:

>Have you thought about using a simple "sleep(1)"? This will synchonize

Yes this is a good idea of course ;). I only wanted a figure of the
numbers and so I didn't bothered to do all the stuff necessary for a very
precise bench.

>I've attached a modified version: (Pentium II/350 and Amd K6/200 (*))
>* hash13: 16 / 13 cpu ticks
>* hash14pre: 46 / 33 cpu ticks
>
>(*) the K6 values vary, it seems the benchmark cannot force all cpu
>caches into the 'hot' state. These are the lowest values.

There is a better way than the sleep one: in 2.2.x on i386 you can iopl(2)
and asm("cli" :: ) by hand to do a precise bench. On 2.3.x you'll have to
boot with the nonmi option to achieve the same.

Andrea

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