Re: [Linux-ia64] VHPT performance

From: Christian Hildner <christian.hildner_at_hob.de>
Date: 2002-03-08 21:26:33
David Mosberger schrieb:

> >>>>> On Fri, 08 Mar 2002 08:50:15 +0100, Christian Hildner <christian.hildner@hob.de> said:
>
>   Christian> Could you please try with my test program to verify what
>   Christian> I found (compile with -O). The pointer increment is half
>   Christian> the page size, so TLB hit and TLB miss are changing.
>
> I think it's your program: I suspect you're measuring cache misses
> more than anything else.  Try touching a set of pages repeatedly and
> try to touch different words, such that there are no cache misses.
>
>         --david

Ok that's true. I changed my program so that before the measuring loop there comes the same loop
for filling the cache. Also I had to increase the memory size to a minimum of 128 pages because
for itanium there are 32 entries for L1-DTLB and 96 entries for L2-DTLB. Now I get values of 42
cycles with VHPT enabled and 180 cycles with VHPT disabled. This values are coming near to the
ones you found.

Christian
Received on Fri Mar 08 02:35:45 2002

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