Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: SURPRISING RESULTS P4 Xeon dual 2.8Ghz

Author: Gian-Carlo Pascutto

Date: 12:32:43 12/17/02

Go up one level in this thread


On December 17, 2002 at 14:47:43, Matt Taylor wrote:

>On December 17, 2002 at 14:38:22, Gian-Carlo Pascutto wrote:
>
>>On December 17, 2002 at 12:50:48, Matt Taylor wrote:
>>
>>>Actually it doesn't work like that. The CPU has an existing bandwidth of 3
>>>micro-ops/cycle.
>>
>>I was under the impression the P4 was much more limited than that
>>(don't remember the details though).
>
>1 micro-op/cycle from the decoder to the trace cache, 3 micro-ops/cycle from the
>trace cache to the execution units. They get around the former limitation by
>caching the decoded output.

Yes, this is what I remembered indeed. 8000 microops is going to be
a *tight* space to fit an entire chessprogram in.

If you're running out of that cache, there's no way to make use of the
HT, is there?

>
>>>Now, I am no parallel researcher, but even my parallel code doesn't suffer
>>>overheads so large that it can't gain from HT.
>>
>>Depends on what the problem is.
>
>You mean it depends on whether or not it's a parallel problem.

Some problems are harder to parallelize with good efficiency.

--
GCP



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.