Date: Tue, 6 Jun 2000 09:27:21 +0900 (JST) From: "Daniel C. Sobral" <dcs@newsguy.com> To: "Zach Brown" <zab@zabbo.net> Cc: hackers@FreeBSD.ORG Subject: Re: Optimization Message-ID: <200006060027.JAA00822@daniel.sobral> In-Reply-To: <20000605170742.C9146@mrnutty.zabbo.net> from "Zach Brown" at "Jun 5, 2000 05:07:42 pm"
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Unheedful of thy elder's warnings, Zach Brown wrote: > > Don't forget the effects of caching. If x/y are always referenced > together, and memory is slow slow slow (on, say, any processor made in > the last few years) then the cost of unmushing the data in the cpu > could be much cheaper than the cost of going to memory to get x and y > from different tables. It all depends on access patterns. That's why I used a table of structure instead of two tables. The second fetch on the alternative A is all but garanteed to be cached. > do some benchmarking. extra credit for using cpu counters to get Real > Numbers :) http://www.fz-juelich.de/zam/PCL/doc/pcl/pcl.html Benchmarks can be deceiving if you don't know the issues behind the code. -- Daniel C. Sobral (8-DCS) dcs@newsguy.com dcs@freebsd.org capo@there.is.no.bsdconspiracy.net The smallest worm will turn being trodden on. -- William Shakespeare, "Henry VI" To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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