Messages in this thread |  | | Date | Thu, 11 Jan 2001 16:26:54 +0100 (CET) | From | Tobias Ringstrom <> | Subject | Re: Benchmarking 2.2 and 2.4 using hdparm and dbench 1.1 |
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[regarding the buffer cache hash size and bad performance on machines with little memory... (<32MB)]
On Tue, 9 Jan 2001, Anton Blanchard wrote: > > Where is the size defined, and is it easy to modify? > > Look in fs/buffer.c:buffer_init()
I experimented some, and increasing the huffer cache hash to the 2.2 levels helped a lot, especially for 16 MB memory. The difference is huge, 64 kB in 2.2 vs 1 kB in 2.4 for a 32 MB memory machine.
> I havent done any testing on slow hardware and the high end stuff is > definitely performing better in 2.4, but I agree we shouldn't forget > about the slower stuff.
Being able to tune the machine for both high and low end systems is neccessary, and if Linux can tune itself, that's of course the best.
> Narrowing down where the problem is would help. My guess is it is a TCP > problem, can you check if it is performing worse in your case? (eg ftp > something against 2.2 and 2.4)
Nope, TCP performance seems more or less unchanged. I will keep investigating, and get back when I have more info.
/Tobias
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