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Re: [PATCH v2] Saving a few cycles, part 3/3

From: Stefan Sperling <stsp_at_elego.de>
Date: Tue, 11 May 2010 13:27:26 +0200

On Tue, May 11, 2010 at 01:36:26AM +0200, Johan Corveleyn wrote:
> As I understand your set of patches, you're mainly focusing on saving
> cpu cycles, and not on avoiding I/O where possible (unless I'm missing
> something). Maybe some of the low- or high-level algorithms in the
> back-end can be reworked a bit to reduce the amount of I/O? Or maybe
> some clever caching can avoid some file accesses?

In general, I think trying to work around I/O slowness by loading
stuff into RAM (caching) is a bad idea. You're just taking away memory
from the OS buffer cache if you do this. A good buffer cache in the OS
should make open/close/seek fast. (So don't run a windows server if
you can avoid it.)

The only point where it's worth thinking about optimizing I/O
access is when you get to clustered, distributed storage, because
at that point every I/O request translated into a network packet.

Received on 2010-05-11 13:28:03 CEST

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