Re: [PATCH 00/33] Adaptive read-ahead V12

From: Michael Stone
Date: Thu May 25 2006 - 20:47:36 EST


On Thu, May 25, 2006 at 03:01:49PM -0700, Andrew Morton wrote:
If the developers of that program want to squeeze the last 5% out of it
then sure, I'd expect them to use such OS-provided I/O scheduling
facilities.

Maybe, if we were talking about squeezing the last 5%. But all applications should be required to greatly complicate their IO routines for the last 30%? To reimplement something the kernel already does (at least to some degree), as opposed to making the kernel implementation better? "Is that dumb, or what?" :-)

Database developers do that sort of thing all the time.

Even the oracle people seem to have figured out they were doing too much that's properly the responsibility of the OS and creating a maintenance and portability nightmare.

Mike Stone
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