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

Michael Stone
2006-05-26T00:48:24Z

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