In message <20050228081036.GA20462@spathi.chuq.com>,
Chuck Silvers writes:

>hi folks,
>
>since my profiling experiments with the 10M Rows mysql benchmark showed that
>avoiding read-before-overwrite didn't help much at all, this morning I decided
>to go for the real solution and look into unbuffered (aka direct) I/O.
>implementing this turned out to be much easier than I expected, it only
>took a few hours to get it working.  the diff is at:
>
>	ftp://ftp.netbsd.org/pub/NetBSD/misc/chs/diff.directio

I hate to seem nagging, and I do appreciate the performance regression
tests you did with loanout.

But: if FreeBSD-4 doesn't need direct I/O, why do we need it?  Could
the poor performance be symptomatic of something else -- e.g., by
analogy to the relative NFS performance of NetBSD-2.0 and Free-BSD4,
maybe we just lack sufficient read-ahead?

Does your directio patch already show a big improvement in the 10M
Rows mysql benchmark?