[PATCH 0/8][RFC] IO latency/throughput fixes

From: Jens Axboe
Date: Mon Apr 06 2009 - 08:48:41 EST


Hi,

This is a set of patches that I worked on today in the hopes
of furthering the latency goals and at least fixing some of
the write regression with fwrite + fsync that current -git
is suffering from.

I haven't done any latency tests yet, I'm just tossing this
out there so we can collaborate on improving things. What I
did test was the silly fwrite() + fsync() loop test, which
is a LOT slower in current -git that it used to be. The test
is basically:

while (nr--) {
f = fopen();
fprintf(f, "Some data here\n");
fsync(fileno(f));
fclose(f);
}

which (for nr == 2000) takes 16 seconds in -git, completes
in 0.9s with the patches.

--
Jens Axboe

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