Re: [resent PATCH] Re: very slow parallel read performance

Mike Galbraith
2001-08-28T05:01:39Z

On Tue, 28 Aug 2001, Dieter N|tzel wrote:

> * readahead do not show dramatic differences
> * killall -STOP kupdated DO
>
> Yes, I know it is dangerous to stop kupdated but my disk show heavy thrashing
> (seeks like mad) since 2.4.7ac4. killall -STOP kupdated make it smooth and
> fast, again.

Interesting.

A while back, I twiddled the flush logic in buffer.c a little and made
kupdated only handle light flushing.. stay out of the way when bdflush
is running. This and some dynamic adjustment of bdflush flushsize and
not stopping flushing right _at_ (biggie) the trigger level produced
very interesting improvements. (very marked reduction in system time
for heavy IO jobs, and large improvement in file rewrite throughput)

-Mike