Re: [reiserfs-list] Re: [resent PATCH] Re: very slow parallel read

[Hans Reiser]

Mike Galbraith wrote:
> 
> 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

Can you send us the patch, and Elena will run some tests on it?

Hans