Re: 2.6.0-test8/test9 io scheduler needs tuning?

[Michael Frank <mhf@linuxmail.org>]

On Tuesday 28 October 2003 11:54, Nick Piggin wrote:
> 
> Nigel Cunningham wrote:
> 
> >As you rightly guessed, I was forgetting there are now 1000 jiffies per
> >second.
> >
> >With your patch applied, I can achieve something close to 2.4
> >performance, but only if I set the limit on the number of pages to
> >submit at one time quite high. If I set it to 3000, I can get 20107 4K
> >pages written in 5267 jiffies (14MB/s) and can read them back at resume
> >time (so cache is not a factor) in 4620 jiffies (16MB/s). In 2.4, I
> >normally set the limit on async commits to 100, and achieve the same
> >performance. 100 here makes it very jerky and much slower.
> >
> >Could there be some timeout value on BIOs that I might be able to
> >tweak/disable during suspend?
> >
> 
> Try setting /sys/block/xxx/queue/iosched/antic_expire to 0 on your
> device under IO and see how it goes. That shouldn't be causing the
> problem though, especially as you are mostly writing I think?
> 
> Otherwise might possibly be the queue plugging stuff, or maybe a
> regression in the disk driver.
> 

Haven't done much of 2.6 swsusp testing due to the little diversion
with the scheduler, however I did notice one of those dreaded DMA 
timeouts with the SIS chipset again.



Regards
Michael