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

[Nick Piggin]

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.


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/