Re: [RESEND] [PATCH] readahead:add blk_run_backing_dev

Ronald Moesbergen
2009-06-29T14:56:25Z

2009/6/29 Wu Fengguang <fengguang.wu@intel.com>:
> On Mon, Jun 29, 2009 at 10:43:48PM +0800, Ronald Moesbergen wrote:
>> 2009/6/29 Wu Fengguang <fengguang.wu@intel.com>:
>> > On Mon, Jun 29, 2009 at 09:13:27PM +0800, Wu Fengguang wrote:
>> >> On Mon, Jun 29, 2009 at 09:04:57PM +0800, Vladislav Bolkhovitin wrote:
>> >> > Wu Fengguang, on 06/29/2009 04:54 PM wrote:
>> >> > >
>> >> > > Why not 2.6.30? :)
>> >> >
>> >> > We started with 2.6.29, so why not complete with it (to save additional
>> >> > Ronald's effort to move on 2.6.30)?
>> >>
>> >> OK, that's fair enough.
>> >
>> > btw, I backported the 2.6.31 context readahead patches to 2.6.29, just
>> > in case it will help the SCST performance.
>> >
>> > Ronald, if you run context readahead, please make sure that the server
>> > side readahead size is bigger than the client side readahead size.
>>
>> I tried this patch on a vanilla kernel and no other patches applied,
>> but it does not seem to help. The iSCSI throughput does not go above
>> 60MB/s. (1GB in 17 seconds). I have tried several readahead settings
>> from 128KB up to 4MB and kept the server readahead at twice the client
>> readahead, but it never comes above 60MB/s. This is using SCST on the
>
> OK, thanks for the tests anyway!

You're welcome.

>> serverside and openiscsi on the client. I get much better throughput
>> (90 MB/s) when using the patches supplied with SCST, together with the
>
> What do you mean by "patches supplied with SCST"?

These:
http://scst.svn.sourceforge.net/viewvc/scst/trunk/scst/kernel/

Regards,
Ronald.