On Wed, 2005-02-09 at 13:11, Sonny Rao wrote: > On Tue, Feb 08, 2005 at 12:38:08AM -0500, Sonny Rao wrote: > > On Mon, Feb 07, 2005 at 06:33:51PM -0700, Andreas Dilger wrote: > > > On Feb 03, 2005 15:50 -0500, Sonny Rao wrote: > > > > Well, from what I can tell, my patch doesn't seem to make much of a > > > > difference in write throughput other than allowing multi-page bios to > > > > be sent down and cutting down on buffer_head usage. > > > > > > Even if it doesn't make a difference in performance, it might reduce the > > > CPU usage. Did you check that at all? > > > > No I didn't, I'll check that out and post back. > > > > Sonny > > Ok, I take it back, on a raid device I saw a significant increase in > throughput and approximately equal cpu utilization. I was comparing > the wrong data points before.. oops. > > Sequential overwrite went from 75.6 MB/sec to 87.7 MB/sec both with an > average CPU utilization of 73% for both. > > So, I see a 16% improvement in throughput for this test case and a > corresponding increase in efficiency. > > Although, after reading what SCT wrote about writepage and writepages > needing to have a transaction handle, in some cases, that might make > the proper writepages code significantly more complex than my two-bit > hack. Still, I think it's worth it.
Yep. I hacked ext3_write_pages() to use mpage_writepages() as you did (without modifying bufferheads stuff). With the limited testing I did, I see much larger IO chunks and better throughput. So, I guess its worth doing it - i am little worried about error handling though.. Lets handle one issue at a time. First fix writepages() without bufferhead changes ? Then handle bufferheads ? I still can't figure out a way to workaround the bufferheads especially for ordered writes. Thanks, Badari - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
