Re: [Bug #13726] fio sync read 4k block size 35% regression

Wu Fengguang
2009-07-10T06:37:30Z

On Tue, Jul 07, 2009 at 02:06:42PM +0800, Zhang, Yanmin wrote:
> On Tue, 2009-07-07 at 02:01 +0200, Rafael J. Wysocki wrote:
> > This message has been generated automatically as a part of a report
> > of recent regressions.
> >
> > The following bug entry is on the current list of known regressions
> > from 2.6.30. Please verify if it still should be listed and let me know
> > (either way).
> >
> >
> > Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=13726
> > Subject : fio sync read 4k block size 35% regression
> > Submitter : Zhang, Yanmin <yanmin_zhang-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
> > Date : 2009-07-01 11:25 (6 days old)
> > First-Bad-Commit: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=51daa88ebd8e0d437289f589af29d4b39379ea76
> > References : http://lkml.org/lkml/2009/6/30/679
> > Handled-By : Wu Fengguang <fengguang.wu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> Fengguang,
>
> I'm still working on it now. The new testing against 2.6.31-rc2 is ongoing.
> fio sync/mmap read has new behavior. I did collect some data. But suddenly
> with new created data, the fio_sync_read_4k regression disappeared, while

Do you mean the fio_sync_read_4k regression disappeared because we are
collecting data with lots of printks?

> fio_mmap_read is still there. Originally, the testing and bisect were stable.
> Let me check what happens firstly.

Thanks! What's your fio_mmap_read job file and the readahead traces?

Thanks,
Fengguang