Re: [PATCH] fs-writeback: drop wb->list_lock during blk_finish_plug()

[Dave Chinner]

On Sun, Sep 13, 2015 at 09:12:44AM -0400, Chris Mason wrote:
> On Sat, Sep 12, 2015 at 07:46:32PM -0400, Chris Mason wrote:
> > I don't think the XFS numbers can be trusted too much since it was
> > basically bottlenecked behind that single pegged CPU.  It was bouncing
> > around and I couldn't quite track it down to a process name (or perf
> > profile).
> 
> I'll do more runs Monday, but I was able to grab a perf profile of the
> pegged XFS CPU.  It was just the writeback worker thread, and it
> hit btrfs differently because we defer more of this stuff to endio
> workers, effectively spreading it out over more CPUs.
> 
> With 4 mount points intead of 2, XFS goes from 140K files/sec to 250K.
> Here's one of the profiles, but it bounced around a lot so I wouldn't
> use this to actually tune anything:

mkfs.xfs -d agcount=64 ....

Cheers,

Dave.
-- 
Dave Chinner
david@xxxxxxxxxxxxx
--
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/