Date: Fri, 1 Apr 2016 16:04:12 +1100
From: Dave Chinner <david@fromorbit.com>
To: Jens Axboe <axboe@fb.com>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-block@vger.kernel.org
Subject: Re: [PATCHSET v3][RFC] Make background writeback not suck
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On Thu, Mar 31, 2016 at 09:29:30PM -0600, Jens Axboe wrote:
> On 03/31/2016 06:56 PM, Dave Chinner wrote:
> >I'm not changing the host kernels - it's a production machine and so
> >it runs long uptime testing of stable kernels.  (e.g. catch slow
> >memory leaks, etc). So if you've disabled throttling in the guest, I
> >can't test the throttling changes.
> 
> Right, that'd definitely hide the problem for you. I'll see if I can
> get it in a reproducible state and take it from there.
> 
> On your host, you said it's SCSI backed, but what does the device look like?

HW RAID 0 w/ 1GB FBWC (dell h710, IIRC) of 2x200GB SATA SSDs
(actually 256GB, but 25% of each is left as spare, unused space).
Sustains about 35,000 random 4k write IOPS, up to 70k read IOPS.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com