From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@infradead.org>
Subject: Re: Performance degradation in IO writes vs. reads (was scsi-mq V2)
Date: Thu, 21 Aug 2014 06:03:15 -0700
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Cc: Christoph Hellwig <hch@infradead.org>,
	James Bottomley <James.Bottomley@HansenPartnership.com>,
	Jens Axboe <axboe@kernel.dk>,
	Bart Van Assche <bvanassche@fusionio.com>,
	Robert Elliott <Elliott@hp.com>, linux-scsi@vger.kernel.org,
	linux-kernel@vger.kernel.org, viro@ZenIV.linux.org.uk,
	Or Gerlitz <ogerlitz@mellanox.com>,
	Oren Duer <oren@mellanox.com>,
	"Nicholas A. Bellinger" <nab@linux-iscsi.org>,
	Mike Christie <michaelc@cs.wisc.edu>,
	linux-fsdevel@vger.kernel.org, Max Gurtovoy <maxg@mellanox.com>
To: Sagi Grimberg <sagig@dev.mellanox.co.il>
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On Thu, Aug 21, 2014 at 03:32:09PM +0300, Sagi Grimberg wrote:
> So I just got back to checking this issue of *extremely low* IO write
> performance I got in 3.16-rc2.

Please test with 3.16 final.  There once issue each in aio and dio
that caused bad I/O performance regression that were only fixed last
minute in the 3.16 cycle.