Date: Tue, 27 Oct 2009 08:50:39 +0800
From: Shaohua Li <shaohua.li@intel.com>
To: Jens Axboe <jens.axboe@oracle.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [RFC]cfq-iosched: improve hw_tag detection
Message-ID: <20091027005039.GA14819@sli10-desk.sh.intel.com>
References: <20091026091624.GA1169@sli10-desk.sh.intel.com> <20091026113555.GB10727@kernel.dk>
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On Mon, Oct 26, 2009 at 07:35:55PM +0800, Jens Axboe wrote:
> On Mon, Oct 26 2009, Shaohua Li wrote:
> > If active queue hasn't enough requests and idle window opens, cfq will not
> > dispatch sufficient requests to hardware. In such situation, current code
> > will zero hw_tag. But this is because cfq doesn't dispatch enough requests
> > instead of hardware queue doesn't work. Don't zero hw_tag in such case.
> 
> Thanks, that looks like a good fix. Curious, is this fixing some
> regression at your end?
No, just observed such issue when I play with cfq.

Thanks,
Shaohua
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