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Date: Fri, 26 Aug 2011 20:20:57 +0800
From: Wu Fengguang <fengguang.wu@intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Vivek Goyal <vgoyal@redhat.com>,
        "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
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        Andrea Righi <arighi@develer.com>, linux-mm <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/5] writeback: dirty position control
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On Fri, Aug 26, 2011 at 08:11:50PM +0800, Peter Zijlstra wrote:
> On Fri, 2011-08-26 at 19:26 +0800, Wu Fengguang wrote:
> > Now I get 3 figures. Test case is: run 1 dd write task for 300s, with
> > a "disturber" dd read task during roughly 120-130s. 
> 
> Ah, but ideally the disturber task should run in bursts of 100ms
> (<feedback period), otherwise your N is indeed mostly constant.

Ah yeah, the disturber task should be a dd writer! Then we get

- 120s: N=1 => N=2
- 130s: N=2 => N=1

I'll try it right away.

Thanks,
Fengguang