From: Andrew Morton <akpm@linux-foundation.org>
To: Wu Fengguang <fengguang.wu@intel.com>
Cc: <linux-fsdevel@vger.kernel.org>, Jan Kara <jack@suse.cz>,
Dave Chinner <david@fromorbit.com>,
Christoph Hellwig <hch@infradead.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/3] bdi write bandwidth estimation
Date: Mon, 13 Jun 2011 15:23:30 -0700 [thread overview]
Message-ID: <20110613152330.056e2eba.akpm@linux-foundation.org> (raw)
In-Reply-To: <20110612151821.601514494@intel.com>
On Sun, 12 Jun 2011 23:18:21 +0800
Wu Fengguang <fengguang.wu@intel.com> wrote:
> Do bdi write bandwidth estimation in the flusher thread at 200ms intervals,
stdrant: anything which is paced using "seconds" is basically always
wrong. The bandwidth of storage systems varies by who-knows-how-many
orders of magnitude. If 200ms is correct for one system then it is
vastly incorrect for another.
A more suitable clock for this estimate would be "per 200 requests",
for a block-based BDI.
Also of course the bandwidth of a particular BDI varies vastly
depending on workload. For the purpose of this work, that's probably
a desirable thing.
next prev parent reply other threads:[~2011-06-13 22:23 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-12 15:18 [PATCH 0/3] bdi write bandwidth estimation Wu Fengguang
2011-06-12 15:18 ` [PATCH 1/3] writeback: account per-bdi accumulated written pages Wu Fengguang
2011-06-12 15:18 ` [PATCH 2/3] writeback: bdi write bandwidth estimation Wu Fengguang
2011-06-12 15:18 ` [PATCH 3/3] writeback: show bdi write bandwidth in debugfs Wu Fengguang
2011-06-13 22:23 ` Andrew Morton [this message]
2011-06-14 3:45 ` [PATCH 0/3] bdi write bandwidth estimation Wu Fengguang
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