From mboxrd@z Thu Jan 1 00:00:00 1970 From: Trond Myklebust Subject: Re: [RFC] nfs: use 4*rsize readahead size Date: Tue, 02 Mar 2010 09:19:23 -0500 Message-ID: <1267539563.3099.43.camel@localhost.localdomain> References: <20100224024100.GA17048@localhost> <20100224032934.GF16175@discord.disaster> <20100224041822.GB27459@localhost> <20100224052215.GH16175@discord.disaster> <20100224061247.GA8421@localhost> <20100224073940.GJ16175@discord.disaster> <20100226074916.GA8545@localhost> <20100302031021.GA14267@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Cc: Dave Chinner , "linux-nfs@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , Linux Memory Management List , LKML To: Wu Fengguang Return-path: In-Reply-To: <20100302031021.GA14267@localhost> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org On Tue, 2010-03-02 at 11:10 +0800, Wu Fengguang wrote:=20 > Dave, >=20 > Here is one more test on a big ext4 disk file: >=20 > 16k 39.7 MB/s > 32k 54.3 MB/s > 64k 63.6 MB/s > 128k 72.6 MB/s > 256k 71.7 MB/s > rsize =3D=3D> 512k 71.7 MB/s > 1024k 72.2 MB/s > 2048k 71.0 MB/s > 4096k 73.0 MB/s > 8192k 74.3 MB/s > 16384k 74.5 MB/s >=20 > It shows that >=3D128k client side readahead is enough for single disk > case :) As for RAID configurations, I guess big server side readahead > should be enough. There are lots of people who would like to use NFS on their company WAN, where you typically have high bandwidths (up to 10GigE), but often a high latency too (due to geographical dispersion). My ping latency from here to a typical server in NetApp's Bangalore office is ~ 312ms. I read your test results with 10ms delays, but have you tested with higher than that? Cheers Trond -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org