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From: Jim Rees <rees@umich.edu>
To: Vivek Trivedi <vtrivedi018@gmail.com>
Cc: "Myklebust, Trond" <Trond.Myklebust@netapp.com>,
	linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org,
	Namjae Jeon <linkinjeon@gmail.com>,
	amit.sahrawat83@gmail.com
Subject: Re: NFS: low read/stat performance on small files
Date: Fri, 23 Mar 2012 07:49:13 -0400	[thread overview]
Message-ID: <20120323114913.GB24489@umich.edu> (raw)
In-Reply-To: <CAKX=r8A90b25VKXC1qtAota9DqDrj37xFT511DuvrZ=1Eux6Xw@mail.gmail.com>

Vivek Trivedi wrote:

  204800 bytes (200.0KB) copied, 0.027074 seconds, 7.2MB/s
  Read speed for 200KB file is 7.2 MB

  104857600 bytes (100.0MB) copied, 9.351221 seconds, 10.7MB/s
  Read speed for 100MB file is 10.7 MB
  
  As you see read speed for 200KB file is only 7.2MB/sec while it is
  10.7 MB/sec when we read 100MB file.
  Why there is so much difference in read performance ?
  Is there any way to achieve high read speed for small files ?

That seems excellent to me.  204800 bytes at 11213252 per sec would be 18.2
msec, so your per-file overhead is around 9 msec.  The disk latency alone
would normally be more than that.

  reply	other threads:[~2012-03-23 12:15 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-23 11:17 Vivek Trivedi
2012-03-23 11:49 ` Jim Rees [this message]
2012-03-23 12:16   ` Myklebust, Trond
2012-03-24  7:02     ` Namjae Jeon

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