From: Shehjar Tikoo <shehjart@cse.unsw.edu.au>
Subject: ext4 pre-allocation performance  through nfsd
Date: Sat, 19 Jul 2008 10:37:16 +1000
Message-ID: <4881373C.10404@cse.unsw.edu.au>
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To: linux-ext4@vger.kernel.org
Sender: linux-ext4-owner@vger.kernel.org

Hi All

FYI, I ran some performance tests for a feature that incorporates 
pre-allocation support into linux nfsd. The patch is a 
proof-of-concept but the measurements are still relevant for this list.

1. Sequential read throughput with iozone reading a file written
using various pre-allocation sizes through nfsd:
http://www.gelato.unsw.edu.au/~shehjart/docs/nfsmeasurements/ext4fallocate_read.png

2. Sequential write throughput with iozone over NFS mount with the 
nfsd writing the file contents to disk using pre-allocation.
http://www.gelato.unsw.edu.au/~shehjart/docs/nfsmeasurements/ext4fallocate_write.png

Please see the following thread for more details.
http://thread.gmane.org/gmane.linux.nfs/21365

 From the write throughput plot, its clear that pre-allocation would be
highly beneficial if the pre-allocation overhead can be reduced.


Thanks
Shehjar