2008-07-19 00:51:50

by Shehjar Tikoo

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Subject: ext4 pre-allocation performance through nfsd

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