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Gmane
From: Francois Tigeot <ftigeot <at> wolfpond.org>
Subject: VFS accounting performance benchmarks
Newsgroups: gmane.os.dragonfly-bsd.kernel
Date: Tuesday 20th December 2011 09:07:22 UTC (over 5 years ago)
Most of the VFS accounting work is now in the tree (and disabled by
default,
enable it with vfs.accounting_enabled="1" in /boot/loader.conf).
Only a potentially disruptive commit to enable it for / has not been
pushed.

Since VFS accounting uses a per mount-point spinlock to protect its
counters, 
there is some concern it will degrade write performance on SMP machines.

To measure if this was the case or not, I've run some blogbench benchmarks
on
a small Xeon system; the details of the test and the results are in the
attached PDF.

VFS accounting kernel was from 2011-12-19
Kernel without VFS accounting was from 2011-11-19

For my part I think the results are inconclusive: either there's no
measurable
performance difference or the choice of benchmark was bad.

-- 
Francois Tigeot
 
CD: 4ms