Re: [PATCH RFC] nilfs2: continuous snapshotting file system

[Szabolcs Szakacsits]

On Wed, 20 Aug 2008, Andrew Morton wrote:
> On Thu, 21 Aug 2008 00:25:55 +0300 (MET DST)
> Szabolcs Szakacsits <szaka@xxxxxxxxxxx> wrote:
> 
> > 
> > On Thu, 21 Aug 2008, Ryusuke Konishi wrote:
> > > >> Some impressive benchmark results on SSD are shown in [3],
> > > >
> > > >heh.  It wipes the floor with everything, including btrfs.
> > 
> > It seems the benchmark was done over half year ago. It's questionable how 
> > relevant today the performance comparison is with actively developed file 
> > systems ...
> > 
> > > >But a log-based fs will do that, initially.  What will the performace
> > > >look like after a month or two's usage?
> > > 
> > > I'm using NILFS2 for my home directory for serveral months, but so far
> > > I don't feel notable performance degradation. 
> > 
> > I ran compilebench on kernel 2.6.26 with freshly formatted volumes. 
> > The behavior of NILFS2 was interesting.
> > 
> > Its peformance rapidly degrades to the lowest ever measured level 
> > (< 1 MB/s) but after a while it recovers and gives consistent numbers.
> > However it's still very far from the current unstable btrfs performance. 
> > The results are reproducible.
> > 
> >                     MB/s    Runtime (s)
> >                    -----    -----------
> >   btrfs unstable   17.09        572
> >   ext3             13.24        877
> >   btrfs 0.16       12.33        793
> >   nilfs2 2nd+ runs 11.29        674
> >   ntfs-3g           8.55        865
> >   reiserfs          8.38        966
> >   nilfs2 1st run    4.95       3800
> >   xfs               1.88       3901
> 
> err, what the heck happened to xfs?  Is this usual?

vmstat typically shows that xfs does ... "nothing". It uses no CPU time and 
doesn't wait for I/O either. 

	Szaka

--
NTFS-3G:  http://ntfs-3g.org

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