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From "Xavier Hanin" <xavier.ha...@gmail.com>
Subject Re: ivy:retrieve performance
Date Thu, 14 Jun 2007 17:09:12 GMT
Great, thanks a lot for these data!

Xavier

On 6/14/07, Buck, Robert <rbuck@verisign.com> wrote:
>
> What the performance test did is:
>
> 1. increase by powers of 2 a file size variable
>
> 2. for each file size, create/open a new file
>
> 3. write specified number of bytes to file
>
> 4. close file
>
> Tests were performed on two systems:
>
> 1. IBM ThinkPad T42 (slow) laptop, stock hardware, 1.5GB RAM
>
> 2. Dell Dual CPU, 5150, 64-bit Red Hat 4; (2) SAS 15k 146GB disks in
> RAID 1 configuration; 16 GB RAM; this is production grade hardware.
>
> Both sytems produced similar profiles (shape), however, on the
> production hardware with Linux (ext2, I believe) the numbers were
> substantially greater (makes sense when you consider the fast disks I
> have; at 3GB/sec rates, these SAS drives scream).
>
> In both cases buffers were configured for both Old IO and New IO. With
> NIO direct buffers were used. In both cases, I determined the ideal
> buffer sizes based upon experimentation to be around 32kb - 64 kb. Going
> to buffer sizes less than, or greater than, this range reduced overall
> throughput.
>
> -Bob
>
> > -----Original Message-----
> > From: Xavier Hanin [mailto:xavier.hanin@gmail.com]
> > Sent: Thursday, June 14, 2007 8:38 AM
> > To: ivy-user@incubator.apache.org
> > Subject: Re: ivy:retrieve performance
> >
> > On 6/14/07, Buck, Robert <rbuck@verisign.com> wrote:
> > >
> > > Folks,
> > >
> > > We benchmarked a number of JDK IO API's for an internal project. To
> > > neutralize any questions regarding NIO vs Old IO, please
> > take a look
> > > at the attached diagram. These rates will be largely
> > identical on both
> > > Linux and Windows. Blue line NIO, red line old io.
> >
> >
> > I've uploaded the image here:
> > http://www.flickr.com/photos/41363014@N00/548163404/
> >
> > Could you give a little bit more details about how you did
> > the tests: jvm used, size of buffer used for old IO, ...
> >
> > According to your tests it seems that NIO should be preferred
> > in any case, it wasn't what some users in the javalobby
> > thread seemed to say. So I wonder what makes the difference.
> >
> > Xavier
> >
> > If you do not get the attached JPEG file, let me know. I can send it
> > > directly to you if you so request.
> > >
> > > Cheers,
> > >
> > > Bob
> > >
> > > > -----Original Message-----
> > > > From: Xavier Hanin [mailto:xavier.hanin@gmail.com]
> > > > Sent: Thursday, June 14, 2007 6:22 AM
> > > > To: ivy-user@incubator.apache.org
> > > > Subject: Re: ivy:retrieve performance
> > > >
> > > > On 6/14/07, Gilles Scokart <gscokart@gmail.com> wrote:
> > > > >
> > > > > > 2. The buffer in FileUtils.java is too small. It's set at
> > > > 8192. It
> > > > > > seems to
> > > > > > > be much better for me to set it much larger. This is due
to
> > > > > > > the fact
> > > > > > that
> > > > > > > it
> > > > > > > needs to read and write simultaneously. The bigger the
> > > > buffer is,
> > > > > > > the smaller number of time, HD header has to move. For
> > > > me, 65536
> > > > > > > seems to perform much better but I haven't tried
> > other numbers.
> > > > > >
> > > > > >
> > > > > > I'd like to get more feedback on this. One use case is
> > > > not the other.
> > > > > This
> > > > > > size has been borrowed from Ant copy mechanism. Maybe
> > > > what we could
> > > > > > do
> > > > > is
> > > > > > make this configurable, so that one could adapt to its
> > > > needs. Or try
> > > > > > to guess a good size depending on the size (when it's
> > possible
> > > > > > to get an
> > > > > idea
> > > > > > of the size before copying).
> > > > > >
> > > > > > Xavier
> > > > > >
> > > > >
> > > > >
> > > > > Couldn't we use the nio for that?  (See
> > > > > http://www.javalobby.org/java/forums/t17036.html)
> > > >
> > > >
> > > > According to comments 10 and 11 NIO have bad performance
> > for large
> > > > files on linux, and input stream with byte buffer is
> > pretty close to
> > > > NIO for small files (see comment 13 conclusion). So I'm not sure
> > > > switching to NIO would indeed help a lot. According to
> > the tests in
> > > > the thread you pointed using a 64kB buffer seems to be a
> > good choice
> > > > (which confirms  testn tests), at least for large files. OTOH the
> > > > last conclusion (comment 17) is different.
> > > > So I don't really know what to think about that. We
> > should make some
> > > > tests on several platforms and jvms to draw conclusion
> > ourself, but
> > > > it takes time.
> > > >
> > > >
> > > > Xavier
> > > >
> > > > Gilles
> > > > >
> > > > >
> > > > >
> > > > >
> > > >
> > > >
> > > > --
> > > > Xavier Hanin - Independent Java Consultant Manage your
> > dependencies
> > > > with Ivy!
> > > > http://incubator.apache.org/ivy/
> > > >
> > >
> >
> >
> >
> > --
> > Xavier Hanin - Independent Java Consultant Manage your
> > dependencies with Ivy!
> > http://incubator.apache.org/ivy/
> >
>



-- 
Xavier Hanin - Independent Java Consultant
Manage your dependencies with Ivy!
http://incubator.apache.org/ivy/

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