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From testn <te...@doramail.com>
Subject Re: ivy:retrieve performance
Date Thu, 21 Jun 2007 11:07:37 GMT

Hi Xavier,

Any plan to put it in alpha2? It doesn't look like it requires a lot of work
if we just want to change the buffer size. nio may be a long shot.

Thanks


Xavier Hanin wrote:
> 
> 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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