FreeBSD 5.3 I/O Performance / Linux 2.6.10 | Continued Discussion

Nick Pavlica linicks at
Wed Jan 26 10:47:05 PST 2005

  With the recent release of 4.11 I thought that I would give it a
spin and com pair my results with my previous testing.  I was blown
away by the performance difference between 4.11 and 5.3.  Iostat
showed a difference of over 30Mb/s difference between the two.  In
fact, it kept up or out performed fedora Core 3 with XFS in my
testing.  This seems to indicate that the 5.x branch may still needs
allot of performance work.  One of the interesting observations was
that 4.11 utilized much more of the processor than 5.3.  I hope that
the changes in 5.4 will help close this gap considerably.  Is there
any specific components of the 5.3 that have been identified to cause
this performance difference?

Your feedback/thoughts on this are appreciated!

On Mon, 24 Jan 2005 14:59:55 -0700, Nick Pavlica <linicks at> wrote:
> All,
>   I would like to start addressing some of the feedback that I have
> been given.  I started this discussion because I felt that it was
> important to share the information I discovered in my testing.  I also
> want to reiterate my earlier statement that this is not an X vs. X
> discussion, but an attempt to better understand the results, and
> hopefully look at ways of improving the results I had with FreeBSD
> 5.x.  I'm also looking forward to seeing the improvements to the 5.x
> branch as it matures.  I want to make it very clear that this is NOT A
> "Religious/Engineering War", please don't try to turn it into one.
> That said, lets move on to something more productive.  I installed
> both operating systems using as many default options as possible and
> updated them with all of the latest patches.  I was logged in via SSH
> from my workstation while running the tests.  I didn't have X, running
> on any of the installations because it wasn't need.  CPU and RAM
> utilization wasn't an issue during any of the tests, but the disk I/O
> performance was dramatically different.  Please keep in mind that I
> ran these tests over and over to see if I had consistent results.  I
> even did the same tests on other pieces of equipment not listed in my
> notes that yielded the same results time and time again.  Some have
> confirmed that they have had similar results in there testing using
> other testing tools and methods.  This makes me wounder why the gap is
> so large, and how it can be improved?
> I think that it would be beneficial to have others in this group do
> similar testing and post there results.  This may help those that are
> working on the OS itself to find trouble areas, and ways to improve
> them.  It may also help clarify many of the response questions because
> you will be able to completely control the testing environment.  I
> look forward to seeing the testing results, and any good feedback that
> helps identify specific tuning options, or bugs that need to be
> addressed.
> Thanks!
> --Nick Pavlica
> --Laramie, WY

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