performance of cache-intensive applications

performance of cache-intensive applications

[Igor Schein]

Hi,

I am using an open-source application on ix86 to perform a task which
is cache-intensive.  When I run consecutive iterations of the task on
a fixed input, the variance in timing of each iteration is extemely
high.   Needless to say, the test machine is always non-occupied.

On every other OS I tried, Solaris, HPUX, FreeBSD and Tru64, the
timing is very consistent between the iterations.  My question is, are
there known issues with L2 cache reuse in Linux kernel?

I can provide any necessary information for anyone interested in
addressing this issue, but I purposely skipped most technical details
in this post to keep it simple.

Thanks in advance.

Igor

RE: performance of cache-intensive applications

[Nakajima, Jun]

This kind of problem could be solved by cache coloring. There should be some
patch available for Linux. I don't know if the other OSes you tried
implement cache coloring, though.

Jun

> -----Original Message-----
> From: Igor Schein [mailto:igor@txc.com]
> Sent: Tuesday, December 03, 2002 6:09 PM
> To: linux-kernel@vger.kernel.org
> Subject: performance of cache-intensive applications
> 
> Hi,
> 
> I am using an open-source application on ix86 to perform a task which
> is cache-intensive.  When I run consecutive iterations of the task on
> a fixed input, the variance in timing of each iteration is extemely
> high.   Needless to say, the test machine is always non-occupied.
> 
> On every other OS I tried, Solaris, HPUX, FreeBSD and Tru64, the
> timing is very consistent between the iterations.  My question is, are
> there known issues with L2 cache reuse in Linux kernel?
> 
> I can provide any necessary information for anyone interested in
> addressing this issue, but I purposely skipped most technical details
> in this post to keep it simple.
> 
> Thanks in advance.
> 
> Igor
> 
> -
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RE: performance of cache-intensive applications

[Giuliano Pochini]

On 04-Dec-2002 Igor Schein wrote:
> Hi,
> 
> I am using an open-source application on ix86 to perform a task which
> is cache-intensive.  When I run consecutive iterations of the task on
> a fixed input, the variance in timing of each iteration is extemely
> high.   Needless to say, the test machine is always non-occupied.

CPU bound or I/O bound ?  What kernel version ?  IDE or
SCSI ?  vmstat ?  Other details ?


Bye.