Re: [Lse-tech] zerocopy pipe, new version

[Hubertus Franke <frankeh@watson.ibm.com>]

On Tue, Jan 15, 2002 at 03:20:38PM -0500, Benjamin LaHaise wrote:
> On Tue, Jan 15, 2002 at 09:08:45PM +0100, Manfred Spraul wrote:
> > My patch is definitively WIP - right now I again broke the -ENOMEM and
> > -EFAULT handling.
> 
> I am aware of that, but the lse-tech posting made it sound as if things are 
> great now since the SMP numbers improved.  Please folks, remember that UP 
> numbers are important too.
> 
> 		-ben
> -- 
> Fish.

Ben, yes you are right, the lse-posting in a second reading is misleading.
As reported previously http://lse.sourceforge.net/pipe/pipe-report
UP numbers see degradations for LM-Bench, other benchmarks are OK.

This is not solved either by an integration of zero-copy with large pipes.
We have however shown that the for SMP systems adding larger pipes to
zero-copy pipes makes sense and for UP and 1-way sticking with a 1-page 
pipe does not degradate Manfred's patch.

It hence boils down to a proper parameterization of the pipe dependent on 
the configuration.

-- Hubertus