[openib-general] Re: Re: [PATCH] (fixed) reduce qp locking on cq poll

[Grant Grundler]

On Wed, Jan 26, 2005 at 09:37:49PM +0200, Michael S. Tsirkin wrote:
> Quoting r. Grant Grundler <iod00d at hp.com>:
> > Subject: Re: Re: [PATCH] (fixed) reduce qp locking on cq poll
> > 
> > On Wed, Jan 26, 2005 at 07:19:02PM +0200, Michael S. Tsirkin wrote:
> > > > I'm a little worried that you see no improvement from this patch -- it
> > > > doesn't seem like fast hardware should be required.
> > 
> > I was wondering the same thing. Why is fast HW required?
> 
> See below.

Sorry - I didn't see the answer "below".
Can you be more specific?

> > Can you quantify what you mean by "wild variations" and "big wins"?
> 
> Goes up or down up to 3% on a bad day. Anything less is noise for me.

Ok - I expect repeatability to be < 1% and ideally < 0.1%.
On a private LAN at least. :^)

> > Have you tried pinning the test processes to a particular CPU
> > with taskset?
> 
> No. Why will this help?

cacheline ping-ponging will be the same between test runs.

Did you see the difference in IPoIB numbers that I posted
earlier where I pegged the test processes to the same CPU
taking interrupts or a different CPU? 

For netperf, this was especially important for the system
running "netserver" process.

grant