[ofa-general] Re: [PATCH 2/3][NET_BATCH] net core use batching

[David Miller]

From: Andi Kleen <andi at firstfloor.org>
Date: Wed, 10 Oct 2007 12:23:31 +0200

> On Wed, Oct 10, 2007 at 02:25:50AM -0700, David Miller wrote:
> > The chip I was working with at the time (UltraSPARC-IIi) compressed
> > all the linear stores into 64-byte full cacheline transactions via
> > the store buffer.
> 
> That's a pretty old CPU. Conclusions on more modern ones might be different.

Cache matters, just scale the numbers.

> I suppose it would be an interesting experiment at least.

Absolutely.

I've always gotten very poor results when increasing the TX queue a
lot, for example with NIU the point of diminishing returns seems to
be in the range of 256-512 TX descriptor entries and this was with
1.6Ghz cpus.