On Fri, Nov 26, 2004 at 03:14:30PM -0800, Jeremy Allison wrote:
> On Thu, Nov 25, 2004 at 09:46:11AM +0100, Volker Lendecke wrote:
> >
> > How much does sendfile gain us at all?

>
> 10%. I'm loath to give that up for some buggy network cards.
> It's off by default, the only purpose for that fix is to
> stop it breaking if on on a system that doesn't implement it.


Sendfile can give you a lot more on systems with relatively slower CPUs.
On a 4P Origin, using a sendfile-like call takes us from from being
CPU-bound in bcopy to doing line rate over 4 NICs. It is a very big win
for large streaming reads, which is a relatively common workload.

--
James Peach | jpeach@sgi.com | SGI Australian Software Group
I don't speak for SGI.