Re: [rfc] epoll interface change and glibc bits ...

From: Davide Libenzi (davidel@xmailserver.org)
Date: Wed Nov 20 2002 - 17:08:43 EST


On Wed, 20 Nov 2002, Jamie Lokier wrote:

> Davide Libenzi wrote:
> > And the lower size of the structure will help to reduce the amount of
> > memory transfered to userspace. I just saw that adding the extra "obj"
> > member lowered performance of about 15% with crazy tests like Ben's
> > pipetest. This because it creates, on my machine, more than 400000 events
> > per second, and saving memory bandwidth on such conditions is a must. With
> > the "more human" http test performance are about the same.
>
> I'd be quite surprised if 400,000 word/sec of memory bandwidth can
> explain a 15% time difference, especially considering all the other
> things that are done to communicate over a pipe (wakeups etc).

Jamie, they were 16 bytes * 400000, and the token passed through the pipe
was 12 bytes.

- Davide

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