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SubjectRe: [rfc] epoll interface change and glibc bits ...
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).

Btw, I have seen variations of that magnitude in other network tests
that I've done that _appear_ to be explained by small changes to the
code like that, but the next day or week the variation stops
correlating with the change. Page colouring affecting benchmarks
again?

-- Jamie
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