Messages in this thread | | | Date | Wed, 20 Nov 2002 22:04:26 +0000 | From | Jamie Lokier <> | Subject | Re: [rfc] epoll interface change and glibc bits ... |
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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?
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