Re: and nicer too - Re: [PATCH] epoll more scalable than poll

From: Davide Libenzi (davidel@xmailserver.org)
Date: Fri Nov 01 2002 - 12:45:37 EST


On Fri, 1 Nov 2002, Dan Kegel wrote:

> Davide Libenzi wrote:
> >>Do you avoid the cost of epoll_ctl() per new fd?
> >
> > Jamie, the cost of epoll_ctl(2) is minimal/zero compared with the average
> > life of a connection.
>
> Depends on the workload. Where I work, the http client I'm writing
> has to perform extremely well even on 1 byte files with HTTP 1.0.
> Minimizing system calls is suprisingly important - even
> a gettimeofday hurts.

Dan, is it _one_ gettimeofday() or a gettimeofday() inside a loop ?
gettimeofday() is of the order of few microseconds ... and If your clients
works with anything alse than a loopback, few microseconds shouldn't weigh
in much compared to connect/send/recv/close on a network connection. It is
not much the fact that you transfer one byte, it's the whole TCP handshake
cost that weighs in.

- Davide

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