Re: proposal about glib

[Magnus Bergman <magnusbe algonet se>]

On Mon, 30 Jun 2008 09:50:07 +1000
Erik de Castro Lopo <mle+gtk mega-nerd com> wrote:

> 
> yangyang hexun com wrote:
> 
> > 1）I use glib's main event loop, but why glib's main event loop
> > don't support epoll/kqueue?
> > 
> > The poll/select func's efficiency is very poor.
> 
> <lurk mode="off">
> 
> Do you have any pointers to studies that measure the relative
> performance? The only one I can find is this one (admittedly
> a little old):
> 
>     http://www.gelato.org/pdf/Illinois/gelato_IL2004_epoll_brecht.pdf
> 
> which shows select slightly ahead when there are less than 10000
> file descriptors.
> 
> </lurk>

There are some benchmarks on the libevent page
(http://monkey.org/~provos/libevent/). It is true that there isn't much
of a difference (epoll slightly worse and kqueue slightly better) with
a low number of file descriptors. In this benchmark the big difference
becomes tangible at about a thousand descriptors. The reason for the
difference in the benchmarks is the distribution of the load.
select/poll is especially bad if only a few file descriptors are active.