OT epoll wang fight [was: LDAP timeouts during failure conditions]

Phil Mayers p.mayers at imperial.ac.uk
Fri Jul 1 12:03:01 CEST 2011


On 30/06/11 20:28, Alexander Clouter wrote:
> Phil Mayers<p.mayers at imperial.ac.uk>  wrote:
>>
>> There's absolutely no discernible issue with using epoll over select
>> in any app
>>
> ...so you will be showing me example epoll() code for Windows, Solaris
> and *BSD eh? ;)

Sure:

http://monkey.org/~provos/libevent/

Why invent when you can steal? Or even "use"?

>
>> except a micro-benchmark designed to test syscall latency in the case
>> with small numbers of FDs.
>>
> I never mentioned benchmarks :P
>
> I was more muttering on the portability front, the path of #ifdef
> madness is a wicked one...udpfromto.c anyone (free beer to the person
> who finds the worst example of addition to #ifdef)?

Well, I did prefix my remarks with "if":

"""I do wonder if we might start running into problems with ..."""

So the whole following sentence was predicated on the assumption that 
problems would arise; if they did "#ifdef is hard let's go shopping" is 
hardly a suitable response.

Maybe it will never come up; maybe the usage patterns will mean select 
is fine for the foreseeable future. But:

  * If Josh and his ABFAB lot get their way, copies of FreeRADIUS will 
be serving as super-Shibboleth authenticators for all your users 
distributed web auth needs; 1000 open FDs seems like a pretty 
conservative number in that event, and;

  * If a windows native port is to work, there will probably need to be 
#ifdef code around a different event loop core for win32 anyway, since 
select is rubbish on that platform (63 FDs, IIRC?)

Anyway, offtopic as you say. My last post on the subject.



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