[Libevent-users] performance patch

[William Ahern]

On Wed, Feb 27, 2008 at 02:54:41AM +0300, Vsevolod Stakhov wrote:
> Tani Hosokawa ?????:
<snip>
> >significant amount of processing to do per request.  The reason I put 
> >1024 in there is all implementations that I know of silently truncate 
> >the backlog parameter to the system's maximum.  The reason I don't use 
> >SOMAXCONN is some OS (older Solaris for sure) are incorrect for backward 
> >compatibility reasons, and other OS are incorrect because the actual 
> >setting is dynamically tunable via sysctl.
> >
<snip>
> 
> As POSIX requires SOMAXCONN to be defined in sys/socket.h it is safe to 
> use this value or define some constant in configure script, that detects 
>  SOMAXCONN definition. Also in old Solaris systems backlog was limited 
> to 5.

The problem with SOMAXCONN is the same as FOPEN_MAX (ISO C). The runtime
limit is not the same as the compile-time constant. In fact, usually the
runtime limit is much higher.

On all of my boxes FOPEN_MAX is defined to be 16 or 20. Yet that is
definitely not the runtime limit.