[Asterisk-Users] Child PID's

[Tim Panton]

On 4 Mar 2006, at 08:30, Paul Hewlett wrote:

> On Thursday 02 March 2006 22:19, Matt Schulte wrote:
>> All, I'm not sure how to word this question but we're noticing a  
>> lot of
>> our asterisk boxes no longer have multiple asterisk child processes.
>> i.e. doing a 'ps ax' reveals only 1 asterisk PID when normally I'm  
>> used
>> to seeing 8+ .. There is no rhyme or reason to it, and we're using  
>> the
>> safe_asterisk script which has always worked in the past. Ast  
>> 1.2.4, zap
>> 1.2.4, naturally..
>>
>> All my research has revealed nothing, regarding this, any  
>> suggestions?
>> What I'm worried about, of course, is the single process getting
>> overloaded with CPU calls and potentially denying service.
>>
>> 	Matt @ NetLogic
>
> Matt
>
>    On 2.4 kernels you would be using the LinuxThreads  
> implementation of POSIX
> threads. This emulated the POSIX threading model with some  
> limitations -
> signals could only be delivered to the master thread - there was a  
> 'hidden'
> control thread etc... Context switching performance in LinuxThreads  
> was known
> to be poor (sometimes measured in whole seconds) IBM and RedHat  
> worked on
> solving this problem - IBM's effort (NGPT) was abandoned in favour of
> REdHat's (NPTL). NPTL was introduced in RedHat 9 (as I remember).  
> Most modern
> distro's now use NPTL and one can tell this by doing 'ps ax' and  
> seeing only
> one asterisk task instead of many. Asterisk without NPTL is  
> probably not good
> for high thruput sites.
>
>   And Gentoo users beware - only 2006.0 has adopted NPTL as default.
> Previously one had to rebuild the toolchain by specifying USE flags  
> "nptl
> nptlonly" to get NPTL threads (and this takes a long time...)
>
>   Have u upgraded to a more modern distro recently ?
>

Also take a look at the value of LD_ASSUME_KERNEL in your shell  
startup scripts
and profiles.
I had a similar weirdness caused by a line in my personal .profile
LD_ASSUME_KERNEL=2.4.1
which I'd put in ages ago to test some (non asterisk) software and  
never taken out.


tim at mexuar.com