[Asterisk-Users] Has anyone had problems with Digium TDM400P and hyperthreading?

[Paul Hewlett]

On Friday 15 April 2005 07:45, Damian Funnell wrote:
> Digium have told us that a problem that we are having (with accuracy of
> zap interface as measured using zttest) may be due to the fact that we
> have a Xeon processor with hyperthreading and have suggested turning H/T
> off.
>
> Anyone else experienced a problem like this?  No too keen about turning
> H/T off, as we're running the SMP RH kernel and don't really feel like
> replacing the kernel (and other kernel-specific bits) on the off chance
> that H/T is actually the problem.

AFAIK, HT is not useful if your application does a lot of floating point 
calculations as there is only one FPU. What happens is that there is a 1-2% 
overhead when HT is on (for semaphores and such). IF HT does not gain more 
than this 1-2% you actually end up slowing things down and this is the case 
for floating point applications (because of only one FPU).

IS asterisk floating point heavy ?

Paul H
 

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Paul Hewlett (Linux #359543) 
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