R: [Asterisk-Users] Hyperthreading?

[Manuel Wenger]

That's the problem we had with Asterisk and HT on a 2.4 Kernel: whenever Asterisk was staying in the RTP stream, and HT was enabled (on a Dell Dual Xeon system), we had choppy audio. After disabling HT, everything was fine again. Nothing measurable, indeed, but you could definitely hear it. So there *must* be something.

-Manuel

-----Messaggio originale-----
Da: Peter Corlett [mailto:abuse at cabal.org.uk] 
Inviato: martedì, 1. giugno 2004 16:09
A: asterisk-users at lists.digium.com
Oggetto: Re: [Asterisk-Users] Hyperthreading?


Andrew Kohlsmith <akohlsmith-asterisk at benshaw.com> wrote:
[...]
> They can't? HT is detected in /proc/cpuinfo (flags) and I see two 
> processors with 2.4.25 SMP kernels... What exactly isn't it using?

Linux doesn't realise that scheduling a process onto one virtual CPU reduces the performance available on the other. There can be some quite bizarre scheduling decisions made as a result that can slow things down. On the other hand, for some tasks, it might not cause problems and thus you'll get a boost.

As ever, the answer is to benchmark your configuration with and without HT to see. There's no simple answer.


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