[Icecast] cpu usage for ices and oggenc

Michael Smith msmith at xiph.org
Thu Oct 14 00:43:50 UTC 2004

On Thursday 14 October 2004 03:11, Andy Baxter wrote:
> I'm running ices-kh to stream from jack at 64kbps, and also using oggenc
> (with ecasound via jack) to record the audio to disk at the same time.
> This is also running at 64kbps.
> ices is using virtually no cpu (0.0%), but oggenc is using 15-16%. I can't
> see why there should be such a difference - both are recording the same
> audio stream in real time at the same bitrate. oggenc is getting its input
> as a raw audio pipe from ecasound. I checked with ldd, and both are using
> the same version of libvorbisenc.
> Why is this happening?

Whilst I don't have a definite answer, it's very common for certain types of 
application to cause 'top' (and any tool that works in a similar way) to 
drastically under-report cpu usage. 

A common example familiar to many (it's probably less noticable now, since 
cpus are much faster) is xmms playing mp3s - on a system where that was known 
to take ~10-15% of cpu time, top consistently reported 0% used. 

So it might just be that the cpu usage is being mis-reported. 


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