[Icecast] Re: cpu usage for ices and oggenc

[Andy Baxter]

On Thu, 14 Oct 2004 10:43:50 +1000, Michael Smith wrote:

> 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. 
> 
> Mike

It looks like this is the problem - the cpu times from
/proc/[pid]/stat are stuck at zero for ices, but not for some of the other
processes. Killing the process drops the total cpu use by about 13%, which
fits with the amount needed by oggenc.