[LAD] cpu spikes

Len Ovens len at ovenwerks.net
Sun Jan 24 15:13:44 UTC 2016

On Sun, 24 Jan 2016, Fokke de Jong wrote:

> I’m processing 32 sample-blocks at 48KHz but roughly every 0,6 seconds I get a
> large spike in cpu usage. This cannot possibly be explained by my algorithm,
> because the load should be pretty stable. 

> I’m running (more or less default install, no additional services run-in) Linux
> Mint 17.3 with a 3.19.0-42-lowlatency kernel on a core i7-6700 with
> hyperthreading/turbo disabled.

> Anyone have any thoughts on possible causes?

Bad kernel driver? WIFI drivers are known bad for things like this. An 
interupt driver can block if it is designed badly. I found on one machine 
I had to unload the the kernel module for my wifi as it actually created 
more problems when I turned the power off to the tx than when it was on. 
(it seems to me on my wifi, when it was turned on I got xruns every 5 
seconds, but with it turned off it was every half second or so... sounds 
very close to 0.6, unloading the kernel module fixed it)

Cron should also be turned off, but that is probably not the problem here. 
Cron runs super "nice" but there seem to be some things it does like 
packge update that can cause problems too. I turn off cron while 

Len Ovens

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