[LAD] cpu spikes

[Jonathan E. Brickman]

On 01/24/2016 08:03 AM, Fokke de Jong wrote:
> Hi all,
>
> This is my first post here. I’m note new to audio programming or 
> linux, but I haven’t done much in terms of combining the two. Most of 
> my audio programming has been on os x.
>
> Currently working on some realtime convolution with lots of channels 
> and low latency requirements, but I am running into some unexpected 
> cpu-spikes and hope some of you might have an idea of possible causes.
>
> 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.
>
> [...snip...]
>
> 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.
>
> I remember reading somewhere that realtime threads cannot run more 
> than .95s every second. That would be very bad if it actually meant my 
> threads are blocked  run for a period of 50ms straight…
>
> Anyone have any thoughts on possible causes?
>
> best,
> Fokke
You're running Mint :-)  Lots of background bells and whistles there, 
lots of things which will crop up and interfere, things you cannot 
disable or turn off with absolute certainty.  If you want smooth power, 
you'll have to choose more carefully.  My current SOP in more detail here:

http://lsn.ponderworthy.com/doku.php/choosing_a_linux_platform_for_live_synth



-- 
Jonathan E. Brickman   jeb at ponderworthy.com   (785)233-9977
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