Re: [LAU] System Configuration: kernel, CPU frequency, hardware timers

On Mon, 27 Aug 2018, Kevin Cosgrove wrote: Some things have changed with cpufreq. - in days of old there was /etc/rc.d/*ondemand that ran 60 seconds after startup. This means no matter what you set for cpufreq it gets down graded 60 sec later. disable ondemand if your os comes with it. - Now days there is kernel modules that need to be loaded and effective before changing cpufreq stuff, otherwise it doesn't work... and ondemand has been moved to systemd to ensure this. So it is best if your os uses systemd to move you cpufreq setting script to systemd to replace ondemand. BTW this ondemand also waits 60 seconds. - newer intel cpus have a thing called "Boost" that can change your cpus frequency up and down above what performance sets it to. There are three choices here: Turn boost off in bios. Turn it off at run time. Set performances minimum and max speed to compensate... maybe higher than performance would. (yes I have more xruns at low latencies with Boost on) Setting performance is not about making sure your cpu runs as fast as possible. It is about making sure the cpu speed does not change, It seems at speed down changes I get xruns. However, I have set cpu governor to USER and set it hard to 800Mhz (lowest possible) and still very good xrun performance (like none in 8 hours running) while ondemand still gives xruns. So choose your speed and monitor cpu temperature and run it at the speed that gives you the highest temperature you are comfortable with. IMO you should be monitoring temperature anyway to catch dust build up or fan failure. -- Len Ovens www.ovenwerks.net