On Wed, 27 Jan 2021 10:02:48 -0800 (PST) Len Ovens <len@xxxxxxxxxxxxx> wrote: >On Wed, 27 Jan 2021, Michael Jarosch wrote: > >> As soon as frequency switching was introduced we LAU were told, not to >> use it to save xruns. And as far as I can tell, the rule still valid. Is >> there a chance in the future that we can stop thinking about it, because >> it just won't matter? Are we forced blowing loads of energy or do we >> spent too much time in sluggish UEFI menus? > >It depends. Setting jack to frame size 64 or lower has in my experience >shown xruns with frequency switching. This includes Intel's "Boost" >setting which is not turned off by setting performance. There seems to be >no problem when the speed goes up but I often see an xrun when the speed >goes down (just at speed change). > >However, Intel has been doing speed switching in the CPU for a while now >and we are still able to set a steady speed with that on the fly. So with >the AMD it may be similar. It may still be possible to set an upper and >lower speed limit. What they do not say, is that the advertized speed may >not be usable in steady state. With the Intel, the advertized speed can be >set for all cores and run that way at 100% core use and run forever >without over heating. AMD tends to advertize a cpu speed based on some >cores running slower and the cpu managing heat by slowing some cores down. >In this case one will have to experiment to find out what speed can be >safely run on all cores without over heating and use that speed for audio. >Hopefully this can be set on the fly. > >Another comment of "blowing loads of energy" with performance mode. It was >actually found that the old "ondemand" governor actually used more power >than "performance" in many cases. Ondemand has to wake up every once in a >while to see what is happening, but in performance mode the core can go to >an idle state. The newer intel powersave mode does not have this problem >but AMD (although they started work on their own governor for linux) can >only use ondemand. > >The easiest way to see power use is to watch core temperature... all power >used ends up as heat. > FWIW I'm running an earlier Ryzen5 here at 32 frames, mostly with Rosegarden and Yoshimi, using quite complex patches, and averaging 8 active channels at once. I don't see any Xruns. I do see the occasional one if I do things like load a full patch set over a running program. -- Will J Godfrey http://www.musically.me.uk http://yoshimi.github.io Say you have a poem and I have a tune. Exchange them and we can both have a poem, a tune, and a song. _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx https://lists.linuxaudio.org/listinfo/linux-audio-user
