Alex, Yes, I'm developing an audio application that'd greatly benefit from 1ms or greater precision.
I'll look into both those options. Thanks, Paul S. -------- Original Message -------- On Dec 14, 2018, 20:02, Alexandre Ratchov wrote: > On Thu, Dec 13, 2018 at 09:27:12PM +0000, Paul Swanson wrote: >> Hi, >> >> I'm trying to understand how interval timers work in OpenBSD, >> but I'm a little stuck on this line from the getitimer / setitimer man page: >> >> "Time values smaller than the resolution of the system clock >> are rounded up to this resolution (typically 10 milliseconds)." >> >> Does this mean that 10 milliseconds is the shortest interval possible >> with a system interval timer? >> >> If so, are there other userland options for more precise timers? >> > > What would need a more precise timer? with what resolution? > > On amd64, you could build a kernel with HZ=1024, which gives a timer > that ticks every 1ms. I use this since ~2005 for MIDI programs. > > If the program that needs a precise timer involves audio, you could > also use the sound card clock instead. For instance by running sndiod > with "-z 120" option then call your code in the sio_onmove(3) > call-back. The advantage of this approach is that you get a unique > clock source, which avoids may problems.
