On Thu, 2004-05-27 at 22:58, Arjan van de Ven wrote: > On Fri, 2004-05-28 at 02:39, Fernando Pablo Lopez-Lezcano wrote: > > On Thu, 2004-05-27 at 17:25, Fernando Pablo Lopez-Lezcano wrote: > > > Hi all. I'm trying to track the cause of high scheduling latency peaks > > > in FC2 that make the system unusable for low latency audio work. > > > > > > Test systems: PIV laptop, radeon video chipset, AMD64 desktop, radeon > > > video chipset. How I test: I run the Jack (Jack Audio Connection Kit) > > > sound server with 2 or 3 128 frame buffers for low latency operation > > > through the Qjackctl gui front-end. I then start GUI apps that use Jack > > > (for example Freqtweak, Hydrogen and Jamin). I see plenty of buffer > > > xruns of varying durations during the app load process and afterwards. > > > > More data I forgot to include: > > Jack is running with SCHED_FIFO priority. For achieving that I run a > > custom kernel (currently based on Arjan's 1.391) with preempt enabled > > and the realcap kernel module (by Jack O'Quin) added. > > can you disable preempt? That should improve latencies.... I'll try that and report back. A while back - probably 2.6.4-1.279 or whereabouts - I did a comparison (because of reports that it should be better that preempt be off) and latencytest reported better latencies with preempt on. Maybe something has changed since then (or I made some silly mistake). -- Fernando
