<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div>Hi,</div><div><br></div><div>On the puredata.info FAQ at</div><div>http://puredata.info/docs/faq/LowerLatency.faq</div><div>there is this:</div><div><br></div><div> Under Linux, with a recent version of the stable kernel (2.4.x), special low latency patches, some hard drive tuning, and ALSA drivers, average audio latencies is 1.5 ms. If you really load your system, a maximum audio latency of 3 ms can be reached. Pathological bad cases have been known to cause 8 ms latencies this seems like the upper bound. More information on low latency under Linux can be found at Benno's site on the subject.<br><br>TODO (tell the people that Pd has 3 blocks buffer, which gives you 4.5ms at least on 44.1kHz)</div><div><br></div><div>Questions:</div><div>Can I get realtime priorities using the RT PREEMPT patch just using
ALSA, and not JACK?</div><div><br></div><div>If I use JACK, does it make any difference whether or not I start Pd with the -rt flag <br></div><div>(as long as I enable realtime in JACK, of course)?</div><div><br></div><div>What kind of hard drive tuning? I've never read about that anywhere else.</div><div><br></div><div>What is the "pathological bad cases" refer to?</div><div><br></div><div>Benno's site only goes up to the 2.4 kernel. Is there a more up-to-date source that we can link to from <br></div><div>this FAQ?</div><div><br></div><div>More on the TODO? If 4.5ms is the smallest latency at 44.1, what sample rate is being used to get the <br></div><div>1.5ms average referred to in the paragraph above?</div><div><br></div><div>Any more info on the 3 block buffer?</div><div><br></div><div>Thanks,</div><div>Jonathan<br></div><div><br></div><div><br></div></div></body></html>