Excerpts from David Olofson's message of 2011-07-21 01:03:32 +0200: > On Thursday 21 July 2011, at 00.36.55, Philipp Überbacher > <[email protected]> wrote: > [...] > > > ..and this latency plot is stunning: > > > https://www.osadl.org/Latency-plot-of-system-in-rack-4-slot.qa-latencyplo > > > t-r4s6.0.html?latencies=&showno=&slider=57 > [...] > > The plot really does look stunning, strangly (?) not on other machines. > > https://www.osadl.org/Latency-plot-of-system-in-rack-4-slot.qa-latencyplot- > > r4s7.0.html > > https://www.osadl.org/Latency-plot-of-system-in-rack-4-slot.qa-latencyplot > > -r4s8.0.html > > > > No idea what those plots tell about real world usage. It's good to get > > another set of patches though. > > In terms of worst case figures, these plots look a bit like what I've seen > with RT-Linux and RTAI on various hardware (PII/III workstations via Geode > SBCs through Intel Core based Celerons on industrial Mini-ITX boards), though > with "true" RT kernels, one tends to get a lot of very low latency points, > and > only the occasional peak. > > SBCs with lowpower CPUs (Geode and the like) tend to perform a lot worse than > "proper" laptop and desktop CPUs. Memory and/or cache bandwidth issues, maybe?
I do wonder whether the occasional peaks are due to the mainboards or the CPUs. At least in the wild mainboards seem to have a lot of influence (hardware interrupts or however they're called). _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/listinfo/linux-audio-dev
