Earlier today I did some testing with the 3.8.13 kernel and an audio cape. When running the alsa loop test latency.c I had much lower latency and less XRUNs with PREMPT enabled. Something like 3ms analog audio in to analog audio out versus maybe 6ms.
Thinking of upgrading to the 3.14 kernel but I was not sure if I would have any issue with the audio cape, SPI, and analog input device tree overlays... CAPE=BB-BONE-AUDI-02,cape-bone-iio,BB-SPI1-01-00A0 On Wed, Sep 17, 2014 at 9:14 AM, Jason Kridner <[email protected]> wrote: > On Wed, Sep 17, 2014 at 11:13 AM, Robert Nelson <[email protected]> > wrote: > > On Wed, Sep 17, 2014 at 9:53 AM, neo <[email protected]> wrote: > >> Hi Jason > >> > >> Sorry to ask again. Will PREMPT be enabled in this ? > > > > Full "preempt" no, not by default, but i'm testing > "CONFIG_PREEMPT_VOLUNTARY".. > > > > I'm still a little worried about the: "cost of slighly lower > > throughput." for some applications we need all 1Ghz... > > I suspect most applications of BeagleBone Black will be more worried > about latency than throughput due to its "industrial" nature. > BeaglePilot, OpenROV, Lasersaur, MachineKit, Pocket NC, QuickBot, etc. > Sure, applications like Ninja Blocks, GrannyCam, and other "IoT"-ish > stuff might not care so much about latency, but they are probably more > interested in power management than absolutely highest performance. > Just my impression. > > Would love to encourage more people to share what they are doing at > http://beagleboard.org/project and to reach out for project spotlights > on http://beagleboard.org/blog to give us all more of an impression of > what people need and are doing. > > I'm more worried about if anything breaks like what the BeaglePilot > folks have been reporting about some PRU driver issues related to > PREEMPT. > > I will say that simply using the RT scheduler without PREEMPT still > makes things "pretty darn fast" (TM) as can be seen in the UCSD > BeagleMIP which runs the balancing algorithm as a normal Linux thread > w/o the PRUs, kernel task or PREEMPT. > > > > > Regards, > > > > -- > > Robert Nelson > > http://www.rcn-ee.com/ > > > > -- > > For more options, visit http://beagleboard.org/discuss > > --- > > You received this message because you are subscribed to the Google > Groups "BeagleBoard" group. > > To unsubscribe from this group and stop receiving emails from it, send > an email to [email protected]. > > For more options, visit https://groups.google.com/d/optout. > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
