On Thu, 23 Feb 2017 06:00:15 -0800 Dan Zach <[email protected]> wrote:
> Dear forum, > > On the Jetson TK1 inmate I use linux 4.8.2 with PREEMPT-RT patch. > I measure a 1KHz high priority task based on hrtimer events that > measures it's own jitter. > > The worst case, I get 400uS jitter on 1mS tick - not so bad, but the > interesting thing is that the jitter stays as low as 50uS, untill I > start activity on the root cell, especially GUI. > > So the questions is: if the non-root cell is completely isolated from > the root: separate physical memory, PPI from its local timer, where > this cross influence can come from? Well the cells are not completely isolated, some shared resources remain. The jitter you are seeing is caused by those, i.e. caches and busses. And GPU workloads would likely stress exactly those. Henning > Thanks > Dan > -- You received this message because you are subscribed to the Google Groups "Jailhouse" 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.
