Gilles Chanteperdrix wrote: > > And another here, whereas if I understand correctly, the mm did not > change. So, this is probably an unwanted effect of the cache flush > "optimization" in the arm patch. > > I will now try to understand if this second cache flush is really normal.
Yes, it is normal: the first context switch, which xnshadow_relax does, is a switch to whatever task Linux was running when preempted, not necessarily latency (and it turns out to never be latency when we capture the worst case) hence the first cache flush. We then re-interrupt Linux after this context switch, and switch again to latency, and we get a second cache flush. So, the conclusion is: everything is normal. What we obtain when pressing the enter key while latency is running in the background is a wakeup of the shell process and this process uses cache, so that the next latency context switches need to flush cache. In other words: pressing the enter key yields the same latency as running the cache calibrator because it has the same effect, it fills the cache. -- Gilles Chanteperdrix. _______________________________________________ Xenomai-core mailing list Xenomaifirstname.lastname@example.org https://mail.gna.org/listinfo/xenomai-core