Richard Cochran wrote: > On Sun, Apr 24, 2011 at 10:15:00PM +0200, Gilles Chanteperdrix wrote: >> some temporary results on the benchmark here: >> http://www.xenomai.org/~gch/latency-at91sam9263.png >> >> The worst case latency seems not to vary much over time, it looks like >> it is decreasing a bit, but the differences may well be in the >> measurement noise. Unlocked context switch actually improves the latency. >> >> I will update the png as I get new results. > > Gilles, > > That is a very interesting graph. It might be nice to have a > "performance benchmarks" page on the wiki, including that figure, plus > the description of the test setup. I can contribute IXP and some > PowerPC results.
Yes, we should set this up. The xeno-test currently in the head branch is made to help doing this. > > Regarding the measured performance, the graphs are shaped like the > letter, H (or like a Bactrian camel, with two humps). > > I appears to me that the peaks of the 2.4.10 lines (red, green) are > standing clearly to the left of the 2.5.6 lines (blue, purple), by > about 10 microseconds. I would say that 2.4.10 outperforms 2.5.6, on > average. I added the average latencies (except for 2.4.10 with the I-pipe 1.14-04 patch). The peak corresponds roughly to the average "lat max" column in latency results. Both the I-pipe version and Xenomai version seem to contribute to the increased average latency. The unlocked context switch also improves the worst-case at the expense of the average. But there is hope, 2.6.33-1.18-03 introduces pic muting and re-enables irq in the middle of gpio demuxing, which seems to improve the average latency. > > The absolute worst case appears to be about the same, or perhaps > slightly improved in 2.5.6. > > So the differences are not huge, but still I think 2.4.10 is looking > better. it is true that 2.4.10 had better average latencies, but the worst case latencies seem to be improving, and I am afraid this is what we are aiming at... -- Gilles. _______________________________________________ Xenomai-core mailing list Xenomaifirstname.lastname@example.org https://mail.gna.org/listinfo/xenomai-core