> You don't give any info wrt what kind of box this is, how you ran > cyclictest, what load it was competing against, nada. With the info > provided, nobody can say much. > > It _looks_ like you must have just called up cyclictest using all > defaults, which doesn't even start cyclictest as a realtime class task, > meaning you'll see worst case latencies for SCHED_OTHER tasks, which has > nothing to do with realtime class scheduling latencies. > > Latencies in the 40us range are pretty normal for my el-cheapo Q6600 > desktop grade box trying to save power and sucking rocks at it, but ms > latencies I never see with remotely sane loads. > > -Mike > Hello Mike, You're right, but the problem is that I tried running cyclictest with many different parameters to see if it was working (-S, -p95, etc..). I also tried to disable some CPU hearts to see with just one active heart if the problem still was here. But like I said, the test was returning this bad results ONLY over this hardware ! I tried with the same distribution, in the same conditions, and with the same tests on other computers with different hardware (software wasn't different as I used an external SDD to boot on debian), and it worked fine. I agree... ms latencies is very weird... The load of the system was different each time, but the results were the same : I tried in single user mode, I tried with X server loaded, under a X server terminal, etc. etc. Moreover, the use of hwlatdetect seems to confirm that the problem is from hardware. Another test that we tried to do is to activate idle=poll at the boot in grub, and to trace the cyclictest. In the traces, we can see a gap of more or less 35ms. I'm pretty sure the problem is linked to hardware. But if you have an idea of parameters I can use with cyclictest to have better results, please let me know ! Thank you ! Raphaël -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
