From: Michal Soltys <soltys@xxxxxxxx> Date: Thu, 25 Sep 2008 00:07:51 +0200 > - what is the current resolution allowed by hrtimer_start ? During > simple tests with tbf I could easily schedule at pretty much any > rate (tested up to 100mbit) with just a packet sized token > bucket. And that regardless of selected HZ and/or NO_HZ > setting. Quite awesome. > > - in case of some older hardware - I assume the functionality falls > back to the old behavior, so - overall accuracy is still 1.024us > (judging from comments, and contrary to older kernels where > jiffies/ gettimeofday/ timestamp could be selected) - but allowed > watchdog resolution remains 1/HZ ? Also - what is NO_HZ's > influence (if any) in such scenario ? Basiclly you'll be able to use whatever resolution the hardware can provide. That is the only limit. NO_HZ has effectively no influence, NO_HZ only kicks in when there is no work for the CPU to do, so if you have an hrtimer pending on a qdisc that will get serviced at the intended moment, the cpu will come out of NO_HZ mode if necessary to do this. -- To unsubscribe from this list: send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
