* Henri Roosen | 2016-07-15 12:54:25 [+0200]: >The problem is easily triggered, but only after starting a flood-ping to >the PREEMPT_RT-system under test. This also results in huge latency, >much bigger than on a 'normal' PREEMPT-system, which seems to be >resistant against the flood-ping. > >Any suggestions how to best trace this down? Hmm. 4.1.27-rt30 has softirq: split timer softirqs out of ksoftirqd net: provide a way to delegate processing a softirq to ksoftirqd I would suggest using those two but you should have them. Your ksoftirqd runs as SCHED_OTHER, right? And you do have CONFIG_RCU_BOOST enabled? Your do_hell script which starts hackbench does not run with higher priority? >From the backtrace it is hackbench "doing things" and this one should be preempted by RCU and ethernet networking napi code should be preempted / moved to ksoftirqd during the flood-ping. Can you check this happens? >Thanks, >Henri Sebastian -- 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
