* Kevin Shanahan <kmshanah@xxxxxxxxxxx> wrote: > > This suggests some sort of KVM-specific problem. Scheduler latencies > > in the seconds that occur under normal load situations are noticed and > > reported quickly - and there are no such open regressions currently. > > It at least suggests a problem with interaction between the scheduler > and kvm, otherwise reverting that scheduler patch wouldn't have made the > regression go away. the scheduler affects almost everything, so almost by definition a scheduler change can tickle a race or other timing bug in just about any code - and reverting that change in the scheduler can make the bug go away. But yes, it could also be a genuine scheduler bug - that is always a possibility. Could you please run a cfs-debug-info.sh session on a CONFIG_SCHED_DEBUG=y and CONFIG_SCHEDSTATS=y kernel, while you are experiencing those latencies: http://people.redhat.com/mingo/cfs-scheduler/tools/cfs-debug-info.sh and post that (relatively large) somewhere, or send it as a reply after bzip2 -9 compressing it? It will include a lot of information about the delays your tasks are experiencing. Ingo -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
