On Wed, Feb 29, 2012 at 10:17:03AM +0100, Peter Zijlstra wrote: > On Tue, 2012-02-28 at 14:16 -0800, Dan Williams wrote: > > Looks like everyone is guilty: > > > > [ 422.765336] softirq took longer than 1/4 tick: 3 NET_RX ffffffff813f0aa0 > > ... > > [ 423.971878] softirq took longer than 1/4 tick: 4 BLOCK ffffffff812519c8 > > [ 423.985093] softirq took longer than 1/4 tick: 6 TASKLET ffffffff8103422e > > [ 423.993157] softirq took longer than 1/4 tick: 7 SCHED ffffffff8105e2e1 > > [ 424.001018] softirq took longer than 1/4 tick: 9 RCU ffffffff810a0fed > > [ 424.008691] softirq loop took longer than 1/2 tick need_resched: > > /me kicks himself for not printing the actual duration.. :-) > > > As expected whenever that 1/2 tick message gets emitted the softirq > > handler is almost running in a need_resched() context. > > Yeah.. that's quite expected. > > > So is it a good idea to get more aggressive about scheduling ksoftrrqd? > > Nah, moving away from softirq more like. I'll put moving the > load-balancer into a kthread on the todo list. And it looks like > everybody else should move to kthreads too. Last year when I tried that, things got a bit ugly. I guess I don't need the kthreads to be realtime unless CONFIG_RCU_BOOST=y, maybe that will help. Also IIRC Steven Rostedt made some real-time changes that might help as well for my case, which would have a per-CPU RT kthread. Thanx, Paul -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
