On Tue, Sep 25, 2007 at 12:36:17PM +0200, Ingo Molnar wrote: > hm. perhaps this fixup in kernel/sched.c:set_task_cpu(): > > p->se.vruntime -= old_rq->cfs.min_vruntime - new_rq->cfs.min_vruntime;
This definitely does need some fixup, even though I am not sure yet if it will solve completely the latency issue. I tried the following patch. I *think* I see some improvement, wrt latency seen when I type on the shell. Before this patch, I noticed oddities like "kill -9 chew-max-pid" wont kill chew-max (it is queued in runqueue waiting for a looong time to run before it can acknowledge signal and exit). With this patch, I don't see such oddities ..So I am hoping it fixes the latency problem you are seeing as well. Index: current/kernel/sched.c =================================================================== --- current.orig/kernel/sched.c +++ current/kernel/sched.c @@ -1039,6 +1039,8 @@ void set_task_cpu(struct task_struct *p, { int old_cpu = task_cpu(p); struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu); + struct cfs_rq *old_cfsrq = task_cfs_rq(p), + *new_cfsrq = cpu_cfs_rq(old_cfsrq, new_cpu); u64 clock_offset; clock_offset = old_rq->clock - new_rq->clock; @@ -1051,7 +1053,8 @@ void set_task_cpu(struct task_struct *p, if (p->se.block_start) p->se.block_start -= clock_offset; #endif - p->se.vruntime -= old_rq->cfs.min_vruntime - new_rq->cfs.min_vruntime; + p->se.vruntime -= old_cfsrq->min_vruntime - + new_cfsrq->min_vruntime; __set_task_cpu(p, new_cpu); } -- Regards, vatsa - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/