* Srikar Dronamraju <[email protected]> wrote:
> Currently task scan rate is reset when numa balancer migrates the task > to a different node. If numa balancer initiates a swap, reset is only > applicable to the task that initiates the swap. Similarly no scan rate > reset is done if the task is migrated across nodes by traditional load > balancer. > > Instead move the scan reset to the migrate_task_rq. This ensures the > task moved out of its preferred node, either gets back to its preferred > node quickly or finds a new preferred node. Doing so, would be fair to > all tasks migrating across nodes. > > specjbb2005 / bops/JVM / higher bops are better > on 2 Socket/2 Node Intel > JVMS Prev Current %Change > 4 210118 208862 -0.597759 > 1 313171 307007 -1.96825 > > > on 2 Socket/4 Node Power8 (PowerNV) > JVMS Prev Current %Change > 8 91027.5 89911.4 -1.22611 > 1 216460 216176 -0.131202 > > > on 2 Socket/2 Node Power9 (PowerNV) > JVMS Prev Current %Change > 4 191918 196078 2.16759 > 1 207043 214664 3.68088 > > > on 4 Socket/4 Node Power7 > JVMS Prev Current %Change > 8 58462.1 60719.2 3.86079 > 1 108334 112615 3.95167 > > > dbench / transactions / higher numbers are better > on 2 Socket/2 Node Intel > count Min Max Avg Variance %Change > 5 11851.8 11937.3 11890.9 33.5169 > 5 12511.7 12559.4 12539.5 15.5883 5.45459 > > > on 2 Socket/4 Node Power8 (PowerNV) > count Min Max Avg Variance %Change > 5 4791 5016.08 4962.55 85.9625 > 5 4709.28 4979.28 4919.32 105.126 -0.871125 > > > on 2 Socket/2 Node Power9 (PowerNV) > count Min Max Avg Variance %Change > 5 9353.43 9380.49 9369.6 9.04361 > 5 9388.38 9406.29 9395.1 5.98959 0.272157 > > > on 4 Socket/4 Node Power7 > count Min Max Avg Variance %Change > 5 149.518 215.412 179.083 21.5903 > 5 157.71 184.929 174.754 10.7275 -2.41731 > > Signed-off-by: Srikar Dronamraju <[email protected]> > --- > kernel/sched/fair.c | 19 +++++++++++++------ > 1 file changed, 13 insertions(+), 6 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index a5936ed..4ea0eff 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -1837,12 +1837,6 @@ static int task_numa_migrate(struct task_struct *p) > if (env.best_cpu == -1) > return -EAGAIN; > > - /* > - * Reset the scan period if the task is being rescheduled on an > - * alternative node to recheck if the tasks is now properly placed. > - */ > - p->numa_scan_period = task_scan_start(p); > - > best_rq = cpu_rq(env.best_cpu); > if (env.best_task == NULL) { > ret = migrate_task_to(p, env.best_cpu); > @@ -6361,6 +6355,19 @@ static void migrate_task_rq_fair(struct task_struct > *p, int new_cpu __maybe_unus > > /* We have migrated, no longer consider this task hot */ > p->se.exec_start = 0; > + > +#ifdef CONFIG_NUMA_BALANCING > + if (!p->mm || (p->flags & PF_EXITING)) > + return; > + > + if (p->numa_faults) { > + int src_nid = cpu_to_node(task_cpu(p)); > + int dst_nid = cpu_to_node(new_cpu); > + > + if (src_nid != dst_nid) > + p->numa_scan_period = task_scan_start(p); > + } > +#endif Please don't add #ifdeffery inside functions, especially not if they do weird flow control like a 'return' from the middle of a block. A properly named inline helper would work I suppose. Thanks, Ingo
