Messages in this thread Patch in this message | | | From | Srikar Dronamraju <> | Subject | [PATCH 18/19] sched/numa: Reset scan rate whenever task moves across nodes | Date | Mon, 4 Jun 2018 15:30:27 +0530 |
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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.
Testcase Time: Min Max Avg StdDev numa01.sh Real: 428.48 837.17 700.45 162.77 numa01.sh Sys: 78.64 247.70 164.45 58.32 numa01.sh User: 37487.25 63728.06 54399.27 10088.13 numa02.sh Real: 60.07 62.65 61.41 0.85 numa02.sh Sys: 15.83 29.36 21.04 4.48 numa02.sh User: 5194.27 5280.60 5236.55 28.01 numa03.sh Real: 814.33 881.93 849.69 27.06 numa03.sh Sys: 111.45 134.02 125.28 7.69 numa03.sh User: 63007.36 68013.46 65590.46 2023.37 numa04.sh Real: 412.19 438.75 424.43 9.28 numa04.sh Sys: 232.97 315.77 268.98 26.98 numa04.sh User: 33997.30 35292.88 34711.66 415.78 numa05.sh Real: 394.88 449.45 424.30 22.53 numa05.sh Sys: 262.03 390.10 314.53 51.01 numa05.sh User: 33389.03 35684.40 34561.34 942.34
Testcase Time: Min Max Avg StdDev %Change numa01.sh Real: 449.46 770.77 615.22 101.70 13.85% numa01.sh Sys: 132.72 208.17 170.46 24.96 -3.52% numa01.sh User: 39185.26 60290.89 50066.76 6807.84 8.653% numa02.sh Real: 60.85 61.79 61.28 0.37 0.212% numa02.sh Sys: 15.34 24.71 21.08 3.61 -0.18% numa02.sh User: 5204.41 5249.85 5231.21 17.60 0.102% numa03.sh Real: 785.50 916.97 840.77 44.98 1.060% numa03.sh Sys: 108.08 133.60 119.43 8.82 4.898% numa03.sh User: 61422.86 70919.75 64720.87 3310.61 1.343% numa04.sh Real: 429.57 587.37 480.80 57.40 -11.7% numa04.sh Sys: 240.61 321.97 290.84 33.58 -7.51% numa04.sh User: 34597.65 40498.99 37079.48 2060.72 -6.38% numa05.sh Real: 392.09 431.25 414.65 13.82 2.327% numa05.sh Sys: 229.41 372.48 297.54 53.14 5.710% numa05.sh User: 33390.86 34697.49 34222.43 556.42 0.990%
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> --- 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 339c3dc..fc1f388 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1808,12 +1808,6 @@ 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) { pg_data_t *pgdat = NODE_DATA(cpu_to_node(env.dst_cpu)); @@ -6669,6 +6663,19 @@ 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 } static void task_dead_fair(struct task_struct *p) -- 1.8.3.1
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