[vfs] 73c12e50a: +13349.5% softirqs.RCU

From: Fengguang Wu
Date: Wed Feb 19 2014 - 08:12:45 EST


Hi Eric,

FYI, we noticed the below changes on commit 73c12e50af3a756137071c1e1c1e99cffcbaa835
("vfs: Lazily remove mounts on unlinked files and directories."):

test case: dbench

5c39777e797e7ba 73c12e50af3a756137071c1e1
--------------- -------------------------
6.22 ~ 0% +195.3% 18.36 ~18% TOTAL dbench.max_latency

Note: the "~ XX%" numbers are stddev percent.

test case: will-it-scale/unlink2

5c39777e797e7ba 73c12e50af3a756137071c1e1
--------------- -------------------------
57178 ~ 2% -83.9% 9188 ~ 3% TOTAL numa-vmstat.node1.nr_slab_unreclaimable
97777 ~ 1% -85.3% 14413 ~ 6% TOTAL numa-vmstat.node0.nr_slab_unreclaimable
227271 ~ 2% -83.9% 36567 ~ 4% TOTAL numa-meminfo.node1.SUnreclaim
78384 ~ 2% +13349.5% 10542303 ~11% TOTAL softirqs.RCU
202419 ~15% +48738.0% 98857773 ~ 4% TOTAL cpuidle.C1-SNB.time
955612 ~31% +2561.5% 25433795 ~10% TOTAL cpuidle.C1E-SNB.time
1278 ~20% +8648.3% 111872 ~11% TOTAL cpuidle.C1E-SNB.usage
364333 ~11% +786.3% 3229011 ~17% TOTAL cpuidle.C3-SNB.time
793 ~ 5% +568.6% 5305 ~12% TOTAL cpuidle.C3-SNB.usage
10882 ~15% +1943.2% 222341 ~18% TOTAL cpuidle.C6-SNB.time
8 ~27% +4702.4% 403 ~17% TOTAL cpuidle.C6-SNB.usage
389688 ~ 2% -85.3% 57320 ~ 5% TOTAL numa-meminfo.node0.SUnreclaim
485651 ~ 2% -82.5% 84770 ~ 5% TOTAL numa-meminfo.node0.Slab
19822 ~ 4% -91.7% 1649 ~ 7% TOTAL slabinfo.kmalloc-256.num_slabs
19822 ~ 4% -91.7% 1649 ~ 7% TOTAL slabinfo.kmalloc-256.active_slabs
634311 ~ 4% -91.7% 52792 ~ 7% TOTAL slabinfo.kmalloc-256.num_objs
768494 ~ 3% -81.0% 146268 ~ 2% TOTAL meminfo.Slab
634179 ~ 4% -91.7% 52517 ~ 7% TOTAL slabinfo.kmalloc-256.active_objs
16094 ~ 3% -85.4% 2343 ~ 3% TOTAL slabinfo.dentry.num_slabs
16094 ~ 3% -85.4% 2343 ~ 3% TOTAL slabinfo.dentry.active_slabs
675979 ~ 3% -85.4% 98427 ~ 3% TOTAL slabinfo.dentry.num_objs
675739 ~ 3% -85.5% 98065 ~ 3% TOTAL slabinfo.dentry.active_objs
12925 ~ 4% -91.6% 1081 ~ 7% TOTAL slabinfo.shmem_inode_cache.num_slabs
12925 ~ 4% -91.6% 1081 ~ 7% TOTAL slabinfo.shmem_inode_cache.active_slabs
153617 ~ 3% -84.5% 23851 ~ 3% TOTAL proc-vmstat.nr_slab_unreclaimable
633368 ~ 4% -91.6% 53034 ~ 7% TOTAL slabinfo.shmem_inode_cache.num_objs
633182 ~ 4% -91.7% 52584 ~ 7% TOTAL slabinfo.shmem_inode_cache.active_objs
611608 ~ 3% -84.4% 95315 ~ 3% TOTAL meminfo.SUnreclaim
56626 ~ 0% +977.2% 609963 ~ 4% TOTAL interrupts.RES
289471 ~ 1% -79.4% 59729 ~ 4% TOTAL numa-meminfo.node1.Slab
95962 ~ 3% -71.4% 27449 ~ 7% TOTAL numa-meminfo.node0.SReclaimable
24059 ~ 3% -71.4% 6870 ~ 7% TOTAL numa-vmstat.node0.nr_slab_reclaimable
39360 ~ 2% -67.6% 12741 ~ 1% TOTAL proc-vmstat.nr_slab_reclaimable
156885 ~ 2% -67.5% 50952 ~ 1% TOTAL meminfo.SReclaimable
62199 ~ 1% -62.8% 23161 ~ 7% TOTAL numa-meminfo.node1.SReclaimable
15622 ~ 1% -62.9% 5795 ~ 7% TOTAL numa-vmstat.node1.nr_slab_reclaimable
40507 ~39% +153.7% 102749 ~19% TOTAL cpuidle.C1-NHM.time
23068 ~ 2% +135.2% 54252 ~ 9% TOTAL interrupts.IWI
357 ~27% +116.4% 774 ~15% TOTAL cpuidle.C3-NHM.usage
4834003 ~ 3% -47.6% 2534625 ~ 4% TOTAL numa-numastat.node1.local_node
4834003 ~ 3% -47.6% 2534625 ~ 4% TOTAL numa-numastat.node1.numa_hit
2167 ~23% -28.0% 1560 ~ 6% TOTAL proc-vmstat.nr_tlb_remote_flush_received
58685570 ~ 2% -38.5% 36079286 ~ 2% TOTAL proc-vmstat.pgalloc_normal
68325712 ~ 1% -37.7% 42551512 ~ 2% TOTAL proc-vmstat.pgfree
1079369 ~ 0% -36.9% 681261 ~ 0% TOTAL numa-meminfo.node0.MemUsed
140248 ~ 2% -35.2% 90832 ~ 5% TOTAL softirqs.SCHED
19460075 ~ 1% -36.5% 12353959 ~ 2% TOTAL proc-vmstat.numa_local
19460075 ~ 1% -36.5% 12353960 ~ 2% TOTAL proc-vmstat.numa_hit
53926 ~24% -33.4% 35902 ~ 2% TOTAL meminfo.DirectMap4k
85 ~31% +79.6% 153 ~28% TOTAL cpuidle.C1-NHM.usage
9675753 ~ 1% -33.1% 6474766 ~ 1% TOTAL proc-vmstat.pgalloc_dma32
14654234 ~ 1% -32.9% 9829336 ~ 1% TOTAL numa-numastat.node0.local_node
14654234 ~ 1% -32.9% 9829336 ~ 1% TOTAL numa-numastat.node0.numa_hit
1878635 ~ 1% -31.6% 1284774 ~ 2% TOTAL numa-vmstat.node1.numa_local
1886571 ~ 1% -31.5% 1292725 ~ 2% TOTAL numa-vmstat.node1.numa_hit
1425 ~ 7% -20.0% 1140 ~10% TOTAL numa-meminfo.node1.Mlocked
356 ~ 7% -20.0% 285 ~10% TOTAL numa-vmstat.node1.nr_mlock
287 ~ 9% +24.8% 358 ~ 8% TOTAL numa-vmstat.node0.nr_mlock
1150 ~ 9% +24.8% 1435 ~ 8% TOTAL numa-meminfo.node0.Mlocked
1441 ~ 7% -19.8% 1156 ~10% TOTAL numa-meminfo.node1.Unevictable
360 ~ 7% -19.8% 289 ~10% TOTAL numa-vmstat.node1.nr_unevictable
1166 ~ 9% +24.4% 1451 ~ 8% TOTAL numa-meminfo.node0.Unevictable
291 ~ 9% +24.4% 362 ~ 8% TOTAL numa-vmstat.node0.nr_unevictable
871951 ~ 0% -25.9% 645735 ~ 0% TOTAL numa-meminfo.node1.MemUsed
8508242 ~ 0% -24.4% 6432405 ~ 1% TOTAL numa-vmstat.node0.numa_local
225490 ~ 2% -24.1% 171244 ~ 2% TOTAL cpuidle.C7-SNB.usage
8623332 ~ 0% -24.1% 6547495 ~ 1% TOTAL numa-vmstat.node0.numa_hit
313 ~28% -30.7% 217 ~21% TOTAL cpuidle.C1E-NHM.usage
1943 ~ 0% +7380.4% 145404 ~11% TOTAL time.voluntary_context_switches
1001 ~ 0% +1015.5% 11173 ~ 4% TOTAL vmstat.system.cs
4815 ~ 0% +34.0% 6452 ~ 1% TOTAL vmstat.system.in
1480 ~ 0% -1.7% 1454 ~ 0% TOTAL time.system_time
485 ~ 0% -1.6% 477 ~ 0% TOTAL time.percent_of_cpu_this_job_got
50.66 ~ 0% -1.4% 49.97 ~ 0% TOTAL turbostat.%c0
7.69 ~ 0% +1.1% 7.78 ~ 0% TOTAL boottime.dhcp
106 ~ 0% -0.5% 106 ~ 0% TOTAL turbostat.Cor_W
134 ~ 0% -0.4% 133 ~ 0% TOTAL turbostat.Pkg_W

time.voluntary_context_switches

20000 ++-----------------------------------------------------------------+
18000 ++ O O O |
| O |
16000 ++ O |
14000 ++ O O |
O O O O O O |
12000 ++ O |
10000 ++ O O |
8000 ++ |
| O O O O O O |
6000 ++ |
4000 ++ |
| |
2000 *+.*..*.*..*..*..*..*.*..*..*..*..*.*..*..*..*.*..*..*..*..*.*..*..*
0 ++-----------------------------------------------------------------+

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