On Wed, 16 Nov 2011, Eric Dumazet wrote: > > Adding SLUB_STATS gives : > > > > $ cd /sys/kernel/slab/skbuff_head_cache ; grep . * > > aliases:6 > > align:8 > > grep: alloc_calls: Function not implemented > > alloc_fastpath:89181782 C0=89173048 C1=1599 C2=1357 C3=2140 C4=802 C5=675 C6=638 C7=1523 > > alloc_from_partial:412658 C0=412658 > > alloc_node_mismatch:0 > > alloc_refill:593417 C0=593189 C1=19 C2=15 C3=24 C4=51 C5=18 C6=17 C7=84 > > alloc_slab:2831313 C0=2831285 C1=2 C2=2 C3=2 C4=2 C5=12 C6=4 C7=4 > > alloc_slowpath:4430371 C0=4430112 C1=20 C2=17 C3=25 C4=57 C5=31 C6=21 C7=88 > > cache_dma:0 > > cmpxchg_double_cpu_fail:0 > > cmpxchg_double_fail:1 C0=1 > > cpu_partial:30 > > cpu_partial_alloc:592991 C0=592981 C2=1 C4=5 C5=2 C6=1 C7=1 > > cpu_partial_free:4429836 C0=592981 C1=25 C2=19 C3=23 C4=3836767 C5=6 C6=8 C7=7 > > cpuslab_flush:0 > > cpu_slabs:107 > > deactivate_bypass:3836954 C0=3836923 C1=1 C2=2 C3=1 C4=6 C5=13 C6=4 C7=4 > > deactivate_empty:2831168 C4=2831168 > > deactivate_full:0 > > deactivate_remote_frees:0 > > deactivate_to_head:0 > > deactivate_to_tail:0 > > destroy_by_rcu:0 > > free_add_partial:0 > > grep: free_calls: Function not implemented > > free_fastpath:21192924 C0=21186268 C1=1420 C2=1204 C3=1966 C4=572 C5=349 C6=380 C7=765 > > free_frozen:67988498 C0=516 C1=121 C2=85 C3=841 C4=67986468 C5=215 C6=76 C7=176 > > free_remove_partial:18 C4=18 > > free_slab:2831186 C4=2831186 > > free_slowpath:71825749 C0=609 C1=146 C2=104 C3=864 C4=71823538 C5=221 C6=84 C7=183 > > hwcache_align:0 > > min_partial:5 > > objects:2494 > > object_size:192 > > objects_partial:121 > > objs_per_slab:21 > > order:0 > > order_fallback:0 > > partial:14 > > poison:0 > > reclaim_account:0 > > red_zone:0 > > reserved:0 > > sanity_checks:0 > > slabs:127 > > slabs_cpu_partial:99(99) C1=25(25) C2=18(18) C3=23(23) C4=16(16) C5=4(4) C6=7(7) C7=6(6) > > slab_size:192 > > store_user:0 > > total_objects:2667 > > trace:0 > > > > And the SLUB stats for the 2048 bytes slab is even worse : About every > alloc/free is slow path > > $ cd /sys/kernel/slab/:t-0002048 ; grep . * > aliases:0 > align:8 > grep: alloc_calls: Function not implemented > alloc_fastpath:8199220 C0=8196915 C1=306 C2=63 C3=297 C4=319 C5=550 > C6=722 C7=48 > alloc_from_partial:13931406 C0=13931401 C3=1 C5=4 > alloc_node_mismatch:0 > alloc_refill:70871657 C0=70871629 C1=2 C3=3 C4=9 C5=11 C6=3 > alloc_slab:1335 C0=1216 C1=17 C2=2 C3=15 C4=17 C5=22 C6=44 C7=2 > alloc_slowpath:155455299 C0=155455144 C1=18 C2=1 C3=21 C4=27 C5=40 C6=47 > C7=1 I certainly sympathize with your situation; these stats are even worse with netperf TCP_RR where slub regresses very heavily against slab. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>