From fc66f95c68b6d4535a0ea2ea15d5cf626e310956 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 8 Oct 2010 06:37:34 +0000 Subject: net dst: use a percpu_counter to track entries struct dst_ops tracks number of allocated dst in an atomic_t field, subject to high cache line contention in stress workload. Switch to a percpu_counter, to reduce number of time we need to dirty a central location. Place it on a separate cache line to avoid dirtying read only fields. Stress test : (Sending 160.000.000 UDP frames, IP route cache disabled, dual E5540 @2.53GHz, 32bit kernel, FIB_TRIE, SLUB/NUMA) Before: real 0m51.179s user 0m15.329s sys 10m15.942s After: real 0m45.570s user 0m15.525s sys 9m56.669s With a small reordering of struct neighbour fields, subject of a following patch, (to separate refcnt from other read mostly fields) real 0m41.841s user 0m15.261s sys 8m45.949s Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/decnet/dn_route.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'net/decnet') diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c index 6585ea6..df0f3e5 100644 --- a/net/decnet/dn_route.c +++ b/net/decnet/dn_route.c @@ -132,7 +132,6 @@ static struct dst_ops dn_dst_ops = { .negative_advice = dn_dst_negative_advice, .link_failure = dn_dst_link_failure, .update_pmtu = dn_dst_update_pmtu, - .entries = ATOMIC_INIT(0), }; static __inline__ unsigned dn_hash(__le16 src, __le16 dst) @@ -1758,6 +1757,7 @@ void __init dn_route_init(void) dn_dst_ops.kmem_cachep = kmem_cache_create("dn_dst_cache", sizeof(struct dn_route), 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); + dst_entries_init(&dn_dst_ops); setup_timer(&dn_route_timer, dn_dst_check_expire, 0); dn_route_timer.expires = jiffies + decnet_dst_gc_interval * HZ; add_timer(&dn_route_timer); @@ -1816,5 +1816,6 @@ void __exit dn_route_cleanup(void) dn_run_flush(0); proc_net_remove(&init_net, "decnet_cache"); + dst_entries_destroy(&dn_dst_ops); } -- cgit v1.1