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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-10-08 06:37:34 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-10-11 13:06:53 -0700 |
| commit | fc66f95c68b6d4535a0ea2ea15d5cf626e310956 (patch) | |
| tree | ac3a7f08ad741a67ff683bf93e5669ddcae95ed7 /net/core/dst.c | |
| parent | 0ed8ddf4045fcfcac36bad753dc4046118c603ec (diff) | |
| download | lwn-fc66f95c68b6d4535a0ea2ea15d5cf626e310956.tar.gz lwn-fc66f95c68b6d4535a0ea2ea15d5cf626e310956.zip | |
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 <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/dst.c')
| -rw-r--r-- | net/core/dst.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/net/core/dst.c b/net/core/dst.c index 978a1ee1f7d0..32e542d7f472 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -168,7 +168,7 @@ void *dst_alloc(struct dst_ops *ops) { struct dst_entry *dst; - if (ops->gc && atomic_read(&ops->entries) > ops->gc_thresh) { + if (ops->gc && dst_entries_get_fast(ops) > ops->gc_thresh) { if (ops->gc(ops)) return NULL; } @@ -183,7 +183,7 @@ void *dst_alloc(struct dst_ops *ops) #if RT_CACHE_DEBUG >= 2 atomic_inc(&dst_total); #endif - atomic_inc(&ops->entries); + dst_entries_add(ops, 1); return dst; } EXPORT_SYMBOL(dst_alloc); @@ -236,7 +236,7 @@ again: neigh_release(neigh); } - atomic_dec(&dst->ops->entries); + dst_entries_add(dst->ops, -1); if (dst->ops->destroy) dst->ops->destroy(dst); |