linux-sg2042/net/decnet
Eric Dumazet fc66f95c68 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>
2010-10-11 13:06:53 -07:00
..
netfilter include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
Kconfig [NET]: Rethink mark field in struct flowi 2006-12-02 21:21:39 -08:00
Makefile Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
README Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
TODO Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
af_decnet.c net: sk_sleep() helper 2010-04-20 16:37:13 -07:00
dn_dev.c net: Remove unnecessary returns from void function()s 2010-05-17 23:23:14 -07:00
dn_fib.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
dn_neigh.c net neigh: RCU conversion of neigh hash table 2010-10-05 14:54:36 -07:00
dn_nsp_in.c Merge branch 'master' of /repos/git/net-next-2.6 2010-04-20 16:02:01 +02:00
dn_nsp_out.c net/decnet: Adjust confusing if indentation 2010-08-16 21:06:30 -07:00
dn_route.c net dst: use a percpu_counter to track entries 2010-10-11 13:06:53 -07:00
dn_rules.c net: rtnetlink: decouple rtnetlink address families from real address families 2010-04-26 16:13:54 +02:00
dn_table.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
dn_timer.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
sysctl_net_decnet.c sysctl net: Remove unused binary sysctl code 2009-11-12 02:05:06 -08:00

README

                       Linux DECnet Project
                      ======================

The documentation for this kernel subsystem is available in the
Documentation/networking subdirectory of this distribution and also
on line at http://www.chygwyn.com/DECnet/

Steve Whitehouse <SteveW@ACM.org>