![]() We tried very hard to remove all possible dev_hold()/dev_put() pairs in network stack, using RCU conversions. There is still an unavoidable device refcount change for every dst we create/destroy, and this can slow down some workloads (routers or some app servers, mmap af_packet) We can switch to a percpu refcount implementation, now dynamic per_cpu infrastructure is mature. On a 64 cpus machine, this consumes 256 bytes per device. On x86, dev_hold(dev) code : before lock incl 0x280(%ebx) after: movl 0x260(%ebx),%eax incl fs:(%eax) Stress bench : (Sending 160.000.000 UDP frames, IP route cache disabled, dual E5540 @2.53GHz, 32bit kernel, FIB_TRIE) Before: real 1m1.662s user 0m14.373s sys 12m55.960s After: real 0m51.179s user 0m15.329s sys 10m15.942s Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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9p | ||
802 | ||
8021q | ||
appletalk | ||
atm | ||
ax25 | ||
bluetooth | ||
bridge | ||
caif | ||
can | ||
core | ||
dcb | ||
dccp | ||
decnet | ||
dns_resolver | ||
dsa | ||
econet | ||
ethernet | ||
ieee802154 | ||
ipv4 | ||
ipv6 | ||
ipx | ||
irda | ||
iucv | ||
key | ||
l2tp | ||
lapb | ||
llc | ||
mac80211 | ||
netfilter | ||
netlabel | ||
netlink | ||
netrom | ||
packet | ||
phonet | ||
rds | ||
rfkill | ||
rose | ||
rxrpc | ||
sched | ||
sctp | ||
sunrpc | ||
tipc | ||
unix | ||
wanrouter | ||
wimax | ||
wireless | ||
x25 | ||
xfrm | ||
compat.c | ||
Kconfig | ||
Makefile | ||
nonet.c | ||
socket.c | ||
sysctl_net.c | ||
TUNABLE |