net: Add sendmmsg socket system call
This patch adds a multiple message send syscall and is the send
version of the existing recvmmsg syscall. This is heavily
based on the patch by Arnaldo that added recvmmsg.
I wrote a microbenchmark to test the performance gains of using
this new syscall:
http://ozlabs.org/~anton/junkcode/sendmmsg_test.c
The test was run on a ppc64 box with a 10 Gbit network card. The
benchmark can send both UDP and RAW ethernet packets.
64B UDP
batch pkts/sec
1 804570
2 872800 (+ 8 %)
4 916556 (+14 %)
8 939712 (+17 %)
16 952688 (+18 %)
32 956448 (+19 %)
64 964800 (+20 %)
64B raw socket
batch pkts/sec
1 1201449
2 1350028 (+12 %)
4 1461416 (+22 %)
8 1513080 (+26 %)
16 1541216 (+28 %)
32 1553440 (+29 %)
64 1557888 (+30 %)
We see a 20% improvement in throughput on UDP send and 30%
on raw socket send.
[ Add sparc syscall entries. -DaveM ]
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 83ecc17..ab71447 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -610,6 +610,8 @@
asmlinkage long sys_sendto(int, void __user *, size_t, unsigned,
struct sockaddr __user *, int);
asmlinkage long sys_sendmsg(int fd, struct msghdr __user *msg, unsigned flags);
+asmlinkage long sys_sendmmsg(int fd, struct mmsghdr __user *msg,
+ unsigned int vlen, unsigned flags);
asmlinkage long sys_recv(int, void __user *, size_t, unsigned);
asmlinkage long sys_recvfrom(int, void __user *, size_t, unsigned,
struct sockaddr __user *, int __user *);