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>

2 files changed, 3 insertions, 1 deletions

diff --git a/arch/powerpc/include/asm/systbl.h b/arch/powerpc/include/asm/systbl.h
index 60f64b132bd4..8489d372077f 100644
--- a/arch/powerpc/include/asm/systbl.h
+++ b/arch/powerpc/include/asm/systbl.h
@@ -352,3 +352,4 @@ SYSCALL_SPU(name_to_handle_at)
 COMPAT_SYS_SPU(open_by_handle_at)
 COMPAT_SYS_SPU(clock_adjtime)
 SYSCALL_SPU(syncfs)
+COMPAT_SYS_SPU(sendmmsg)
diff --git a/arch/powerpc/include/asm/unistd.h b/arch/powerpc/include/asm/unistd.h
index 3c215648ce6d..6d23c8193caa 100644
--- a/arch/powerpc/include/asm/unistd.h
+++ b/arch/powerpc/include/asm/unistd.h
@@ -371,10 +371,11 @@
 #define __NR_open_by_handle_at  346
 #define __NR_clock_adjtime      347
 #define __NR_syncfs             348
+#define __NR_sendmmsg           349
 
 #ifdef __KERNEL__
 
-#define __NR_syscalls           349
+#define __NR_syscalls           350
 
 #define __NR__exit __NR_exit
 #define NR_syscalls     __NR_syscalls