net, runtime: enable runtime-integrated pollster on Linux/ARM.

Results from linux/arm on a Samsung Chromebook (from dfc):
localhost(~/go/src/pkg/net) % ~/go/misc/benchcmp {old,new}.txt
benchmark                           old ns/op    new ns/op    delta
BenchmarkTCP4OneShot                   568840       350526  -38.38%
BenchmarkTCP4OneShot-2                 359054       206708  -42.43%
BenchmarkTCP4OneShotTimeout            637464       363550  -42.97%
BenchmarkTCP4OneShotTimeout-2          374255       216695  -42.10%
BenchmarkTCP4Persistent                184974        64984  -64.87%
BenchmarkTCP4Persistent-2              109902        47195  -57.06%
BenchmarkTCP4PersistentTimeout         210039        64789  -69.15%
BenchmarkTCP4PersistentTimeout-2       124284        43374  -65.10%
BenchmarkTCP6OneShot                   672278       362116  -46.14%
BenchmarkTCP6OneShot-2                 383631       216400  -43.59%
BenchmarkTCP6OneShotTimeout            680740       378306  -44.43%
BenchmarkTCP6OneShotTimeout-2          397524       230152  -42.10%
BenchmarkTCP6Persistent                172346        65292  -62.12%
BenchmarkTCP6Persistent-2              106229        42096  -60.37%
BenchmarkTCP6PersistentTimeout         161149        65138  -59.58%
BenchmarkTCP6PersistentTimeout-2       152276        44548  -70.75%

R=golang-dev, dave, bradfitz, dvyukov, rsc
CC=golang-dev
https://golang.org/cl/7820045

5 files changed, 70 insertions, 4 deletions

diff --git a/src/pkg/runtime/defs_linux_arm.h b/src/pkg/runtime/defs_linux_arm.h
index 82442b23e0..92160966e1 100644
--- a/src/pkg/runtime/defs_linux_arm.h
+++ b/src/pkg/runtime/defs_linux_arm.h
@@ -2,6 +2,7 @@
 
 // Constants
 enum {
+	EINTR  = 0x4,
 	ENOMEM = 0xc,
 	EAGAIN = 0xb,
 
@@ -65,6 +66,17 @@ enum {
 	ITIMER_VIRTUAL = 0x1,
 	O_RDONLY = 0,
 	O_CLOEXEC = 02000000,
+
+	EPOLLIN		= 0x1,
+	EPOLLOUT	= 0x4,
+	EPOLLERR	= 0x8,
+	EPOLLHUP	= 0x10,
+	EPOLLRDHUP	= 0x2000,
+	EPOLLET		= -0x80000000,
+	EPOLL_CLOEXEC	= 0x80000,
+	EPOLL_CTL_ADD	= 0x1,
+	EPOLL_CTL_DEL	= 0x2,
+	EPOLL_CTL_MOD	= 0x3,
 };
 
 // Types
@@ -146,4 +158,11 @@ struct Sigaction {
 	void *sa_restorer;
 	uint64 sa_mask;
 };
+
+typedef struct EpollEvent EpollEvent;
+struct EpollEvent {
+	uint32	events;
+	uint32	_pad;
+	uint64	data;
+};
 #pragma pack off
diff --git a/src/pkg/runtime/netpoll.goc b/src/pkg/runtime/netpoll.goc
index 152fa174e9..b314c65338 100644
--- a/src/pkg/runtime/netpoll.goc
+++ b/src/pkg/runtime/netpoll.goc
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build darwin linux,386 linux,amd64
+// +build darwin linux
 
 package net
 
diff --git a/src/pkg/runtime/netpoll_epoll.c b/src/pkg/runtime/netpoll_epoll.c
index 53916e1d2e..34ed78addb 100644
--- a/src/pkg/runtime/netpoll_epoll.c
+++ b/src/pkg/runtime/netpoll_epoll.c
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build linux,386 linux,amd64
+// +build linux
 
 #include "runtime.h"
 #include "defs_GOOS_GOARCH.h"
diff --git a/src/pkg/runtime/netpoll_stub.c b/src/pkg/runtime/netpoll_stub.c
index a70b2f772f..39d19a4cea 100644
--- a/src/pkg/runtime/netpoll_stub.c
+++ b/src/pkg/runtime/netpoll_stub.c
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build freebsd linux,arm netbsd openbsd plan9 windows
+// +build freebsd netbsd openbsd plan9 windows
 
 #include "runtime.h"
 
diff --git a/src/pkg/runtime/sys_linux_arm.s b/src/pkg/runtime/sys_linux_arm.s
index e3994bccaa..7f813482d1 100644
--- a/src/pkg/runtime/sys_linux_arm.s
+++ b/src/pkg/runtime/sys_linux_arm.s
@@ -36,6 +36,11 @@
 #define SYS_ugetrlimit (SYS_BASE + 191)
 #define SYS_sched_getaffinity (SYS_BASE + 242)
 #define SYS_clock_gettime (SYS_BASE + 263)
+#define SYS_epoll_create (SYS_BASE + 250)
+#define SYS_epoll_ctl (SYS_BASE + 251)
+#define SYS_epoll_wait (SYS_BASE + 252)
+#define SYS_epoll_create1 (SYS_BASE + 357)
+#define SYS_fcntl (SYS_BASE + 55)
 
 #define ARM_BASE (SYS_BASE + 0x0f0000)
 
@@ -371,7 +376,6 @@ cascheck:
 	MOVW $0, R0
 	RET
 
-
 TEXT runtime·casp(SB),7,$0
 	B	runtime·cas(SB)
 
@@ -387,3 +391,46 @@ TEXT runtime·sched_getaffinity(SB),7,$0
 	MOVW	$SYS_sched_getaffinity, R7
 	SWI	$0
 	RET
+
+// int32 runtime·epollcreate(int32 size)
+TEXT runtime·epollcreate(SB),7,$0
+	MOVW	0(FP), R0
+	MOVW	$SYS_epoll_create, R7
+	SWI	$0
+	RET
+
+// int32 runtime·epollcreate1(int32 flags)
+TEXT runtime·epollcreate1(SB),7,$0
+	MOVW	0(FP), R0
+	MOVW	$SYS_epoll_create1, R7
+	SWI	$0
+	RET
+
+// int32 runtime·epollctl(int32 epfd, int32 op, int32 fd, EpollEvent *ev)
+TEXT runtime·epollctl(SB),7,$0
+	MOVW	0(FP), R0
+	MOVW	4(FP), R1
+	MOVW	8(FP), R2
+	MOVW	12(FP), R3
+	MOVW	$SYS_epoll_ctl, R7
+	SWI	$0
+	RET
+
+// int32 runtime·epollwait(int32 epfd, EpollEvent *ev, int32 nev, int32 timeout)
+TEXT runtime·epollwait(SB),7,$0
+	MOVW	0(FP), R0
+	MOVW	4(FP), R1
+	MOVW	8(FP), R2
+	MOVW	12(FP), R3
+	MOVW	$SYS_epoll_wait, R7
+	SWI	$0
+	RET
+
+// void runtime·closeonexec(int32 fd)
+TEXT runtime·closeonexec(SB),7,$0
+	MOVW	0(FP), R0	// fd
+	MOVW	$2, R1	// F_SETFD
+	MOVW	$1, R2	// FD_CLOEXEC
+	MOVW	$SYS_fcntl, R7
+	SWI $0
+	RET