runtime: add network polling support into scheduler
This is a part of the bigger change that moves network poller into runtime:
https://golang.org/cl/7326051/
R=golang-dev, bradfitz, mikioh.mikioh, rsc
CC=golang-dev
https://golang.org/cl/7448048
diff --git a/src/pkg/runtime/netpoll_stub.c b/src/pkg/runtime/netpoll_stub.c
new file mode 100644
index 0000000..90da7a8
--- /dev/null
+++ b/src/pkg/runtime/netpoll_stub.c
@@ -0,0 +1,18 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build windows
+
+#include "runtime.h"
+
+// Polls for ready network connections.
+// Returns list of goroutines that become runnable.
+G*
+runtime·netpoll(bool block)
+{
+ // Implementation for platforms that do not support
+ // integrated network poller.
+ USED(block);
+ return nil;
+}
diff --git a/src/pkg/runtime/proc.c b/src/pkg/runtime/proc.c
index fff270c..313ac65 100644
--- a/src/pkg/runtime/proc.c
+++ b/src/pkg/runtime/proc.c
@@ -49,6 +49,7 @@
Note stopnote;
uint32 sysmonwait;
Note sysmonnote;
+ uint64 lastpoll;
int32 profilehz; // cpu profiling rate
};
@@ -107,6 +108,7 @@
static G* globrunqget(P*);
static P* pidleget(void);
static void pidleput(P*);
+static void injectglist(G*);
// The bootstrap sequence is:
//
@@ -135,6 +137,7 @@
// so that we don't need to call malloc when we crash.
// runtime·findfunc(0);
+ runtime·sched.lastpoll = runtime·nanotime();
procs = 1;
p = runtime·getenv("GOMAXPROCS");
if(p != nil && (n = runtime·atoi(p)) > 0) {
@@ -391,8 +394,11 @@
{
P *p, *p1;
M *mp;
+ G *gp;
bool add;
+ gp = runtime·netpoll(false); // non-blocking
+ injectglist(gp);
add = needaddgcproc();
runtime·lock(&runtime·sched);
if(newprocs) {
@@ -976,7 +982,7 @@
}
// Finds a runnable goroutine to execute.
-// Tries to steal from other P's and get g from global queue.
+// Tries to steal from other P's, get g from global queue, poll network.
static G*
findrunnable(void)
{
@@ -1001,6 +1007,13 @@
if(gp)
return gp;
}
+ // poll network
+ gp = runtime·netpoll(false); // non-blocking
+ if(gp) {
+ injectglist(gp->schedlink);
+ gp->status = Grunnable;
+ return gp;
+ }
// If number of spinning M's >= number of busy P's, block.
// This is necessary to prevent excessive CPU consumption
// when GOMAXPROCS>>1 but the program parallelism is low.
@@ -1055,10 +1068,54 @@
break;
}
}
+ // poll network
+ if(runtime·xchg64(&runtime·sched.lastpoll, 0) != 0) {
+ if(m->p)
+ runtime·throw("findrunnable: netpoll with p");
+ if(m->spinning)
+ runtime·throw("findrunnable: netpoll with spinning");
+ gp = runtime·netpoll(true); // block until new work is available
+ runtime·atomicstore64(&runtime·sched.lastpoll, runtime·nanotime());
+ if(gp) {
+ runtime·lock(&runtime·sched);
+ p = pidleget();
+ runtime·unlock(&runtime·sched);
+ if(p) {
+ acquirep(p);
+ injectglist(gp->schedlink);
+ gp->status = Grunnable;
+ return gp;
+ }
+ injectglist(gp);
+ }
+ }
stopm();
goto top;
}
+// Injects the list of runnable G's into the scheduler.
+// Can run concurrently with GC.
+static void
+injectglist(G *glist)
+{
+ int32 n;
+ G *gp;
+
+ if(glist == nil)
+ return;
+ runtime·lock(&runtime·sched);
+ for(n = 0; glist; n++) {
+ gp = glist;
+ glist = gp->schedlink;
+ gp->status = Grunnable;
+ globrunqput(gp);
+ }
+ runtime·unlock(&runtime·sched);
+
+ for(; n && runtime·sched.npidle; n--)
+ startm(nil, false);
+}
+
// One round of scheduler: find a runnable goroutine and execute it.
// Never returns.
static void
@@ -1916,6 +1973,8 @@
sysmon(void)
{
uint32 idle, delay;
+ int64 now, lastpoll;
+ G *gp;
uint32 ticks[MaxGomaxprocs];
idle = 0; // how many cycles in succession we had not wokeup somebody
@@ -1940,6 +1999,14 @@
} else
runtime·unlock(&runtime·sched);
}
+ // poll network if not polled for more than 10ms
+ lastpoll = runtime·atomicload64(&runtime·sched.lastpoll);
+ now = runtime·nanotime();
+ if(lastpoll != 0 && lastpoll + 10*1000*1000 > now) {
+ gp = runtime·netpoll(false); // non-blocking
+ injectglist(gp);
+ }
+ // retake P's blocked in syscalls
if(retake(ticks))
idle = 0;
else
diff --git a/src/pkg/runtime/runtime.h b/src/pkg/runtime/runtime.h
index b027607..ffbd5c2 100644
--- a/src/pkg/runtime/runtime.h
+++ b/src/pkg/runtime/runtime.h
@@ -767,6 +767,7 @@
extern int64 runtime·blockprofilerate;
void runtime·addtimer(Timer*);
bool runtime·deltimer(Timer*);
+G* runtime·netpoll(bool);
#pragma varargck argpos runtime·printf 1
#pragma varargck type "d" int32
@@ -968,5 +969,5 @@
enum
{
- UseSpanType = 1,
+ UseSpanType = 0,
};
