net: spread fd over several pollservers.
Lighten contention without preventing further improvements on pollservers.
Connections are spread over Min(GOMAXPROCS, NumCPU, 8) pollserver instances.
Median of 10 runs, 4 cores @ 3.4GHz, amd/linux-3.2:
BenchmarkTCPOneShot 171917 ns/op 175194 ns/op 1.91%
BenchmarkTCPOneShot-2 101413 ns/op 109462 ns/op 7.94%
BenchmarkTCPOneShot-4 91796 ns/op 35712 ns/op -61.10%
BenchmarkTCPOneShot-6 90938 ns/op 30607 ns/op -66.34%
BenchmarkTCPOneShot-8 90374 ns/op 29150 ns/op -67.75%
BenchmarkTCPOneShot-16 101089 ns/op 111526 ns/op 10.32%
BenchmarkTCPOneShotTimeout 174986 ns/op 178606 ns/op 2.07%
BenchmarkTCPOneShotTimeout-2 101585 ns/op 110678 ns/op 8.95%
BenchmarkTCPOneShotTimeout-4 91547 ns/op 35931 ns/op -60.75%
BenchmarkTCPOneShotTimeout-6 91496 ns/op 31019 ns/op -66.10%
BenchmarkTCPOneShotTimeout-8 90670 ns/op 29531 ns/op -67.43%
BenchmarkTCPOneShotTimeout-16 101013 ns/op 106026 ns/op 4.96%
BenchmarkTCPPersistent 51731 ns/op 53324 ns/op 3.08%
BenchmarkTCPPersistent-2 32888 ns/op 30678 ns/op -6.72%
BenchmarkTCPPersistent-4 25751 ns/op 15595 ns/op -39.44%
BenchmarkTCPPersistent-6 26737 ns/op 9805 ns/op -63.33%
BenchmarkTCPPersistent-8 26850 ns/op 9730 ns/op -63.76%
BenchmarkTCPPersistent-16 104449 ns/op 102838 ns/op -1.54%
BenchmarkTCPPersistentTimeout 51806 ns/op 53281 ns/op 2.85%
BenchmarkTCPPersistentTimeout-2 32956 ns/op 30895 ns/op -6.25%
BenchmarkTCPPersistentTimeout-4 25994 ns/op 18111 ns/op -30.33%
BenchmarkTCPPersistentTimeout-6 26679 ns/op 9846 ns/op -63.09%
BenchmarkTCPPersistentTimeout-8 26810 ns/op 9727 ns/op -63.72%
BenchmarkTCPPersistentTimeout-16 101652 ns/op 104410 ns/op 2.71%
R=rsc, dvyukov, dave, mikioh.mikioh, bradfitz, remyoudompheng
CC=golang-dev
https://golang.org/cl/6496054
diff --git a/src/pkg/net/fd_unix.go b/src/pkg/net/fd_unix.go
index 57e04bb..c55f336 100644
--- a/src/pkg/net/fd_unix.go
+++ b/src/pkg/net/fd_unix.go
@@ -10,6 +10,7 @@
"errors"
"io"
"os"
+ "runtime"
"sync"
"syscall"
"time"
@@ -45,6 +46,9 @@
// owned by fd wait server
ncr, ncw int
+
+ // wait server
+ pollServer *pollServer
}
// A pollServer helps FDs determine when to retry a non-blocking
@@ -255,21 +259,45 @@
}
// Network FD methods.
-// All the network FDs use a single pollServer.
+// Spread network FDs over several pollServers.
-var pollserver *pollServer
-var onceStartServer sync.Once
+var pollMaxN int
+var pollservers []*pollServer
+var startServersOnce []func()
-func startServer() {
+func init() {
+ pollMaxN = runtime.NumCPU()
+ if pollMaxN > 8 {
+ pollMaxN = 8 // No improvement then.
+ }
+ pollservers = make([]*pollServer, pollMaxN)
+ startServersOnce = make([]func(), pollMaxN)
+ for i := 0; i < pollMaxN; i++ {
+ k := i
+ once := new(sync.Once)
+ startServersOnce[i] = func() { once.Do(func() { startServer(k) }) }
+ }
+}
+
+func startServer(k int) {
p, err := newPollServer()
if err != nil {
- print("Start pollServer: ", err.Error(), "\n")
+ panic(err)
}
- pollserver = p
+ pollservers[k] = p
+}
+
+func server(fd int) *pollServer {
+ pollN := runtime.GOMAXPROCS(0)
+ if pollN > pollMaxN {
+ pollN = pollMaxN
+ }
+ k := fd % pollN
+ startServersOnce[k]()
+ return pollservers[k]
}
func newFD(fd, family, sotype int, net string) (*netFD, error) {
- onceStartServer.Do(startServer)
if err := syscall.SetNonblock(fd, true); err != nil {
return nil, err
}
@@ -281,6 +309,7 @@
}
netfd.cr = make(chan error, 1)
netfd.cw = make(chan error, 1)
+ netfd.pollServer = server(fd)
return netfd, nil
}
@@ -300,7 +329,7 @@
func (fd *netFD) connect(ra syscall.Sockaddr) error {
err := syscall.Connect(fd.sysfd, ra)
if err == syscall.EINPROGRESS {
- if err = pollserver.WaitWrite(fd); err != nil {
+ if err = fd.pollServer.WaitWrite(fd); err != nil {
return err
}
var e int
@@ -354,8 +383,8 @@
}
func (fd *netFD) Close() error {
- pollserver.Lock() // needed for both fd.incref(true) and pollserver.Evict
- defer pollserver.Unlock()
+ fd.pollServer.Lock() // needed for both fd.incref(true) and pollserver.Evict
+ defer fd.pollServer.Unlock()
if err := fd.incref(true); err != nil {
return err
}
@@ -364,7 +393,7 @@
// the final decref will close fd.sysfd. This should happen
// fairly quickly, since all the I/O is non-blocking, and any
// attempts to block in the pollserver will return errClosing.
- pollserver.Evict(fd)
+ fd.pollServer.Evict(fd)
fd.decref()
return nil
}
@@ -401,7 +430,7 @@
if err == syscall.EAGAIN {
err = errTimeout
if fd.rdeadline >= 0 {
- if err = pollserver.WaitRead(fd); err == nil {
+ if err = fd.pollServer.WaitRead(fd); err == nil {
continue
}
}
@@ -431,7 +460,7 @@
if err == syscall.EAGAIN {
err = errTimeout
if fd.rdeadline >= 0 {
- if err = pollserver.WaitRead(fd); err == nil {
+ if err = fd.pollServer.WaitRead(fd); err == nil {
continue
}
}
@@ -459,7 +488,7 @@
if err == syscall.EAGAIN {
err = errTimeout
if fd.rdeadline >= 0 {
- if err = pollserver.WaitRead(fd); err == nil {
+ if err = fd.pollServer.WaitRead(fd); err == nil {
continue
}
}
@@ -501,7 +530,7 @@
if err == syscall.EAGAIN {
err = errTimeout
if fd.wdeadline >= 0 {
- if err = pollserver.WaitWrite(fd); err == nil {
+ if err = fd.pollServer.WaitWrite(fd); err == nil {
continue
}
}
@@ -533,7 +562,7 @@
if err == syscall.EAGAIN {
err = errTimeout
if fd.wdeadline >= 0 {
- if err = pollserver.WaitWrite(fd); err == nil {
+ if err = fd.pollServer.WaitWrite(fd); err == nil {
continue
}
}
@@ -560,7 +589,7 @@
if err == syscall.EAGAIN {
err = errTimeout
if fd.wdeadline >= 0 {
- if err = pollserver.WaitWrite(fd); err == nil {
+ if err = fd.pollServer.WaitWrite(fd); err == nil {
continue
}
}
@@ -595,7 +624,7 @@
if err == syscall.EAGAIN {
err = errTimeout
if fd.rdeadline >= 0 {
- if err = pollserver.WaitRead(fd); err == nil {
+ if err = fd.pollServer.WaitRead(fd); err == nil {
continue
}
}
