This patch by Tony Reix improves the AIX netpoll code used by libgo.
Bootstrapped on x86_64-pc-linux-gnu. Committed to mainline.
Ian
Index: gcc/go/gofrontend/MERGE
===================================================================
--- gcc/go/gofrontend/MERGE (revision 251127)
+++ gcc/go/gofrontend/MERGE (working copy)
@@ -1,4 +1,4 @@
-f02183eb66f5718769f3f6541dcc6744ae1771c0
+152164a7249ecc5c2bfd4a091450dc7c2855f609
The first line of this file holds the git revision number of the last
merge done from the gofrontend repository.
Index: libgo/go/runtime/netpoll_aix.go
===================================================================
--- libgo/go/runtime/netpoll_aix.go (revision 250873)
+++ libgo/go/runtime/netpoll_aix.go (working copy)
@@ -7,10 +7,10 @@ package runtime
import "unsafe"
// This is based on the former libgo/runtime/netpoll_select.c implementation
-// except that it uses poll instead of select and is written in Go.
+// except that it uses AIX pollset_poll instead of select and is written in Go.
+
+type pollset_t int32
-// These definitions should come from sysinfo.go as they may be OS-dependent.
-// These are the definitions for the AIX operating system.
type pollfd struct {
fd int32
events int16
@@ -22,8 +22,23 @@ const _POLLOUT = 0x0002
const _POLLHUP = 0x2000
const _POLLERR = 0x4000
-//extern poll
-func libc_poll(pfds *pollfd, npfds uintptr, timeout uintptr) int32
+type poll_ctl struct {
+ cmd int16
+ events int16
+ fd int32
+}
+
+const _PS_ADD = 0x0
+const _PS_DELETE = 0x2
+
+//extern pollset_create
+func pollset_create(maxfd int32) pollset_t
+
+//extern pollset_ctl
+func pollset_ctl(ps pollset_t, pollctl_array *poll_ctl, array_length int32)
int32
+
+//extern pollset_poll
+func pollset_poll(ps pollset_t, polldata_array *pollfd, array_length int32,
timeout int32) int32
//extern pipe
func libc_pipe(fd *int32) int32
@@ -31,60 +46,100 @@ func libc_pipe(fd *int32) int32
//extern __go_fcntl_uintptr
func fcntlUintptr(fd, cmd, arg uintptr) (uintptr, uintptr)
-func closeonexec(fd int32) {
- fcntlUintptr(uintptr(fd), _F_SETFD, _FD_CLOEXEC)
+func fcntl(fd, cmd int32, arg uintptr) uintptr {
+ r, _ := fcntlUintptr(uintptr(fd), uintptr(cmd), arg)
+ return r
}
var (
- allocated int
- pfds []pollfd
- mpfds map[uintptr]*pollDesc
- pmtx mutex
- rdwake int32
- wrwake int32
+ ps pollset_t = -1
+ mpfds map[int32]*pollDesc
+ pmtx mutex
+ rdwake int32
+ wrwake int32
+ needsUpdate bool
)
func netpollinit() {
var p [2]int32
- // Create the pipe we use to wakeup poll.
+ if ps = pollset_create(-1); ps < 0 {
+ throw("netpollinit: failed to create pollset")
+ }
+ // It is not possible to add or remove descriptors from
+ // the pollset while pollset_poll is active.
+ // We use a pipe to wakeup pollset_poll when the pollset
+ // needs to be updated.
if err := libc_pipe(&p[0]); err < 0 {
throw("netpollinit: failed to create pipe")
}
rdwake = p[0]
wrwake = p[1]
- closeonexec(rdwake)
- closeonexec(wrwake)
-
- // Pre-allocate array of pollfd structures for poll.
- allocated = 128
- pfds = make([]pollfd, allocated)
+ fl := fcntl(rdwake, _F_GETFL, 0)
+ fcntl(rdwake, _F_SETFL, fl|_O_NONBLOCK)
+ fcntl(rdwake, _F_SETFD, _FD_CLOEXEC)
+
+ fl = fcntl(wrwake, _F_GETFL, 0)
+ fcntl(wrwake, _F_SETFL, fl|_O_NONBLOCK)
+ fcntl(wrwake, _F_SETFD, _FD_CLOEXEC)
+
+ // Add the read side of the pipe to the pollset.
+ var pctl poll_ctl
+ pctl.cmd = _PS_ADD
+ pctl.fd = rdwake
+ pctl.events = _POLLIN
+ if pollset_ctl(ps, &pctl, 1) != 0 {
+ throw("netpollinit: failed to register pipe")
+ }
- mpfds = make(map[uintptr]*pollDesc)
+ mpfds = make(map[int32]*pollDesc)
}
func netpollopen(fd uintptr, pd *pollDesc) int32 {
+ // pollset_ctl will block if pollset_poll is active
+ // so wakeup pollset_poll first.
lock(&pmtx)
- mpfds[fd] = pd
+ needsUpdate = true
unlock(&pmtx)
-
- // Wakeup poll.
b := [1]byte{0}
write(uintptr(wrwake), unsafe.Pointer(&b[0]), 1)
+ var pctl poll_ctl
+ pctl.cmd = _PS_ADD
+ pctl.fd = int32(fd)
+ pctl.events = _POLLIN | _POLLOUT
+ if pollset_ctl(ps, &pctl, 1) != 0 {
+ return int32(errno())
+ }
+ lock(&pmtx)
+ mpfds[int32(fd)] = pd
+ needsUpdate = false
+ unlock(&pmtx)
+
return 0
}
func netpollclose(fd uintptr) int32 {
+ // pollset_ctl will block if pollset_poll is active
+ // so wakeup pollset_poll first.
lock(&pmtx)
- delete(mpfds, fd)
+ needsUpdate = true
unlock(&pmtx)
-
- // Wakeup poll.
b := [1]byte{0}
write(uintptr(wrwake), unsafe.Pointer(&b[0]), 1)
+ var pctl poll_ctl
+ pctl.cmd = _PS_DELETE
+ pctl.fd = int32(fd)
+ if pollset_ctl(ps, &pctl, 1) != 0 {
+ return int32(errno())
+ }
+ lock(&pmtx)
+ delete(mpfds, int32(fd))
+ needsUpdate = false
+ unlock(&pmtx)
+
return 0
}
@@ -93,62 +148,39 @@ func netpollarm(pd *pollDesc, mode int)
}
func netpoll(block bool) *g {
- if allocated == 0 {
+ if ps == -1 {
return nil
}
- timeout := ^uintptr(0)
+ timeout := int32(-1)
if !block {
timeout = 0
}
+ var pfds [128]pollfd
retry:
lock(&pmtx)
- npfds := len(mpfds) + 1
- unlock(&pmtx)
-
- if npfds > allocated {
- for npfds > allocated {
- allocated *= 2
- }
- pfds = make([]pollfd, allocated)
- }
-
- // Poll the read side of the pipe.
- pfds[0].fd = rdwake
- pfds[0].events = _POLLIN
- lock(&pmtx)
- // Notice that npfds may have changed since we released the lock.
- // Just copy what we can, new descriptors will be added at next
- // iteration.
- i := 1
- for fd := range mpfds {
- if i >= allocated {
- break
- }
- pfds[i].fd = int32(fd)
- pfds[i].events = _POLLIN | _POLLOUT
- i++
+ if needsUpdate {
+ unlock(&pmtx)
+ osyield()
+ goto retry
}
- npfds = i
unlock(&pmtx)
-
- n := libc_poll(&pfds[0], uintptr(npfds), timeout)
- if n < 0 {
+ nfound := pollset_poll(ps, &pfds[0], int32(len(pfds)), timeout)
+ if nfound < 0 {
e := errno()
if e != _EINTR {
- throw("poll failed")
+ throw("pollset_poll failed")
}
goto retry
}
var gp guintptr
- for i = 0; i < npfds && n > 0; i++ {
- pfd := pfds[i]
+ for i := int32(0); i < nfound; i++ {
+ pfd := &pfds[i]
var mode int32
if pfd.revents&(_POLLIN|_POLLHUP|_POLLERR) != 0 {
- if i == 0 {
+ if pfd.fd == rdwake {
var b [1]byte
read(pfd.fd, unsafe.Pointer(&b[0]), 1)
- n--
continue
}
mode += 'r'
@@ -158,12 +190,11 @@ retry:
}
if mode != 0 {
lock(&pmtx)
- pd := mpfds[uintptr(pfd.fd)]
+ pd := mpfds[pfd.fd]
unlock(&pmtx)
if pd != nil {
netpollready(&gp, pd, mode)
}
- n--
}
}
if block && gp == 0 {
