From: Marc-André Lureau <marcandre.lureau@xxxxxxxxx>
The current coroutine channel_iterate() creates a GSource for the socket
reenters the mainloop waiting for IO condition. This is really heavy
usage of mainloop showing up in system time and user space
profiling (10% of CPU time spent in mainloop overhead). Instead flush
all pending input messages before switching context and reentering main
loop.
This is the kind of results I get with a replay:
before:
2179,440455 task-clock # 0,629 CPUs utilized
3 580 context-switches # 0,002 M/sec
207 cpu-migrations # 0,095 K/sec
48 909 page-faults # 0,022 M/sec
7 362 442 301 cycles # 3,378 GHz
5 256 957 520 stalled-cycles-frontend # 71,40% frontend cycles
idle
<not supported> stalled-cycles-backend
5 460 266 981 instructions # 0,74 insns per cycle
# 0,96 stalled cycles
per insn
982 749 523 branches # 450,918 M/sec
20 745 453 branch-misses # 2,11% of all branches
3,463422087 seconds time elapsed
after:
1741,651383 task-clock # 0,522 CPUs utilized
5 093 context-switches # 0,003 M/sec
137 cpu-migrations # 0,079 K/sec
49 033 page-faults # 0,028 M/sec
5 874 567 974 cycles # 3,373 GHz
4 247 059 288 stalled-cycles-frontend # 72,30% frontend cycles
idle
<not supported> stalled-cycles-backend
4 419 666 346 instructions # 0,75 insns per cycle
# 0,96 stalled cycles
per insn
776 972 366 branches # 446,112 M/sec
17 862 170 branch-misses # 2,30% of all branches
3,337472053 seconds time elapsed
---
gtk/spice-channel.c | 59 +++++++++++++++++++++++++----------------------------
1 file changed, 28 insertions(+), 31 deletions(-)
diff --git a/gtk/spice-channel.c b/gtk/spice-channel.c
index 55c8325..f6a691e 100644
--- a/gtk/spice-channel.c
+++ b/gtk/spice-channel.c
@@ -2080,10 +2080,24 @@ static void spice_channel_iterate_read(SpiceChannel *channel)
{
SpiceChannelPrivate *c = channel->priv;
- g_return_if_fail(c->state != SPICE_CHANNEL_STATE_MIGRATING);
+ g_coroutine_socket_wait(&c->coroutine, c->sock, G_IO_IN);
+
+ /* treat all incoming data (block on message completion) */
+ while (!c->has_error &&
+ c->state != SPICE_CHANNEL_STATE_MIGRATING &&
+ g_socket_condition_check(c->sock, G_IO_IN) & G_IO_IN) {
+
+ do
+ spice_channel_recv_msg(channel,
+ (handler_msg_in)SPICE_CHANNEL_GET_CLASS(channel)->handle_msg, NULL);
+#if HAVE_SASL
+ /* flush the sasl buffer too */
+ while (c->sasl_decoded != NULL);
+#else
+ while (FALSE);
+#endif
+ }
- spice_channel_recv_msg(channel,
- (handler_msg_in)SPICE_CHANNEL_GET_CLASS(channel)->handle_msg, NULL);
}
static gboolean wait_migration(gpointer data)
@@ -2105,37 +2119,20 @@ static gboolean spice_channel_iterate(SpiceChannel *channel)
SpiceChannelPrivate *c = channel->priv;
GIOCondition ret;
- do {
- if (c->state == SPICE_CHANNEL_STATE_MIGRATING &&
- !g_coroutine_condition_wait(&c->coroutine, wait_migration, channel))
- CHANNEL_DEBUG(channel, "migration wait cancelled");
-
- if (c->has_error) {
- CHANNEL_DEBUG(channel, "channel has error, breaking loop");
- return FALSE;
- }
-
- SPICE_CHANNEL_GET_CLASS(channel)->iterate_write(channel);
-
- ret = g_coroutine_socket_wait(&c->coroutine, c->sock,
- c->state != SPICE_CHANNEL_STATE_MIGRATING ? G_IO_IN : 0);
-
-#ifdef WIN32
- /* FIXME: windows gsocket is buggy, it doesn't return correct condition... */
- ret = g_socket_condition_check(c->sock, G_IO_IN);
-#endif
- } while (ret == 0); /* ret == 0 means no IO condition, but woken up */
+ if (c->state == SPICE_CHANNEL_STATE_MIGRATING &&
+ !g_coroutine_condition_wait(&c->coroutine, wait_migration, channel))
+ CHANNEL_DEBUG(channel, "migration wait cancelled");
- if (ret & G_IO_IN) {
- do
- SPICE_CHANNEL_GET_CLASS(channel)->iterate_read(channel);
-#if HAVE_SASL
- while (c->sasl_decoded != NULL);
-#else
- while (FALSE);
-#endif
+ if (c->has_error) {
+ CHANNEL_DEBUG(channel, "channel has error, breaking loop");
+ return FALSE;
}
+ /* flush any pending write and read */
+ SPICE_CHANNEL_GET_CLASS(channel)->iterate_write(channel);
+ SPICE_CHANNEL_GET_CLASS(channel)->iterate_read(channel);
+
+ ret = g_socket_condition_check(c->sock, G_IO_IN | G_IO_ERR | G_IO_HUP);
if (c->state > SPICE_CHANNEL_STATE_CONNECTING &&
ret & (G_IO_ERR|G_IO_HUP)) {
SPICE_DEBUG("got socket error: %d", ret);
--
1.8.3.1
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