[Spice-devel] [PATCH 1/3] red_worker: decrease the timeout when flushing commands and waiting for the client.

[Yonit Halperin]

150 seconds is way too long period for holding the guest driver and
waiting for a response for the client. This timeout was 15 seconds, but
when off-screen surfaces ware introduced it was arbitrarily multiplied by
10.
Other existing related bugs emphasize why it is important to decrease
the timeout:
(1) 994211 - the qxl driver waits for an async-io reponse for 60 seconds
    and after that, it switches to sync-io mode. Not only that the
    driver might use invalid data (since it didn't wait for the query to
    complete), falling back to sync-io mode introduces other errors.
(2) 994175 - spice server sometimes doesn't recognize that the client
             has disconnected.
(3) There might be cache inconsistency between the client and the server,
and then the display channel waits indefinitely for a cache item (e.g., bug
977998)

This patch changes the timeout to 30 seconds. I tested it under wifi +emulating 2.5Mbps network,
together with playing video on the guest and changing resolutions in a loop. The timeout didn't expired
during my tests.

This bug is related to rhbz#964136 (but from rhbz#964136 info it is still not
clear why the client wasn't responsive).
---
 server/red_worker.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/server/red_worker.c b/server/red_worker.c
index b45208b..9896696 100644
--- a/server/red_worker.c
+++ b/server/red_worker.c
@@ -103,7 +103,7 @@
 #define CHANNEL_PUSH_TIMEOUT 30000000000ULL //nano
 #define CHANNEL_PUSH_SLEEP_DURATION 10000 //micro
 
-#define DISPLAY_CLIENT_TIMEOUT 15000000000ULL //nano
+#define DISPLAY_CLIENT_TIMEOUT 30000000000ULL //nano
 #define DISPLAY_CLIENT_MIGRATE_DATA_TIMEOUT 10000000000ULL //nano, 10 sec
 #define DISPLAY_CLIENT_RETRY_INTERVAL 10000 //micro
 
@@ -9716,7 +9716,7 @@ static inline void flush_display_commands(RedWorker *worker)
         if (ring_is_empty) {
             break;
         }
-        end_time = red_now() + DISPLAY_CLIENT_TIMEOUT * 10;
+        end_time = red_now() + DISPLAY_CLIENT_TIMEOUT;
         int sleep_count = 0;
         for (;;) {
             red_channel_push(&worker->display_channel->common.base);
@@ -9760,7 +9760,7 @@ static inline void flush_cursor_commands(RedWorker *worker)
         if (ring_is_empty) {
             break;
         }
-        end_time = red_now() + DISPLAY_CLIENT_TIMEOUT * 10;
+        end_time = red_now() + DISPLAY_CLIENT_TIMEOUT;
         int sleep_count = 0;
         for (;;) {
             red_channel_push(&worker->cursor_channel->common.base);
-- 
1.8.1.4