fix(websocket): release client-lock during WEBSOCKET_EVENT_DATA #704
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This resolves:
1) Deadlock when trying to reserve a lock in WEBSOCKET_EVENT_DATA,
but lock is held by a thread trying to send a websocket message.
2) High latency caused by writers serialized with WEBSOCKET_EVENT_DATA
while calling esp_websocket_client_send(), even when TCP window
has enough space for the entire message being queued to send.
Multiple writers are still serialized at fragment boundaries, but
only with other writers and websocket error updates.
Fixes espressif#625
| xSemaphoreTakeRecursive(client->lock, lock_timeout); | ||
| esp_websocket_client_abort_connection(client, WEBSOCKET_ERROR_TYPE_TCP_TRANSPORT); | ||
| xSemaphoreGiveRecursive(client->lock); | ||
| break; |
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this break is probably wrong
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Description
Prevent deadlocks when reserving locks in WEBSOCKET_EVENT_DATA handler, and lock is held by another thread sending a websocket message.
Fix high latency caused by writers serialized with WEBSOCKET_EVENT_DATA while calling esp_websocket_client_send(), even when TCP window has enough space for the entire message being queued to send.
Multiple writers are still serialized at fragment boundaries, but only with other writers and websocket error updates.
Related
Fixes #625.
Testing
I tested with a WebSocket echo server running on the same WiFi access point, using the target-example with the following modifications:
vTaskDelay(configTICK_RATE_HZ);to simulate application-processing.Without this patch, the AppMain thread experiences long delays, often either almost 1 second, and sometimes much longer(like 6 seconds) depending on which cores the AppMain and WebSocketClient thread run. The AppMain thread is unable to send at 10Hz, even though the TCP send buffer is never full.
With this patch, the AppMain thread experiences no delays writing websocket frames, and is able to send at 10Hz, as long as the TCP send buffer is not filled.
Examples logs:
test_before_fix.txt
test_before_fix2.txt
test_with_fix.txt
Checklist
Before submitting a Pull Request, please ensure the following: