Can SRTO_CONNTIMEO accurately set the timeout of srt_connect?

[KevinChau9527]

Ver : v1.5.0

I tried setting the timeout for srt_connect to reduce the connection wait, the pseudo code like:

    int connection_timeout_ms = 600;
    srt_setsockopt(ss, 0, SRTO_CONNTIMEO, &connection_timeout_ms, sizeof connection_timeout_ms);

    while (1) {
        const std::chrono::steady_clock::time_point chrono_ts_start = std::chrono::steady_clock::now();
        st = srt_connect(ss, (struct sockaddr *) &sa, sizeof sa);
        if (st == SRT_ERROR) {
            const std::chrono::steady_clock::time_point chrono_ts_end = std::chrono::steady_clock::now();
            const auto delta_ms = std::chrono::duration_cast<std::chrono::milliseconds>(chrono_ts_end - chrono_ts_start).count();
            fprintf(stderr, "srt_connect: %s, timeout :%llu\n", srt_getlasterror_str(), delta_ms);

            connection_timeout_ms += 100;
            fprintf(stderr, "reset timeout to %d ms\n", connection_timeout_ms);
            srt_setsockopt(ss, 0, SRTO_CONNTIMEO, &connection_timeout_ms, sizeof connection_timeout_ms);

        } else {
            printf("srt connect ok\n");
            break;
        }
    }

However, from the output, the actual timeout period seem to increase in steps of 1000ms.

srt_connect: Connection setup failure: connection timed out, timeout :1009
reset timeout to 800 ms
srt_connect: Connection setup failure: connection timed out, timeout :1010
reset timeout to 1000 ms
srt_connect: Connection setup failure: connection timed out, timeout :1012
reset timeout to 1200 ms
srt_connect: Connection setup failure: connection timed out, timeout :2020
reset timeout to 1400 ms
srt_connect: Connection setup failure: connection timed out, timeout :2013
reset timeout to 1600 ms
srt_connect: Connection setup failure: connection timed out, timeout :2016
reset timeout to 1800 ms
srt_connect: Connection setup failure: connection timed out, timeout :2017
reset timeout to 2000 ms
srt_connect: Connection setup failure: connection timed out, timeout :2019
reset timeout to 2200 ms
srt_connect: Connection setup failure: connection timed out, timeout :3021
reset timeout to 2400 ms
srt_connect: Connection setup failure: connection timed out, timeout :3022
reset timeout to 2600 ms
srt_connect: Connection setup failure: connection timed out, timeout :3034
reset timeout to 2800 ms

Is this result in line with expectations? Is there any relevant API or method to set a precise connection timeout?

[maxsharabayko]

There is a connection timeout unit test: test_connection_timeout.cpp. The observed accuracy is +/- 200 ms.

[KevinChau9527]

I set the timeout of test_connection_timeout to 400ms and ran the unit test BlockingLoop. The result showed that it was not executed according to the preset value. Here is the output:

kevin@kevin-machine:~/srt-1.5.0/build$ ./test-srt --gtest_filter=TestConnectionTimeout.BlockingLoop
Running main() from /home/kevin/srt-1.5.0/build/googletest/googletest-src/googletest/src/gtest_main.cc
Note: Google Test filter = TestConnectionTimeout.BlockingLoop
[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from TestConnectionTimeout
[ RUN      ] TestConnectionTimeout.BlockingLoop
Running test on port 5000
connection_timeout_ms is set [400ms]
/home/kevin/srt-1.5.0/test/test_connection_timeout.cpp:192: Failure
Expected: (delta_ms) <= (connection_timeout_ms + 200), actual: 1000 vs 600
/home/kevin/srt-1.5.0/test/test_connection_timeout.cpp:192: Failure
Expected: (delta_ms) <= (connection_timeout_ms + 200), actual: 1000 vs 600
/home/kevin/srt-1.5.0/test/test_connection_timeout.cpp:192: Failure
Expected: (delta_ms) <= (connection_timeout_ms + 200), actual: 1000 vs 600
/home/kevin/srt-1.5.0/test/test_connection_timeout.cpp:192: Failure
Expected: (delta_ms) <= (connection_timeout_ms + 200), actual: 1000 vs 600
/home/kevin/srt-1.5.0/test/test_connection_timeout.cpp:192: Failure
Expected: (delta_ms) <= (connection_timeout_ms + 200), actual: 1000 vs 600
/home/kevin/srt-1.5.0/test/test_connection_timeout.cpp:192: Failure
Expected: (delta_ms) <= (connection_timeout_ms + 200), actual: 1000 vs 600
/home/kevin/srt-1.5.0/test/test_connection_timeout.cpp:192: Failure
Expected: (delta_ms) <= (connection_timeout_ms + 200), actual: 1000 vs 600
/home/kevin/srt-1.5.0/test/test_connection_timeout.cpp:192: Failure
Expected: (delta_ms) <= (connection_timeout_ms + 200), actual: 1000 vs 600
/home/kevin/srt-1.5.0/test/test_connection_timeout.cpp:192: Failure
Expected: (delta_ms) <= (connection_timeout_ms + 200), actual: 1000 vs 600
/home/kevin/srt-1.5.0/test/test_connection_timeout.cpp:192: Failure
Expected: (delta_ms) <= (connection_timeout_ms + 200), actual: 1000 vs 600
[  FAILED  ] TestConnectionTimeout.BlockingLoop (10012 ms)
[----------] 1 test from TestConnectionTimeout (10012 ms total)

[----------] Global test environment tear-down
[==========] 1 test from 1 test case ran. (10013 ms total)
[  PASSED  ] 0 tests.
[  FAILED  ] 1 test, listed below:
[  FAILED  ] TestConnectionTimeout.BlockingLoop

 1 FAILED TEST

[maxsharabayko]

What is you hardware platform and your build configuration of SRT?

[KevinChau9527]

What is you hardware platform and your build configuration of SRT?

Host: Ubuntu 22.04 with 6.5.0-44-generic kernel
build configuraion: -DENABLE_STDCXX_SYNC=ON -DENABLE_UNITTESTS=ON -DENABLE_TESTING=ON

[KevinChau9527]

What is you hardware platform and your build configuration of SRT?

Hi @maxsharabayko, Is there any progress on this issue?

[maxsharabayko]

Please share your hardware specification. Is it maybe a VM?