Re: [PATCH 2/2] tests/qtest: make more migration pre-copy scenarios run non-live

[Fabiano Rosas <farosas@suse.de>]

Daniel P. Berrangé <berrange@redhat.com> writes:

> There are 27 pre-copy live migration scenarios being tested. In all of
> these we force non-convergance and run for one iteration, then let it
> converge and wait for completion during the second (or following)
> iterations. At 3 mbps bandwidth limit the first iteration takes a very
> long time (~30 seconds).
>
> While it is important to test the migration passes and convergance
> logic, it is overkill to do this for all 27 pre-copy scenarios. The
> TLS migration scenarios in particular are merely exercising different
> code paths during connection establishment.
>
> To optimize time taken, switch most of the test scenarios to run
> non-live (ie guest CPUs paused) with no bandwidth limits. This gives
> a massive speed up for most of the test scenarios.
>
> For test coverage the following scenarios are unchanged
>
>  * Precopy with UNIX sockets
>  * Precopy with UNIX sockets and dirty ring tracking
>  * Precopy with XBZRLE
>  * Precopy with multifd
>
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

...

> -        qtest_qmp_eventwait(to, "RESUME");
> +        if (!args->live) {
> +            qtest_qmp_discard_response(to, "{ 'execute' : 'cont'}");
> +        }
> +        if (!got_resume) {
> +            qtest_qmp_eventwait(to, "RESUME");
> +        }

Hi Daniel,

On an aarch64 host I'm sometimes (~30%) seeing a hang here on a TLS test:

../configure --target-list=aarch64-softmmu --enable-gnutls

... ./tests/qtest/migration-test --tap -k -p /aarch64/migration/precopy/tcp/tls/psk/match

(gdb) bt
#0  0x0000fffff7b33f8c in recv () from /lib64/libpthread.so.0
#1  0x0000aaaaaaac8bf4 in recv (__flags=0, __n=1, __buf=0xffffffffe477, __fd=5) at /usr/include/bits/socket2.h:44
#2  qmp_fd_receive (fd=5) at ../tests/qtest/libqmp.c:73
#3  0x0000aaaaaaac6dbc in qtest_qmp_receive_dict (s=0xaaaaaaca7d10) at ../tests/qtest/libqtest.c:713
#4  qtest_qmp_eventwait_ref (s=0xaaaaaaca7d10, event=0xaaaaaab26ce8 "RESUME") at ../tests/qtest/libqtest.c:837
#5  0x0000aaaaaaac6e34 in qtest_qmp_eventwait (s=<optimized out>, event=<optimized out>) at ../tests/qtest/libqtest.c:850
#6  0x0000aaaaaaabbd90 in test_precopy_common (args=0xffffffffe590, args@entry=0xffffffffe5a0) at ../tests/qtest/migration-test.c:1393
#7  0x0000aaaaaaabc804 in test_precopy_tcp_tls_psk_match () at ../tests/qtest/migration-test.c:1564
#8  0x0000fffff7c89630 in ?? () from //usr/lib64/libglib-2.0.so.0
...
#15 0x0000fffff7c89a70 in g_test_run_suite () from //usr/lib64/libglib-2.0.so.0
#16 0x0000fffff7c89ae4 in g_test_run () from //usr/lib64/libglib-2.0.so.0
#17 0x0000aaaaaaab7fdc in main (argc=<optimized out>, argv=<optimized out>) at ../tests/qtest/migration-test.c:2642