[PATCH 0/2] tests/qtest: make migraton-test faster

[Daniel P . Berrangé]

This makes migration-test faster by observing that most of the pre-copy
tests don't need to be doing a live migration. They get sufficient code
coverage with the guest CPUs paused.

On my machine this cuts the overall execution time of migration-test
by 50% from 15 minutes, down to 8 minutes, without sacrificing any
noticeable code coverage.

This is still quite slow though.

The following are the test timings sorted by speed:

/x86_64/migration/auto_converge  68.85
/x86_64/migration/precopy/unix/xbzrle  68.29
/x86_64/migration/postcopy/preempt/tls/psk  36.57
/x86_64/migration/dirty_ring  35.58
/x86_64/migration/precopy/unix/plain  35.56
/x86_64/migration/postcopy/preempt/plain  34.71
/x86_64/migration/postcopy/recovery/plain  34.56
/x86_64/migration/postcopy/tls/psk  34.45
/x86_64/migration/postcopy/preempt/recovery/tls/psk  33.99
/x86_64/migration/postcopy/preempt/recovery/plain  33.99
/x86_64/migration/postcopy/plain  33.78
/x86_64/migration/postcopy/recovery/tls/psk  33.30
/x86_64/migration/multifd/tcp/plain/none  21.12
/x86_64/migration/vcpu_dirty_limit  12.28
/x86_64/migration/multifd/tcp/tls/x509/default-host  2.95
/x86_64/migration/multifd/tcp/tls/x509/allow-anon-client  2.68
/x86_64/migration/multifd/tcp/tls/x509/override-host  2.51
/x86_64/migration/precopy/tcp/tls/x509/default-host  1.52
/x86_64/migration/precopy/unix/tls/x509/override-host  1.49
/x86_64/migration/precopy/unix/tls/psk  1.48
/x86_64/migration/precopy/tcp/tls/psk/match  1.47
/x86_64/migration/multifd/tcp/tls/psk/match  1.35
/x86_64/migration/precopy/tcp/tls/x509/allow-anon-client  1.32
/x86_64/migration/precopy/tcp/tls/x509/override-host  1.27
/x86_64/migration/precopy/tcp/tls/x509/friendly-client  1.27
/x86_64/migration/multifd/tcp/plain/zlib  1.08
/x86_64/migration/precopy/tcp/plain  1.05
/x86_64/migration/fd_proto  1.04
/x86_64/migration/multifd/tcp/tls/psk/mismatch  1.00
/x86_64/migration/multifd/tcp/plain/zstd  0.98
/x86_64/migration/precopy/tcp/tls/x509/hostile-client  0.85
/x86_64/migration/multifd/tcp/tls/x509/mismatch-host  0.79
/x86_64/migration/precopy/tcp/tls/x509/mismatch-host  0.75
/x86_64/migration/precopy/unix/tls/x509/default-host  0.74
/x86_64/migration/precopy/tcp/tls/x509/reject-anon-client  0.71
/x86_64/migration/multifd/tcp/tls/x509/reject-anon-client  0.68
/x86_64/migration/precopy/tcp/tls/psk/mismatch  0.63
/x86_64/migration/validate_uuid_src_not_set  0.59
/x86_64/migration/validate_uuid  0.54
/x86_64/migration/validate_uuid_dst_not_set  0.53
/x86_64/migration/bad_dest  0.41
/x86_64/migration/validate_uuid_error  0.31

The auto-converge and xbzrle tests are top because they both inherantly
*need* todo multiple interations in order to exercise the desired
code paths.

The post-copy tests are all up there because we always do one iteration
of pre-copy before switching to post-copy and we need to ensure that we
don't complete before getting to the post-copy bit.

I think we can optimize the post-copy bit though. Only 1 of the
post-copy tests really needs to go through a full pre-copy iteration
to get good code coverage.  For the other post-copy tests we can change
to let it copy 10 MBs of data in pre-copy mode and then switch to
post-copy.

Also in

  commit 1bfc8dde505f1e6a92697c52aa9b09e81b54c78f
  Author: Dr. David Alan Gilbert <dgilbert@redhat.com>
  Date:   Mon Mar 6 15:26:12 2023 +0000

    tests/migration: Tweek auto converge limits check

we cut the bandwidth by factor of x10 to ensure reliability. I think
that was perhaps too aggressive. If we bump it back up to say 10 MB/sec
that's still better than the original 30 MB/sec, perhaps enough to give
us reliability, while cutting time of other tests by 70%

Daniel P. Berrangé (2):
  tests/qtest: capture RESUME events during migration
  tests/qtest: make more migration pre-copy scenarios run non-live

 tests/qtest/migration-helpers.c | 12 +++++++++---
 tests/qtest/migration-helpers.h |  1 +
 tests/qtest/migration-test.c    | 34 ++++++++++++++++++++++++++-------
 3 files changed, 37 insertions(+), 10 deletions(-)

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2.40.0