The `ctest --test-load` option is implemented in `StartNextTests` by not
starting any tests when the load is too high and instead sleeping and
then returning. Prior to commit v3.11.0-rc1~117^2 (CTest: Re-implement
test process handling using libuv, 2017-12-10) our outer loop in
`RunTests` would immediately call `StartNextTests` again. However, now
the `uv_run` loop may simply terminate if there are no tests running
because no events are left pending.
Fix this by converting the sleep in `StartNextTests` into a libuv timer
that it starts instead. This avoids leaving `uv_run` with no pending
events. In the case that there are other running tests this also allows
CTest to detect when they finish even if it during the wait period where
we previously slept.
This regression was not caught by the test suite because it only
verified that we do not start new tests when the load was too high and
not that we proceed to start tests when the load drops. Revise the test
suite to cover both.
Fixes: #18338
In commit v2.8.0~170 (ENH: Added ctest test options PROCESSORS and
RUN_SERIAL, 2009-09-07) CTest learned to track the number of processors
allocated to running tests in order to balance it against the desired
level of parallelism. Extend this idea by introducing a new
`PROCESSOR_AFFINITY` test property to ask that CTest run a test
with the CPU affinity mask set. This will allow a set of tests
that are running concurrently to use disjoint CPU resources.
Refactoring in commit v3.4.0-rc1~390^2~1 (cmCTestMultiProcessHandler:
Refactor RUN_SERIAL implementation, 2015-06-01) forgot to update a code
path for cleaning up after a failed RUN_SERIAL test. This causes an
infinite loop after a RUN_SERIAL test fails. Fix it and add a test.
Add ctest command-line options:
--test-output-size-passed <n>
--test-output-size-failed <n>
to set the amount of test output to store in Test.xml as a command-line
dashboard client.
Add a TestLoad setting to CTest that can be set via a new --test-load
command-line option, CTEST_TEST_LOAD variable, or TEST_LOAD option to
the ctest_test command. Teach cmCTestMultiProcessHandler to measure
the CPU load and avoid starting tests that may take more than the
spare load currently available. The expression
<current_load> + <test_processors> <= <max-load>
must be true to start a new test.
Co-Author: Zack Galbreath <zack.galbreath@kitware.com>
Use the KWSys Process "MergeOutput" option to give each test child
process the same pipe for both stdout and stderr. This allows natural
merging of stdout and stderr together instead of merging on arbitrary
buffered read boundaries as before.
