intermittent failure of CompilationCacheTest.ExpectQuerySuccessConcurrent

[skimo-openhub]

I got this error message on a run of test.sh on 806e3b066a6a841786be4dde38357c972816dcaf:

[----------] 7 tests from CompilationCacheTest
[ RUN      ] CompilationCacheTest.ExpectQuerySuccess
[       OK ] CompilationCacheTest.ExpectQuerySuccess (3558 ms)
[ RUN      ] CompilationCacheTest.ExpectQuerySuccessConcurrent
unknown file: Failure
C++ exception with description "Error at relative precision: 1e-06, #operations: 32, maxValue: 0.994372, maxDiff: 0.723828, random seed: 18446744073709551615" thrown in the test body.
[  FAILED  ] CompilationCacheTest.ExpectQuerySuccessConcurrent (1869 ms)

Unfortunately, the seed is not helpful. I'm unable to reproduce the problem.

When submitting a bug report, please include the following information (where relevant):

• OS: Linux
• How you installed TC (docker, conda, source): source
• GCC/GXX version (if compiling from source): gcc-6 (Ubuntu 6.4.0-8ubuntu1) 6.4.0 20171010
• LLVM/Tapir git hash used (if compiling from source): clang version 5.0.0 (https://github.com/wsmoses/Tapir-Clang 2637f015d66418964aa0225534c004dd71a174b8) (https://github.com/wsmoses/Tapir-LLVM ec3ad2b8d3810dde9c0aaccf3f3f971144d90bc2)

[skimo-openhub]

Just go another one:

[----------] 7 tests from CompilationCacheTest
[ RUN      ] CompilationCacheTest.ExpectQuerySuccess
[       OK ] CompilationCacheTest.ExpectQuerySuccess (3549 ms)
[ RUN      ] CompilationCacheTest.ExpectQuerySuccessConcurrent
unknown file: Failure
C++ exception with description "Error at relative precision: 1e-06, #operations: 32, maxValue: 0.999295, maxDiff: 0.619382, random seed: 18446744073709551615" thrown in the test body.
[  FAILED  ] CompilationCacheTest.ExpectQuerySuccessConcurrent (1868 ms)

[thetheodor]

I have never observed this. I'll try to bump up the number of parallel tasks to see if this pops up.