The LLVM lit test suites consist of thousands of small independent tests. Due to the number of tests, it can take a long time to run the full suite, even on a high-spec computer. Builds are already distributable across multiple computers available on the same network, using software such as distcc or icecream, so running tests on a single machine becomes a potential bottleneck. One way to speed up running of the tests could be to distribute test execution across many computers too. Lit provides a test sharding mechanism, which allows multiple computers to run parts of the same testsuite in tandem, but this currently assumes access to a single common filesystem, which may not be possible in all cases and a knowledge of which machines the suite can currently be run on.


Soham Dixit


  • James Henderson