Add file lock to support xdist -n options #155
Conversation
The temp_file is generated by verilog import function and might be manipulated at the same time when doing py.test -n X provided by xdist. To protect the critical section, a simple way is to use fcntl file lock. See http://stackoverflow.com/questions/9907616/python-fcntl-does-not-lock-as-expected
This is to guarantee the release of the file lock. Otherwise, the test will stuck.
|
We probably need to fix the tests that are failing TravisCI before merging this pull request, right? This can probably wait until next week while we get lab1 out. |
|
Interesting, it didn't fail locally. I need to reproduce that failure ... |
|
I think you might want to try pytest fixtures: They ensure a test suite that has shared resources only creates that resource once at test collection time and then all the tests could use the same generated Verilog. This will be especially helpful for large blocks that take a long time to verilate/compile. Might be good to try pytest fixtures combined with some checking logic in verilator_sim.py that has better Exception checking if when accessing the file in an unexpected state. |
Previously the reason why verilog import with -n option fails is that creating and checking the tmp file is not atomic. It is possible for two threads to create the tmp file at the same time (but only one file) and after one thread deletes the tmp file the other thread cannot find it.
Basically I wrap the code fragment that manipulates files with a fcntl file lock for verilog import and systemc import.
I also add -n option to Travis CI to show the performance difference.