<<loop>> with -threaded -feager-blackholing, but only sometimes
While benchmarking the performance of GHC's SMP parallelism, I ran into an issue where (rarely) a test would fail with <<loop>>. I tried hard to reduce this to a single file, which I am attaching to this report.
To reproduce, compile the program with --make -threaded -feager-blackholing -rtsopts -O1 and run multiple times with -Nm with m>=2. In my case, using N8 (on a machine with 8 cores), I once got the error after 35 tries, but sometimes it takes thousands of attempts. I'm also attaching a bash script to compile and run the test repeatedly.
Tested with current HEAD, built on a Intel Xeon E5320, "perf" settings without dynamic linking. But I think I also encountered this behavior in GHC 7.0.3.
Trac metadata
| Trac field | Value |
|---|---|
| Version | 7.1 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |