<<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 | |
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Blocking | |
CC | |
Operating system | |
Architecture |