Opened 5 years ago

Closed 5 years ago

#7656 closed bug (fixed)

qsemn001 randomly fails on OS X x86

Reported by: igloo Owned by:
Priority: normal Milestone:
Component: libraries/base Version: 7.7
Keywords: Cc:
Operating System: Unknown/Multiple Architecture: Unknown/Multiple
Type of failure: None/Unknown Test Case:
Blocked By: Blocking:
Related Tickets: Differential Rev(s):
Wiki Page:


qsemn001 randomly fails on OS X x86 (119 times out of 1000), but never on Linux amd64 (tried 1000 times).


$ make CLEANUP=1 TEST=qsemn001 WAY=normal
python ../../../testsuite/driver/  -e ghc_compiler_always_flags="'-fforce-recomp -dcore-lint -dcmm-lint -dno-debug-output -no-user-package-db -rtsopts '" -e ghc_debugged=False -e ghc_with_native_codegen=1 -e ghc_with_vanilla=1 -e ghc_with_dynamic=1 -e ghc_with_profiling=0 -e ghc_with_threaded_rts=1 -e ghc_with_dynamic_rts=1 -e ghc_with_interpreter=1 -e ghc_unregisterised=0 -e ghc_dynamic_by_default=False -e ghc_with_smp=1 -e ghc_with_llvm=0 -e windows=False -e darwin=True -e in_tree_compiler=True -e clean_only=False --rootdir=. --config=../../../testsuite/config/ghc -e 'config.confdir="../../../testsuite/config"' -e 'config.compiler="/Users/ian/ghc/git/val32/inplace/bin/ghc-stage2"' -e 'config.ghc_pkg="/Users/ian/ghc/git/val32/inplace/bin/ghc-pkg"' -e 'config.hp2ps="/Users/ian/ghc/git/val32/inplace/bin/hp2ps"' -e 'config.hpc="/Users/ian/ghc/git/val32/inplace/bin/hpc"' -e '"gs"' -e 'config.platform="i386-apple-darwin"' -e 'config.os="darwin"' -e 'config.arch="i386"' -e 'config.wordsize="32"' -e 'default_testopts.cleanup="1"' -e 'config.timeout=int() or config.timeout' -e 'config.timeout_prog="../../../testsuite/timeout/install-inplace/bin/timeout"' -e 'config.exeext=""' -e '"/Users/ian/ghc/git/val32/testsuite"'  \
                 --only=qsemn001 \
                 --way=normal \

Timeout is 300
Found 6 .T files...
Beginning test run at Sun Feb  3 21:52:50 GMT 2013
====> Scanning ./all.T
====> Scanning ./Concurrent/all.T
====> Scanning ./IO/all.T
====> Scanning ./Numeric/all.T
====> Scanning ./System/all.T
====> Scanning ./Text.Printf/all.T
=====> qsemn001(normal) 69 of 156 [0, 0, 0]
cd . && '/Users/ian/ghc/git/val32/inplace/bin/ghc-stage2' -fforce-recomp -dcore-lint -dcmm-lint -dno-debug-output -no-user-package-db -rtsopts -fno-ghci-history -o qsemn001 qsemn001.hs    >qsemn001.comp.stderr 2>&1
cd . && ./qsemn001    </dev/null > 2>
Wrong exit code (expected 0 , actual 1 )
test semn
test semn2

qsemn001: "acb" /= "abc"

*** unexpected failure for qsemn001(normal)

OVERALL SUMMARY for test run started at Sun Feb  3 21:52:50 GMT 2013
     156 total tests, which gave rise to
    1068 test cases, of which
       0 caused framework failures
    1067 were skipped

       0 expected passes
       0 had missing libraries
       0 expected failures
       0 unexpected passes
       1 unexpected failures

Unexpected failures:
   .  qsemn001 [bad exit code] (normal)

The actual failure varies:

$ grep "qsemn001:" out | sort | uniq -c
  30 qsemn001: "acb" /= "abc"
  34 qsemn001: "ba" /= "ab"
  55 qsemn001: "bac" /= "abc"

Change History (1)

comment:1 Changed 5 years ago by simonmar

Resolution: fixed
Status: newclosed

Fixed, I hope. It looks like small delays aren't as accurate on OS X as they are on Linux, but in any case this test was fragile so it's a good thing to fix it. It might be a good idea for someone to look into why the delays weren't accurate on OS X, but it may just be that there's only a 20ms resolution for the select timeout or something.

commit 975ea1a7bbd1aa129f5c3b0cb4eb0dfb74780a0b
Author: Simon Marlow <>
Date:   Mon Feb 4 14:38:45 2013 +0000

    Remove the reliance on relative accuracy of short delays (#7656)
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