I gad received some good advice to try using gmake -j X -k check for some X > 1 when running a testsuite in order to speed the process up. So I decided to test that theory with an eye on the results. I was surprised to see that the results when running "gmake -j 8 -k check" differ from a simple "gmake -k check" in the area of go and libmudflap :
1 ) parallel testsuite :
http://gcc.gnu.org/ml/gcc-testresults/2012-12/msg01903.html
2 ) single process testsuite :
http://gcc.gnu.org/ml/gcc-testresults/2012-12/msg01935.html
In parallel we see this for "go" :
=== go tests ===
Running target unix
FAIL: go.test/test/stack.go execution, -O2 -g
=== go Summary ===
# of expected passes 3293
# of unexpected failures 1
# of expected failures 4
# of untested testcases 4
/home/dclarke/pgm/build/gcc-4.7.2_2.6.32-279.14.1.el6.x86_64.004/gcc/testsuite/go/../../gccgo version 4.7.2 (Blastwave.org Inc. time_rfc-3339=2012-12-20 11:23:25+00:00)
While the single process apporach reports :
=== go Summary ===
# of expected passes 3294
# of expected failures 4
# of untested testcases 4
/home/dclarke/pgm/build/gcc-4.7.2_2.6.32-279.14.1.el6.x86_64.004/gcc/testsuite/go/../../gccgo version 4.7.2 (Blastwave.org Inc. time_rfc-3339=2012-12-20 11:23:25+00:00)
Perhaps the go test "go.test/test/stack.go" is somehow sensitive to running on a busy machine? I am only guessing.
The "libmudflap tests" results are wildly different.
So at first glance it appears that the testsuite will in fact product different results if one chooses to use "gmake -j X" for X>1 but I am not sure why. Felt is was worth pointing out as maybe no one else has done the comparison.
Dennis
