legitimate parallel make check?

[IainS <developer at sandoe-acoustics dot co dot uk>]

for the sake of keeping information segregated in log files (and  
balancing out test times)
 I tried the following (from within a regression testing script):

'make -k check-gcc-c RUNTESTFLAGS=$runTEST >${STATE}/$svnRevision- 
check-c-log.txt 2>&1' &
(sleep 2) 'make -k check-gcc-c++ RUNTESTFLAGS=$runTEST >${STATE}/ 
$svnRevision-check-c++-log.txt 2>&1' &
(sleep 2) 'make -k check-gcc-fortran RUNTESTFLAGS=$runTEST >${STATE}/ 
$svnRevision-check-fortran-log.txt 2>&1' &
(sleep 2) ' make -k check-gcc-objc RUNTESTFLAGS=$runTEST >${STATE}/ 
$svnRevision-check-objc-log.txt 2>&1' &
(sleep 2) 'make -k check-gcc-obj-c++ RUNTESTFLAGS=$runTEST >${STATE}/ 
$svnRevision-check-obc++-log.txt 2>&1' &
(sleep 2) 'make -k check-target-libstdc++-v3 RUNTESTFLAGS=$runTEST >$ 
{STATE}/$svnRevision-check-target-libstdc++-log.txt 2>&1'&
(sleep 2) 'make -k check-target-libgomp RUNTESTFLAGS=$runTEST >$ 
{STATE}/$svnRevision-check-target-libgomp-log.txt 2>&1' &

firstly; this actually breaks the make process permanently (I suspect  
a race to make site.exp) unless the parallel jobs are launched with a  
time delay.
by permanently I mean that after trying this - "make check-gcc"  fails  
from the command line until config.status is re-run in the gcc dir.

====

secondly;  if I use  "-k -j3 check-gcc-c "
   together with "-k -j2 check-gcc-fortran " (for example)

I get sporadic bus errors :
/bin/sh: line 1: 67618 Bus error               `if [ -f ${srcdir}/../ 
dejagnu/runtest ] ; then echo ${srcdir}/../dejagnu/runtest ; else echo  
runtest; fi` --tool gfortran --target_board=unix\{-m32,-m64\}  
$runtestflags
make[2]: [check-parallel-gfortran] Error 138 (ignored)

large chunks of tests go silently missing at this point...

===

Am I trying something that is unsupported - or is this is a bug?

===

"make -k -j8 check " is not particularly helpful (a) because it tests  
gmp/mpfr/mpc every time (b) any redirected output is hard to scan for  
problems.

Iain