torture: Make thread detection more robust by using lspcu

For consecutive numbers the lscpu command collapses the output and just
shows the range with start and end. The processors are numbered that
way on POWER8.

    $ sudo ppc64_cpu --smt=8
    $ lscpu | grep '^NUMA node'
    NUMA node(s):                    2
    NUMA node0 CPU(s):               0-79
    NUMA node8 CPU(s):               80-159

This causes the heuristic to detect the number threads per core, looking
for the number after the first comma, to fail, and QEMU aborts because of
invalid arguments.

    $ lscpu | grep '^NUMA node0' | sed -e 's/^[^,-]*(,|\-)\([0-9]*\),.*$/\1/'
    NUMA node0 CPU(s):               0-79

But the lscpu command shows the number of threads per core:

    $ sudo ppc64_cpu --smt=8
    $ lscpu | grep 'Thread(s) per core'
    Thread(s) per core:              8
    $ sudo ppc64_cpu --smt=off
    $ lscpu | grep 'Thread(s) per core'
    Thread(s) per core:              1

This commit therefore directly uses that value and replaces use of grep
with "sed -n" and its "p" command.

Signed-off-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/tools/testing/selftests/rcutorture/bin/functions.sh b/tools/testing/selftests/rcutorture/bin/functions.sh
index c35ba24f994c36b82b94e7536d8715fc677b599c..66d0414d8e4bc3e9fba3ddb394697e825cce9624 100644 (file)
--- a/tools/testing/selftests/rcutorture/bin/functions.sh
+++ b/tools/testing/selftests/rcutorture/bin/functions.sh
@@ -301,7 +301,7 @@ specify_qemu_cpus () {
                        echo $2 -smp $3
                        ;;
                qemu-system-ppc64)
-                       nt="`lscpu | grep '^NUMA node0' | sed -e 's/^[^,]*,\([0-9]*\),.*$/\1/'`"
+                       nt="`lscpu | sed -n 's/^Thread(s) per core:\s*//p'`"
                        echo $2 -smp cores=`expr \( $3 + $nt - 1 \) / $nt`,threads=$nt
                        ;;
                esac