Dear Paul, Am 22.02.22 um 18:43 schrieb Paul E. McKenney:
On Tue, Feb 22, 2022 at 01:07:17PM +0100, Paul Menzel wrote:For consecutive numbers *lscpu* 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 | sed -n -e '/^NUMA node0/s/^[^,]*,\([0-9]*\),.*$/\1/p' $ (Before the last patch, the whole line was returned.) $ lscpu | grep '^NUMA node0' | sed -e 's/^[^,-]*(,|\-)\([0-9]*\),.*$/\1/' NUMA node0 CPU(s): 0-79 *lscpu* shows the number of threads per core, so use that value directly. $ 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 Note, the replaced heuristic is also incorrect for that case, where the threads per core are disabled. $ lscpu | sed -n -e '/^NUMA node0/s/^[^,]*,\([0-9]*\),.*$/\1/p' 8 Signed-off-by: Paul Menzel <pmenzel@xxxxxxxxxxxxx>Makes sense, and thank you for chasing this down and for the fix! But should this patch and 1/2 be merged? Or am I confused and they are somehow affecting two different lines of scripting?
You are right. I guess with 1/2 I just wanted to document clearly, what I learned in #sed@xxxxxxxxxxxxxxx, that means, how to avoid using grep, when sed is used.
Kind regards, Paul
--- tools/testing/selftests/rcutorture/bin/functions.sh | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/rcutorture/bin/functions.sh b/tools/testing/selftests/rcutorture/bin/functions.sh index 5cff520955e6..66d0414d8e4b 100644 --- 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 | sed -n -e '/^NUMA node0/s/^[^,]*,\([0-9]*\),.*$/\1/p'`" + nt="`lscpu | sed -n 's/^Thread(s) per core:\s*//p'`" echo $2 -smp cores=`expr \( $3 + $nt - 1 \) / $nt`,threads=$nt ;; esac -- 2.35.1
