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From: paulmck@kernel.org
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
	mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com,
	akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
	josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
	rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
	fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org,
	"Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH tip/core/rcu 03/12] torture: Handle jitter for CPUs that cannot be offlined
Date: Mon,  9 Dec 2019 19:42:08 -0800	[thread overview]
Message-ID: <20191210034217.405-3-paulmck@kernel.org> (raw)
In-Reply-To: <20191210034119.GA32711@paulmck-ThinkPad-P72>

From: "Paul E. McKenney" <paulmck@kernel.org>

Currently, jitter.sh assumes that the underlying hypervisor will be
configured with all CPUs hotpluggable, with the possible exception
of CPU 0.  However, there are installations where the hypervisor
prohibits offlining, which breaks jitter.sh.  This commit therefore
lists the CPUs that cannot be offlined up front, and checks for the
case where no CPU can be offlined in the loop.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 tools/testing/selftests/rcutorture/bin/jitter.sh | 26 ++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/rcutorture/bin/jitter.sh b/tools/testing/selftests/rcutorture/bin/jitter.sh
index 86a217b..30cb5b2 100755
--- a/tools/testing/selftests/rcutorture/bin/jitter.sh
+++ b/tools/testing/selftests/rcutorture/bin/jitter.sh
@@ -25,6 +25,18 @@ n=1
 
 starttime=`gawk 'BEGIN { print systime(); }' < /dev/null`
 
+nohotplugcpus=
+for i in /sys/devices/system/cpu/cpu[0-9]*
+do
+	if test -f $i/online
+	then
+		:
+	else
+		curcpu=`echo $i | sed -e 's/^[^0-9]*//'`
+		nohotplugcpus="$nohotplugcpus $curcpu"
+	fi
+done
+
 while :
 do
 	# Check for done.
@@ -35,13 +47,15 @@ do
 	fi
 
 	# Set affinity to randomly selected online CPU
-	cpus=`grep 1 /sys/devices/system/cpu/*/online |
-		sed -e 's,/[^/]*$,,' -e 's/^[^0-9]*//'`
-
-	# Do not leave out poor old cpu0 which may not be hot-pluggable
-	if [ ! -f "/sys/devices/system/cpu/cpu0/online" ]; then
-		cpus="0 $cpus"
+	if cpus=`grep 1 /sys/devices/system/cpu/*/online 2>&1 |
+		 sed -e 's,/[^/]*$,,' -e 's/^[^0-9]*//'`
+	then
+		:
+	else
+		cpus=
 	fi
+	# Do not leave out non-hot-pluggable CPUs
+	cpus="$cpus $nohotplugcpus"
 
 	cpumask=`awk -v cpus="$cpus" -v me=$me -v n=$n 'BEGIN {
 		srand(n + me + systime());
-- 
2.9.5


  parent reply	other threads:[~2019-12-10  3:43 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-10  3:41 [PATCH tip/core/rcu 0/12] Torture-test updates for v5.6 Paul E. McKenney
2019-12-10  3:42 ` [PATCH tip/core/rcu 01/12] torture: Use gawk instead of awk for systime() function paulmck
2019-12-10  3:42 ` [PATCH tip/core/rcu 02/12] rcutorture: Dispense with Dracut for initrd creation paulmck
2019-12-10  3:42 ` paulmck [this message]
2019-12-10  3:42 ` [PATCH tip/core/rcu 04/12] torture: Handle systems lacking the mpstat command paulmck
2019-12-10  3:42 ` [PATCH tip/core/rcu 05/12] rcutorture: Add worst-case call_rcu() forward-progress results paulmck
2019-12-10  3:42 ` [PATCH tip/core/rcu 06/12] rcutorture: Pull callback forward-progress data into rcu_fwd struct paulmck
2019-12-10  3:42 ` [PATCH tip/core/rcu 07/12] rcutorture: Thread rcu_fwd pointer through forward-progress functions paulmck
2019-12-10  3:42 ` [PATCH tip/core/rcu 08/12] rcutorture: Move to dynamic initialization of rcu_fwds paulmck
2019-12-10  3:42 ` [PATCH tip/core/rcu 09/12] rcutorture: Complete threading rcu_fwd pointers through functions paulmck
2019-12-10  3:42 ` [PATCH tip/core/rcu 10/12] rcutorture: Dynamically allocate rcu_fwds structure paulmck
2019-12-10  3:42 ` [PATCH tip/core/rcu 11/12] torture: Allow "CFLIST" to specify default list of scenarios paulmck
2019-12-10  3:42 ` [PATCH tip/core/rcu 12/12] torture: Hoist calls to lscpu to higher-level kvm.sh script paulmck

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