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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 20/23] torture: Dump ftrace at shutdown only if requested
Date: Mon, 22 Jun 2020 17:37:49 -0700	[thread overview]
Message-ID: <20200623003752.26872-20-paulmck@kernel.org> (raw)
In-Reply-To: <20200623003731.GA26717@paulmck-ThinkPad-P72>

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

If there is a large number of torture tests running concurrently,
all of which are dumping large ftrace buffers at shutdown time, the
resulting dumping can take a very long time, particularly on systems
with rotating-rust storage.  This commit therefore adds a default-off
torture.ftrace_dump_at_shutdown module parameter that enables
shutdown-time ftrace-buffer dumping.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 Documentation/admin-guide/kernel-parameters.txt | 7 +++++++
 kernel/torture.c                                | 6 +++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a0dcc92..9f11ff8 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5096,6 +5096,13 @@
 			Prevent the CPU-hotplug component of torturing
 			until after init has spawned.
 
+	torture.ftrace_dump_at_shutdown= [KNL]
+			Dump the ftrace buffer at torture-test shutdown,
+			even if there were no errors.  This can be a
+			very costly operation when many torture tests
+			are running concurrently, especially on systems
+			with rotating-rust storage.
+
 	tp720=		[HW,PS2]
 
 	tpm_suspend_pcr=[HW,TPM]
diff --git a/kernel/torture.c b/kernel/torture.c
index a1a4148..1061492 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -45,6 +45,9 @@ MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>");
 static bool disable_onoff_at_boot;
 module_param(disable_onoff_at_boot, bool, 0444);
 
+static bool ftrace_dump_at_shutdown;
+module_param(ftrace_dump_at_shutdown, bool, 0444);
+
 static char *torture_type;
 static int verbose;
 
@@ -527,7 +530,8 @@ static int torture_shutdown(void *arg)
 		torture_shutdown_hook();
 	else
 		VERBOSE_TOROUT_STRING("No torture_shutdown_hook(), skipping.");
-	rcu_ftrace_dump(DUMP_ALL);
+	if (ftrace_dump_at_shutdown)
+		rcu_ftrace_dump(DUMP_ALL);
 	kernel_power_off();	/* Shut down the system. */
 	return 0;
 }
-- 
2.9.5


  parent reply	other threads:[~2020-06-23  0:38 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-23  0:37 [PATCH tip/core/rcu 0/23] Torture-test updates for v5.9 Paul E. McKenney
2020-06-23  0:37 ` [PATCH tip/core/rcu 01/23] torture: Remove qemu dependency on EFI firmware paulmck
2020-06-23  0:37 ` [PATCH tip/core/rcu 02/23] torture: Add script to smoke-test commits in a branch paulmck
2020-06-23  0:37 ` [PATCH tip/core/rcu 03/23] locktorture: Use true and false to assign to bool variables paulmck
2020-06-23  0:37 ` [PATCH tip/core/rcu 04/23] rcutorture: Add races with task-exit processing paulmck
2020-06-23  0:37 ` [PATCH tip/core/rcu 05/23] torture: Set configfile variable to current scenario paulmck
2020-06-23  0:37 ` [PATCH tip/core/rcu 06/23] rcutorture: Handle non-statistic bang-string error messages paulmck
2020-06-23  0:37 ` [PATCH tip/core/rcu 07/23] rcutorture: NULL rcu_torture_current earlier in cleanup code paulmck
2020-06-23  0:37 ` [PATCH tip/core/rcu 08/23] torture: Remove whitespace from identify_qemu_vcpus output paulmck
2020-06-23  0:37 ` [PATCH tip/core/rcu 09/23] torture: Add --allcpus argument to the kvm.sh script paulmck
2020-06-23  0:37 ` [PATCH tip/core/rcu 10/23] rcu/rcutorture: Replace 0 with false paulmck
2020-06-23  0:37 ` [PATCH tip/core/rcu 11/23] torture: Create qemu-cmd in --buildonly runs paulmck
2020-06-23  0:37 ` [PATCH tip/core/rcu 12/23] torture: Add a stop-run capability paulmck
2020-06-23  0:37 ` [PATCH tip/core/rcu 13/23] torture: Abstract out console-log error detection paulmck
2020-06-23  0:37 ` [PATCH tip/core/rcu 14/23] rcutorture: Check for unwatched readers paulmck
2020-06-23  0:37 ` [PATCH tip/core/rcu 15/23] torture: Pass --kmake-arg to all make invocations paulmck
2020-06-23  0:37 ` [PATCH tip/core/rcu 16/23] torture: Correctly summarize build-only runs paulmck
2020-06-23  0:37 ` [PATCH tip/core/rcu 17/23] torture: Improve diagnostic for KCSAN-incapable compilers paulmck
2020-06-23  0:37 ` [PATCH tip/core/rcu 18/23] torture: Add more tracing crib notes to kvm.sh paulmck
2020-06-23  0:37 ` [PATCH tip/core/rcu 19/23] torture: Add kvm-tranform.sh script for qemu-cmd files paulmck
2020-06-23  0:37 ` paulmck [this message]
2020-06-23  0:37 ` [PATCH tip/core/rcu 21/23] torture: Avoid duplicate specification of qemu command paulmck
2020-06-23  0:37 ` [PATCH tip/core/rcu 22/23] torture: Remove obsolete "cd $KVM" paulmck
2020-06-23  0:37 ` [PATCH tip/core/rcu 23/23] rcutorture: Remove KCSAN stubs paulmck

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