linux-kernel - Re: [PATCH v9 7/7] kselftests: Add tests for the preemptoff and irqsoff tracers

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Date:   Mon, 25 Jun 2018 09:21:02 -0700
From:   Joel Fernandes <joel@...lfernandes.org>
To:     Masami Hiramatsu <mhiramat@...nel.org>
Cc:     linux-kernel@...r.kernel.org, kernel-team@...roid.com,
        Boqun Feng <boqun.feng@...il.com>,
        Byungchul Park <byungchul.park@....com>,
        Erick Reyes <erickreyes@...gle.com>,
        Ingo Molnar <mingo@...hat.com>,
        Julia Cartwright <julia@...com>,
        linux-kselftest@...r.kernel.org,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Paul McKenney <paulmck@...ux.vnet.ibm.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Shuah Khan <shuah@...nel.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Thomas Glexiner <tglx@...utronix.de>,
        Todd Kjos <tkjos@...gle.com>,
        Tom Zanussi <tom.zanussi@...ux.intel.com>,
        Will Deacon <will.deacon@....com>
Subject: Re: [PATCH v9 7/7] kselftests: Add tests for the preemptoff and
 irqsoff tracers

On Mon, Jun 25, 2018 at 10:13:02PM +0900, Masami Hiramatsu wrote:
> Hi Joel,
> 
> On Thu, 21 Jun 2018 15:32:36 -0700
> Joel Fernandes <joel@...lfernandes.org> wrote:
> [...]
> > +++ b/tools/testing/selftests/ftrace/test.d/preemptirq/irqsoff_tracer.tc
> > @@ -0,0 +1,74 @@
> > +#!/bin/sh
> > +# SPDX-License-Identifier: GPL-2.0
> > +# description: test for the preemptirqsoff tracer
> > +
> > +MOD=test_atomic_sections
> > +
> > +fail() {
> > +    reset_tracer
> > +    rmmod $MOD || true
> > +    exit_fail
> > +}
> > +
> > +unsup() { #msg
> > +    reset_tracer
> > +    rmmod $MOD || true
> > +    echo $1
> > +    exit_unsupported
> > +}
> > +
> > +modprobe $MOD || unsup "$MOD module not available"
> > +rmmod $MOD
> > +
> > +grep -q "preemptoff" available_tracers || unsup "preemptoff tracer not enabled"
> > +grep -q "irqsoff" available_tracers || unsup "irqsoff tracer not enabled"
> > +
> > +reset_tracer
> > +
> > +# Simulate preemptoff section for half a second couple of times
> > +echo preemptoff > current_tracer
> > +sleep 1
> > +modprobe test_atomic_sections atomic_mode=preempt atomic_time=500000 || fail
> > +rmmod test_atomic_sections || fail
> > +modprobe test_atomic_sections atomic_mode=preempt atomic_time=500000 || fail
> > +rmmod test_atomic_sections || fail
> > +modprobe test_atomic_sections atomic_mode=preempt atomic_time=500000 || fail
> > +rmmod test_atomic_sections || fail
> 
> Why don't you use $MOD for these operations?

Yes, I will. Thanks for the suggestion.

> > +
> > +cat trace
> > +
> > +# Confirm which tracer
> > +grep -q "tracer: preemptoff" trace || fail
> > +
> > +# Check the end of the section
> > +egrep -q "5.....us : <stack trace>" trace || fail
> > +
> > +# Check for 500ms of latency
> > +egrep -q "latency: 5..... us" trace || fail
> > +
> > +reset_tracer
> > +
> > +# Simulate irqsoff section for half a second couple of times
> > +echo irqsoff > current_tracer
> > +sleep 1
> > +modprobe test_atomic_sections atomic_mode=irq atomic_time=500000 || fail
> > +rmmod test_atomic_sections || fail
> > +modprobe test_atomic_sections atomic_mode=irq atomic_time=500000 || fail
> > +rmmod test_atomic_sections || fail
> > +modprobe test_atomic_sections atomic_mode=irq atomic_time=500000 || fail
> > +rmmod test_atomic_sections || fail
> 
> Ditto.

Done.
 
> Other parts looks good to me.

Cool, updated this patch below as "v9.1" ;-)

thanks!

- Joel

---8<-----------------

From: "Joel Fernandes (Google)" <joel@...lfernandes.org>
Subject: [PATCH v9.1 7/7] kselftests: Add tests for the preemptoff and irqsoff
 tracers

Here we add unit tests for the preemptoff and irqsoff tracer by using a
kernel module introduced previously to trigger atomic sections in the
kernel.

Signed-off-by: Joel Fernandes (Google) <joel@...lfernandes.org>
---
 tools/testing/selftests/ftrace/config         |  3 +
 .../test.d/preemptirq/irqsoff_tracer.tc       | 74 +++++++++++++++++++
 2 files changed, 77 insertions(+)
 create mode 100755 tools/testing/selftests/ftrace/test.d/preemptirq/irqsoff_tracer.tc

diff --git a/tools/testing/selftests/ftrace/config b/tools/testing/selftests/ftrace/config
index b01924c71c09..29588b328345 100644
--- a/tools/testing/selftests/ftrace/config
+++ b/tools/testing/selftests/ftrace/config
@@ -4,3 +4,6 @@ CONFIG_FUNCTION_PROFILER=y
 CONFIG_TRACER_SNAPSHOT=y
 CONFIG_STACK_TRACER=y
 CONFIG_HIST_TRIGGERS=y
+CONFIG_PREEMPT_TRACER=y
+CONFIG_IRQSOFF_TRACER=y
+CONFIG_TEST_ATOMIC_SECTIONS=m
diff --git a/tools/testing/selftests/ftrace/test.d/preemptirq/irqsoff_tracer.tc b/tools/testing/selftests/ftrace/test.d/preemptirq/irqsoff_tracer.tc
new file mode 100755
index 000000000000..2dcd5e4cafb4
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/preemptirq/irqsoff_tracer.tc
@@ -0,0 +1,74 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: test for the preemptirqsoff tracer
+
+MOD=test_atomic_sections
+
+fail() {
+    reset_tracer
+    rmmod $MOD || true
+    exit_fail
+}
+
+unsup() { #msg
+    reset_tracer
+    rmmod $MOD || true
+    echo $1
+    exit_unsupported
+}
+
+modprobe $MOD || unsup "$MOD module not available"
+rmmod $MOD
+
+grep -q "preemptoff" available_tracers || unsup "preemptoff tracer not enabled"
+grep -q "irqsoff" available_tracers || unsup "irqsoff tracer not enabled"
+
+reset_tracer
+
+# Simulate preemptoff section for half a second couple of times
+echo preemptoff > current_tracer
+sleep 1
+modprobe $MOD atomic_mode=preempt atomic_time=500000 || fail
+rmmod $MOD || fail
+modprobe $MOD atomic_mode=preempt atomic_time=500000 || fail
+rmmod $MOD || fail
+modprobe $MOD atomic_mode=preempt atomic_time=500000 || fail
+rmmod $MOD || fail
+
+cat trace
+
+# Confirm which tracer
+grep -q "tracer: preemptoff" trace || fail
+
+# Check the end of the section
+egrep -q "5.....us : <stack trace>" trace || fail
+
+# Check for 500ms of latency
+egrep -q "latency: 5..... us" trace || fail
+
+reset_tracer
+
+# Simulate irqsoff section for half a second couple of times
+echo irqsoff > current_tracer
+sleep 1
+modprobe $MOD atomic_mode=irq atomic_time=500000 || fail
+rmmod $MOD || fail
+modprobe $MOD atomic_mode=irq atomic_time=500000 || fail
+rmmod $MOD || fail
+modprobe $MOD atomic_mode=irq atomic_time=500000 || fail
+rmmod $MOD || fail
+
+cat trace
+
+# Confirm which tracer
+grep -q "tracer: irqsoff" trace || fail
+
+# Check the end of the section
+egrep -q "5.....us : <stack trace>" trace || fail
+
+# Check for 500ms of latency
+egrep -q "latency: 5..... us" trace || fail
+
+reset_tracer
+exit 0
+
-- 
2.18.0.rc2.346.g013aa6912e-goog