[2/2] kselftests: Add tests for the preemptoff and irqsoff tracers

Commit Message

Joel Fernandes July 11, 2018, 6:35 a.m. UTC

From: "Joel Fernandes (Google)" <[e-mail]>

Here we add unit tests for the preemptoff and irqsoff tracer by using a
kernel module introduced previously to trigger long preempt or irq
disabled sections in the kernel.

Reviewed-by: Masami Hiramatsu <[e-mail]>
Acked-by: Masami Hiramatsu <[e-mail]>
Signed-off-by: Joel Fernandes (Google) <[e-mail]>
---
 tools/testing/selftests/ftrace/config         |  3 +
 .../test.d/preemptirq/irqsoff_tracer.tc       | 73 +++++++++++++++++++
 2 files changed, 76 insertions(+)
 create mode 100644 tools/testing/selftests/ftrace/test.d/preemptirq/irqsoff_tracer.tc

Comments

Steven Rostedt July 12, 2018, 11:04 p.m. UTC | #1

On Tue, 10 Jul 2018 23:35:40 -0700
Joel Fernandes <[e-mail]> wrote:

> From: "Joel Fernandes (Google)" <[e-mail]>
> 
> Here we add unit tests for the preemptoff and irqsoff tracer by using a
> kernel module introduced previously to trigger long preempt or irq
> disabled sections in the kernel.
> 
> Reviewed-by: Masami Hiramatsu <[e-mail]>
> Acked-by: Masami Hiramatsu <[e-mail]>
> Signed-off-by: Joel Fernandes (Google) <[e-mail]>
> ---
>

I added this to my queue too.

If you are curious to see what's currently in my queue, I just pushed
my queue to my tree:

 git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git

  ftrace/core

Beware, that branch can and will rebase often.

-- Steve
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Patch

diff --git a/tools/testing/selftests/ftrace/config b/tools/testing/selftests/ftrace/config
index b01924c71c09..07db5ab09cc7 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_PREEMPTIRQ_DELAY_TEST=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 100644
index 000000000000..cbd174334a48
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/preemptirq/irqsoff_tracer.tc
@@ -0,0 +1,73 @@ 
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: test for the preemptirqsoff tracer
+
+MOD=preemptirq_delay_test
+
+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 test_mode=preempt delay=500000 || fail
+rmmod $MOD || fail
+modprobe $MOD test_mode=preempt delay=500000 || fail
+rmmod $MOD || fail
+modprobe $MOD test_mode=preempt delay=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 test_mode=irq delay=500000 || fail
+rmmod $MOD || fail
+modprobe $MOD test_mode=irq delay=500000 || fail
+rmmod $MOD || fail
+modprobe $MOD test_mode=irq delay=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