linux-kernel - [PATCH 26/63] dyndbg-test: change do_prints testpoint to accept a loopct

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Message-ID: <20250125064619.8305-27-jim.cromie@gmail.com>
Date: Fri, 24 Jan 2025 23:45:40 -0700
From: Jim Cromie <jim.cromie@...il.com>
To: linux-kernel@...r.kernel.org,
	jbaron@...mai.com,
	gregkh@...uxfoundation.org,
	ukaszb@...omium.org
Cc: intel-gfx-trybot@...ts.freedesktop.org,
	dri-devel@...ts.freedesktop.org,
	amd-gfx@...ts.freedesktop.org,
	intel-gvt-dev@...ts.freedesktop.org,
	intel-gfx@...ts.freedesktop.org,
	daniel.vetter@...ll.ch,
	tvrtko.ursulin@...ux.intel.com,
	jani.nikula@...el.com,
	ville.syrjala@...ux.intel.com,
	Jim Cromie <jim.cromie@...il.com>
Subject: [PATCH 26/63] dyndbg-test: change do_prints testpoint to accept a loopct

echo 1000 > /sys/module/test_dynamic_debug/parameters/do_prints

This allows its use as a scriptable load generator, to generate
dynamic-prefix-emits for flag combinations vs undecorated printks.
This will make it easy to assess the cost of the prefixing.

NB: the count is an unsigned int, and is *not* clamped currently, but
probably should be.

Signed-off-by: Jim Cromie <jim.cromie@...il.com>
---
 lib/test_dynamic_debug.c | 29 ++++++++++++++++++++---------
 1 file changed, 20 insertions(+), 9 deletions(-)

diff --git a/lib/test_dynamic_debug.c b/lib/test_dynamic_debug.c
index 74b98adc4ed0..5cfc156ca4bb 100644
--- a/lib/test_dynamic_debug.c
+++ b/lib/test_dynamic_debug.c
@@ -16,16 +16,24 @@
 
 /* re-gen output by reading or writing sysfs node: do_prints */
 
-static void do_prints(void); /* device under test */
+static void do_prints(unsigned int); /* device under test */
 static int param_set_do_prints(const char *instr, const struct kernel_param *kp)
 {
-	do_prints();
+	int rc;
+	unsigned int ct;
+
+	rc = kstrtouint(instr, 0, &ct);
+	if (rc) {
+		pr_err("expecting numeric input, using 1 instead\n");
+		ct = 1;
+	}
+	do_prints(ct);
 	return 0;
 }
 static int param_get_do_prints(char *buffer, const struct kernel_param *kp)
 {
-	do_prints();
-	return scnprintf(buffer, PAGE_SIZE, "did do_prints\n");
+	do_prints(1);
+	return scnprintf(buffer, PAGE_SIZE, "did 1 do_prints\n");
 }
 static const struct kernel_param_ops param_ops_do_prints = {
 	.set = param_set_do_prints,
@@ -177,17 +185,20 @@ static void do_levels(void)
 	prdbg(V7);
 }
 
-static void do_prints(void)
+static void do_prints(unsigned int ct)
 {
-	pr_debug("do_prints:\n");
-	do_cats();
-	do_levels();
+	/* maybe clamp this */
+	pr_debug("do-prints %d times:\n", ct);
+	for (; ct; ct--) {
+		do_cats();
+		do_levels();
+	}
 }
 
 static int __init test_dynamic_debug_init(void)
 {
 	pr_debug("init start\n");
-	do_prints();
+	do_prints(1);
 	pr_debug("init done\n");
 	return 0;
 }
-- 
2.48.1