Re: PATCH: Create new LED trigger for CPU activity (ledtrig-cpu) (UPDATED)

[Thomas Tuttle]

On July 06 at 00:39 EDT, Andrew Morton hastily scribbled:
> On Wed, 5 Jul 2006 22:48:17 -0400
> "Thomas Tuttle" <thinkinginbinary@xxxxxxxxx> wrote:

Omigod, Andrew Morton replied to my email.  Cool.  Linux rocks.

> > Here is a new version of the patch, incorporating code style tips from
> > Randy Dunlap <rdunlap@xxxxxxxxxxxx>, and based on 2.6.17-git25, rather
> > than 2.6.17.1.
> > 
> > I noticed that there's a Heartbeat LED trigger in the git version.  I
> > hope this isn't too similar.
> > 
>
> <snip>
> 
> waaaaaaaaaaay too many config options.  Make up your mind, man ;)

Okay, this new patch includes user and system, excludes iowait, and
makes nice configurable by a boolean module parameter called
include_nice, with the default being to exclude nice time.

> > +cputime64_t last_cputime;
> static.
Done.

> > +static void __exit ledtrig_cpu_exit(void)
> > +{
> > +	del_timer(&ledtrig_cpu_timer);
> del_timer_sync().
Done.

I also made the trigger track the last state of the LED, and avoid
sending a trigger event unless the state has actually changed.  And I
made it turn off the LED when the trigger is unloaded.

--Thomas Tuttle
diff -udrN linux-2.6.17-git25/drivers/leds/Kconfig linux-2.6.17-git25-mine/drivers/leds/Kconfig
--- linux-2.6.17-git25/drivers/leds/Kconfig	2006-07-05 22:11:45.000000000 -0400
+++ linux-2.6.17-git25-mine/drivers/leds/Kconfig	2006-07-06 09:23:18.000000000 -0400
@@ -93,6 +93,13 @@
 	  This allows LEDs to be controlled by IDE disk activity.
 	  If unsure, say Y.
 
+config LEDS_TRIGGER_CPU
+	tristate "LED CPU Trigger"
+	depends LEDS_TRIGGERS
+	help
+	  This allows LEDs to be controlled by CPU activity.
+	  If unsure, say Y.
+
 config LEDS_TRIGGER_HEARTBEAT
 	tristate "LED Heartbeat Trigger"
 	depends LEDS_TRIGGERS
diff -udrN linux-2.6.17-git25/drivers/leds/ledtrig-cpu.c linux-2.6.17-git25-mine/drivers/leds/ledtrig-cpu.c
--- linux-2.6.17-git25/drivers/leds/ledtrig-cpu.c	1969-12-31 19:00:00.000000000 -0500
+++ linux-2.6.17-git25-mine/drivers/leds/ledtrig-cpu.c	2006-07-06 09:48:43.000000000 -0400
@@ -0,0 +1,89 @@
+/*
+ * LED CPU Activity Trigger
+ *
+ * Copyright 2006 Thomas Tuttle
+ *
+ * Author: Thomas Tuttle <thinkinginbinary@xxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/timer.h>
+#include <linux/leds.h>
+#include <linux/kernel_stat.h>
+#include <asm/cputime.h>
+
+MODULE_AUTHOR("Thomas Tuttle <thinkinginbinary@xxxxxxxxx>");
+MODULE_DESCRIPTION("LED CPU Activity Trigger");
+MODULE_PARM_DESC(include_nice, "Turn LED on for nice CPU time");
+MODULE_LICENSE("GPL");
+
+static int include_nice = 0;
+
+module_param(include_nice, bool, 0);
+
+#define UPDATE_INTERVAL (5) /* delay between updates, in ms */
+
+static void ledtrig_cpu_timerfunc(unsigned long data);
+
+DEFINE_LED_TRIGGER(ledtrig_cpu);
+static DEFINE_TIMER(ledtrig_cpu_timer, ledtrig_cpu_timerfunc, 0, 0);
+
+static cputime64_t cpu_usage(void)
+{
+	int i;
+	cputime64_t time = cputime64_zero;
+
+	for_each_possible_cpu(i) {
+		time = cputime64_add(time, kstat_cpu(i).cpustat.user);
+		if (include_nice)
+			time = cputime64_add(time, kstat_cpu(i).cpustat.nice);
+		time = cputime64_add(time, kstat_cpu(i).cpustat.system);
+	}
+
+	return time;
+}
+
+static enum led_brightness last_led_state;
+static cputime64_t last_cputime;
+
+static void ledtrig_cpu_timerfunc(unsigned long data)
+{
+	cputime64_t this_cputime = cpu_usage();
+	/* XXX: This assumes that cputime64_t can be subtracted.
+	 * Nobody has defined cputime64_sub, so I had to do this instead. */
+	cputime64_t used_cputime = this_cputime - last_cputime;
+	enum led_brightness led_state = (used_cputime > 0) ? LED_FULL : LED_OFF;
+	if (led_state != last_led_state)
+		led_trigger_event(ledtrig_cpu, led_state);
+	last_led_state = led_state;
+	last_cputime = cpu_usage();
+
+	mod_timer(&ledtrig_cpu_timer, jiffies + msecs_to_jiffies(UPDATE_INTERVAL));
+}
+
+static int __init ledtrig_cpu_init(void)
+{
+	led_trigger_register_simple("cpu", &ledtrig_cpu);
+	led_trigger_event(ledtrig_cpu, LED_OFF);
+	last_led_state = LED_OFF;
+	last_cputime = cpu_usage();
+	mod_timer(&ledtrig_cpu_timer, jiffies + msecs_to_jiffies(UPDATE_INTERVAL));
+	return 0;
+}
+
+static void __exit ledtrig_cpu_exit(void)
+{
+	del_timer_sync(&ledtrig_cpu_timer);
+	led_trigger_event(ledtrig_cpu, LED_OFF);
+	led_trigger_unregister_simple(ledtrig_cpu);
+}
+
+module_init(ledtrig_cpu_init);
+module_exit(ledtrig_cpu_exit);
diff -udrN linux-2.6.17-git25/drivers/leds/Makefile linux-2.6.17-git25-mine/drivers/leds/Makefile
--- linux-2.6.17-git25/drivers/leds/Makefile	2006-07-05 22:11:45.000000000 -0400
+++ linux-2.6.17-git25-mine/drivers/leds/Makefile	2006-07-05 22:40:52.000000000 -0400
@@ -16,4 +16,5 @@
 # LED Triggers
 obj-$(CONFIG_LEDS_TRIGGER_TIMER)	+= ledtrig-timer.o
 obj-$(CONFIG_LEDS_TRIGGER_IDE_DISK)	+= ledtrig-ide-disk.o
+obj-$(CONFIG_LEDS_TRIGGER_CPU)		+= ledtrig-cpu.o
 obj-$(CONFIG_LEDS_TRIGGER_HEARTBEAT)	+= ledtrig-heartbeat.o

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