[PATCH] printk time parameter

[Jan Engelhardt <jengelh@linux01.gwdg.de>]

Hello list,


Currently, enabling/disabling printk timestamps is only possible through 
reboot (bootparam) or recompile. I normally do not run with timestamps 
(since syslog handles that in a good manner), but for measuring small 
kernel delays (e.g. irq probing - see parport thread) I needed subsecond 
precision, but then again, just for some minutes rather than all kernel 
messages to come.
The following patch adds a module_param() with which the timestamps can be 
en-/disabled in a live system through 
/sys/modules/printk/parameters/printk_time.

Signed-off-by: Jan Engelhardt <jengelh@gmx.de>

diff --fast -Ndpru linux-2.6.17-rc5~/kernel/printk.c linux-2.6.17-rc5+/kernel/printk.c
--- linux-2.6.17-rc5~/kernel/printk.c	2006-06-03 13:30:10.000000000 +0200
+++ linux-2.6.17-rc5+/kernel/printk.c	2006-06-05 11:49:11.655884000 +0200
@@ -24,6 +24,7 @@
 #include <linux/console.h>
 #include <linux/init.h>
 #include <linux/module.h>
+#include <linux/moduleparam.h>
 #include <linux/interrupt.h>			/* For in_interrupt() */
 #include <linux/config.h>
 #include <linux/delay.h>
@@ -436,6 +437,7 @@ static int printk_time = 1;
 #else
 static int printk_time = 0;
 #endif
+module_param(printk_time, int, S_IRUGO | S_IWUSR);
 
 static int __init printk_time_setup(char *str)
 {
#<<eof>>


Jan Engelhardt
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