[PATCH] Better "Losing Ticks" Error Message

[PATCH] Better "Losing Ticks" Error Message

[timothy parkinson]

Andrew,

Seems like a lot of people see the below error message, but aren't quite sure
why it happens or how to fix it.  I sure didn't.

Here's my attempt at remedying that - Should apply cleanly against 2.6.1.

Thanks,
Timothy

diff -urN linux-2.6.1-orig/arch/i386/kernel/timers/timer_tsc.c linux-2.6.1/arch/i386/kernel/timers/timer_tsc.c
--- linux-2.6.1-orig/arch/i386/kernel/timers/timer_tsc.c	2004-01-09 01:59:46.000000000 -0500
+++ linux-2.6.1/arch/i386/kernel/timers/timer_tsc.c	2004-01-23 21:16:24.000000000 -0500
@@ -232,9 +232,13 @@
 		/* sanity check to ensure we're not always losing ticks */
 		if (lost_count++ > 100) {
 			printk(KERN_WARNING "Losing too many ticks!\n");
-			printk(KERN_WARNING "TSC cannot be used as a timesource."
-					" (Are you running with SpeedStep?)\n");
-			printk(KERN_WARNING "Falling back to a sane timesource.\n");
+			printk(KERN_WARNING "TSC cannot be used as a timesource.  ");
+			printk(KERN_WARNING "Possible reasons for this are:\n");
+			printk(KERN_WARNING "  You're running with Speedstep,\n");
+			printk(KERN_WARNING "  You don't have DMA enabled for your hard disk (see hdparm),\n");
+			printk(KERN_WARNING "  Incorrect TSC synchronization on an SMP system (see dmesg).\n");
+			printk(KERN_WARNING "Falling back to a sane timesource now.\n");
+
 			clock_fallback();
 		}
 	} else

Re: [PATCH] Better "Losing Ticks" Error Message

[Nikita Danilov]

timothy parkinson writes:
 > 
 > Andrew,
 > 
 > Seems like a lot of people see the below error message, but aren't quite sure
 > why it happens or how to fix it.  I sure didn't.
 > 
 > Here's my attempt at remedying that - Should apply cleanly against 2.6.1.
 > 
 > Thanks,
 > Timothy
 > 
 > diff -urN linux-2.6.1-orig/arch/i386/kernel/timers/timer_tsc.c linux-2.6.1/arch/i386/kernel/timers/timer_tsc.c
 > --- linux-2.6.1-orig/arch/i386/kernel/timers/timer_tsc.c	2004-01-09 01:59:46.000000000 -0500
 > +++ linux-2.6.1/arch/i386/kernel/timers/timer_tsc.c	2004-01-23 21:16:24.000000000 -0500
 > @@ -232,9 +232,13 @@
 >  		/* sanity check to ensure we're not always losing ticks */
 >  		if (lost_count++ > 100) {
 >  			printk(KERN_WARNING "Losing too many ticks!\n");
 > -			printk(KERN_WARNING "TSC cannot be used as a timesource."
 > -					" (Are you running with SpeedStep?)\n");
 > -			printk(KERN_WARNING "Falling back to a sane timesource.\n");
 > +			printk(KERN_WARNING "TSC cannot be used as a timesource.  ");
 > +			printk(KERN_WARNING "Possible reasons for this are:\n");
 > +			printk(KERN_WARNING "  You're running with Speedstep,\n");
 > +			printk(KERN_WARNING "  You don't have DMA enabled for your hard disk (see hdparm),\n");
 > +			printk(KERN_WARNING "  Incorrect TSC synchronization on an SMP system (see dmesg).\n");

+#ifdef CONFIG_KGDB
+			printk(KERN_WARNING "  You're single-stepping under kgdb (see what you are doing).\n");
+#endif

Modulo that person debugging kernel with kgdb probably understands this
anyway.

 > +			printk(KERN_WARNING "Falling back to a sane timesource now.\n");
 > +

Nikita.

Re: [PATCH] Better "Losing Ticks" Error Message

[Pavel Machek]

Hi!
> 
> Andrew,
> 
> Seems like a lot of people see the below error message, but aren't quite sure
> why it happens or how to fix it.  I sure didn't.
> 
> Here's my attempt at remedying that - Should apply cleanly against 2.6.1.
> 
> Thanks,
> Timothy
> 
> diff -urN linux-2.6.1-orig/arch/i386/kernel/timers/timer_tsc.c linux-2.6.1/arch/i386/kernel/timers/timer_tsc.c
> --- linux-2.6.1-orig/arch/i386/kernel/timers/timer_tsc.c	2004-01-09 01:59:46.000000000 -0500
> +++ linux-2.6.1/arch/i386/kernel/timers/timer_tsc.c	2004-01-23 21:16:24.000000000 -0500
> @@ -232,9 +232,13 @@
>  		/* sanity check to ensure we're not always losing ticks */
>  		if (lost_count++ > 100) {
>  			printk(KERN_WARNING "Losing too many ticks!\n");
> -			printk(KERN_WARNING "TSC cannot be used as a timesource."
> -					" (Are you running with SpeedStep?)\n");
> -			printk(KERN_WARNING "Falling back to a sane timesource.\n");
> +			printk(KERN_WARNING "TSC cannot be used as a timesource.  ");
> +			printk(KERN_WARNING "Possible reasons for this are:\n");
> +			printk(KERN_WARNING "  You're running with Speedstep,\n");
> +			printk(KERN_WARNING "  You don't have DMA enabled for your hard disk (see hdparm),\n");
> +			printk(KERN_WARNING "  Incorrect TSC synchronization on an SMP system (see dmesg).\n");
> +			printk(KERN_WARNING "Falling back to a sane timesource now.\n");
> +
>  			clock_fallback();
>  		}
>  	} else

If something, make it "Loosing too many ticks, TSC cannot be used as a
timesource (see Documentation/time.txt)". We do not want 7 lines of
messages....
								Pavel
-- 
When do you have a heart between your knees?
[Johanka's followup: and *two* hearts?]