[PATCH] init: calibrate: don't print out bogomips value on boot

[PATCH] init: calibrate: don't print out bogomips value on boot

[Will Deacon]

BogoMIPs is a confusing concept to the ill-informed, so allow
architectures to print it only if they find it worthwhile. The delay
calibration code should stick to lpj and avoid trying to draw any
correlation with BogoMIPs, which may be a fixed value derived from a
timer frequency independent of the CPU clock speed.

Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
---

This is mostly cosmetic, but we've killed bogomips from the cpuinfo
on ARM and arm64, so this would be the final nail on the coffin...

 init/calibrate.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/init/calibrate.c b/init/calibrate.c
index 520702d..eabc2ca 100644
--- a/init/calibrate.c
+++ b/init/calibrate.c
@@ -135,13 +135,13 @@ static unsigned long calibrate_delay_direct(void)
 		if ((measured_times[max] - estimate) <
 				(estimate - measured_times[min])) {
 			printk(KERN_NOTICE "calibrate_delay_direct() dropping "
-					"min bogoMips estimate %d = %lu\n",
+					"min delay estimate %d = %lu\n",
 				min, measured_times[min]);
 			measured_times[min] = 0;
 			min = max;
 		} else {
 			printk(KERN_NOTICE "calibrate_delay_direct() dropping "
-					"max bogoMips estimate %d = %lu\n",
+					"max delay estimate %d = %lu\n",
 				max, measured_times[max]);
 			measured_times[max] = 0;
 			max = min;
@@ -295,9 +295,7 @@ void calibrate_delay(void)
 	}
 	per_cpu(cpu_loops_per_jiffy, this_cpu) = lpj;
 	if (!printed)
-		pr_cont("%lu.%02lu BogoMIPS (lpj=%lu)\n",
-			lpj/(500000/HZ),
-			(lpj/(5000/HZ)) % 100, lpj);
+		pr_cont("lpj=%lu\n", lpj);
 
 	loops_per_jiffy = lpj;
 	printed = true;
-- 
1.8.2.2

Re: [PATCH] init: calibrate: don't print out bogomips value on boot

[Andrew Morton]

On Wed,  9 Oct 2013 15:57:20 +0100 Will Deacon <will.deacon@arm.com> wrote:

> @@ -295,9 +295,7 @@ void calibrate_delay(void)
>  	}
>  	per_cpu(cpu_loops_per_jiffy, this_cpu) = lpj;
>  	if (!printed)
> -		pr_cont("%lu.%02lu BogoMIPS (lpj=%lu)\n",
> -			lpj/(500000/HZ),
> -			(lpj/(5000/HZ)) % 100, lpj);
> +		pr_cont("lpj=%lu\n", lpj);
>  
>  	loops_per_jiffy = lpj;
>  	printed = true;

Kidding?  BogoMIPS is an industry-standard metric which was established
before many of us were born.  It even has its own wikipedia page!

You have no heart.

Re: [PATCH] init: calibrate: don't print out bogomips value on boot

[Will Deacon]

On Thu, Oct 10, 2013 at 10:52:35PM +0100, Andrew Morton wrote:
> On Wed,  9 Oct 2013 15:57:20 +0100 Will Deacon <will.deacon@arm.com> wrote:
> 
> > @@ -295,9 +295,7 @@ void calibrate_delay(void)
> >  	}
> >  	per_cpu(cpu_loops_per_jiffy, this_cpu) = lpj;
> >  	if (!printed)
> > -		pr_cont("%lu.%02lu BogoMIPS (lpj=%lu)\n",
> > -			lpj/(500000/HZ),
> > -			(lpj/(5000/HZ)) % 100, lpj);
> > +		pr_cont("lpj=%lu\n", lpj);
> >  
> >  	loops_per_jiffy = lpj;
> >  	printed = true;
> 
> Kidding?  BogoMIPS is an industry-standard metric which was established
> before many of us were born.  It even has its own wikipedia page!

Crikey, have you looked at that page? ARM is ominously described as `not
enough data (yet)' when discussing its BogoMIPS `rating'. This is all more
food for the marketing machines :(

> You have no heart.

Maybe I should stop worrying and learn to love the BogoMIPS.

Will