linux-kernel - Re: [PATCH] init: skip calibration delay if previously done

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Message-ID: <1307138409.14598.52.camel@Joe-Laptop>
Date:	Fri, 03 Jun 2011 15:00:09 -0700
From:	Joe Perches <joe@...ches.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	David Daney <ddaney@...iumnetworks.com>,
	Sameer Nanda <snanda@...omium.org>,
	ext-phil.2.carmody@...ia.com, Tim.Deegan@...rix.com,
	jbeulich@...ell.com, snanda@...gle.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] init: skip calibration delay if previously done

On Fri, 2011-06-03 at 14:45 -0700, Andrew Morton wrote:
> But the whole thing is a bit weird.  Does this look better?
> Make these messages more gramatically pleasing, more consistent and remove
> strange ellipses.

or maybe something like this:

 init/calibrate.c |   34 ++++++++++++++++++++--------------
 1 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/init/calibrate.c b/init/calibrate.c
index cfd7000..827a45c 100644
--- a/init/calibrate.c
+++ b/init/calibrate.c
@@ -246,32 +246,38 @@ recalibrate:
 	return lpj;
 }
 
+static DEFINE_PER_CPU(unsigned long, cpu_loops_per_jiffy) = { 0 };
+
 void __cpuinit calibrate_delay(void)
 {
+	int this_cpu = smp_processor_id();
 	static bool printed;
+	const char *msg;
 
-	if (preset_lpj) {
+	if (per_cpu(cpu_loops_per_jiffy, this_cpu)) {
+		loops_per_jiffy = per_cpu(cpu_loops_per_jiffy, this_cpu);
+		msg = " CPU previously calibrated";
+	} else if (preset_lpj) {
 		loops_per_jiffy = preset_lpj;
-		if (!printed)
-			pr_info("Calibrating delay loop (skipped) "
-				"preset value.. ");
+		msg = " preset value";
 	} else if ((!printed) && lpj_fine) {
 		loops_per_jiffy = lpj_fine;
-		pr_info("Calibrating delay loop (skipped), "
-			"value calculated using timer frequency.. ");
+		msg = " using timer frequency";
 	} else if ((loops_per_jiffy = calibrate_delay_direct()) != 0) {
-		if (!printed)
-			pr_info("Calibrating delay using timer "
-				"specific routine.. ");
+		msg = " using timer specific routine";
 	} else {
-		if (!printed)
-			pr_info("Calibrating delay loop... ");
+		pr_info("Calibrating delay loop...\n");
 		loops_per_jiffy = calibrate_delay_converge();
+		per_cpu(cpu_loops_per_jiffy, this_cpu) = loops_per_jiffy;
+		msg = "";
 	}
-	if (!printed)
-		pr_cont("%lu.%02lu BogoMIPS (lpj=%lu)\n",
+
+	if (!printed) {
+		pr_info("Delay loop calibration:%s %lu.%02lu BogoMIPS (lpj=%lu)\n",
+			msg,
 			loops_per_jiffy/(500000/HZ),
 			(loops_per_jiffy/(5000/HZ)) % 100, loops_per_jiffy);
 
-	printed = true;
+		printed = true;
+	}
 }


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