Re: [PATCH 0/13] Time: Generic Timeofday Subsystem (v B11)

[john stultz <johnstul@us.ibm.com>]

On Mon, 2005-11-21 at 18:35 -0700, john stultz wrote:
> Still on the TODO list:
> o Fix Frank Sorenson's c3tsc overcompensation problem

Hmmm. It looks like this might be related to the CONFIG_SMP disabling
cpu frequency changes to the cpu_khz value. This fix might solve that
issue.

thanks
-john

diff --git a/arch/i386/kernel/tsc.c b/arch/i386/kernel/tsc.c
index 91a9f7d..15f3c6b 100644
--- a/arch/i386/kernel/tsc.c
+++ b/arch/i386/kernel/tsc.c
@@ -255,9 +255,7 @@ static int time_cpufreq_notifier(struct 
 	if (!ref_freq) {
 		ref_freq = freq->old;
 		loops_per_jiffy_ref = cpu_data[freq->cpu].loops_per_jiffy;
-#ifndef CONFIG_SMP
 		cpu_khz_ref = cpu_khz;
-#endif
 	}
 
 	if ((val == CPUFREQ_PRECHANGE  && freq->old < freq->new) ||
@@ -267,9 +265,9 @@ static int time_cpufreq_notifier(struct 
 			cpu_data[freq->cpu].loops_per_jiffy = cpufreq_scale(loops_per_jiffy_ref, ref_freq, freq->new);
 
 		if (cpu_khz) {
-#ifndef CONFIG_SMP
-			cpu_khz = cpufreq_scale(cpu_khz_ref, ref_freq, freq->new);
-#endif
+			if (num_online_cpus() == 1)
+				cpu_khz = cpufreq_scale(cpu_khz_ref, 
+						ref_freq, freq->new);
 			if (!(freq->flags & CPUFREQ_CONST_LOOPS)) {
 				tsc_khz = cpu_khz;
 				set_cyc2ns_scale(cpu_khz);