On 07/19/2010 10:53 PM, Avi Kivity wrote:
On 07/19/2010 11:06 PM, Zachary Amsden wrote:
+static void tsc_khz_changed(void *data)
{
- /* nothing */
+ struct cpufreq_freqs *freq = data;
+ unsigned long khz = 0;
+
+ if (data)
+ khz = freq->new;
+ else if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC))
+ khz = cpufreq_quick_get(raw_smp_processor_id());
+ if (!khz)
+ khz = tsc_khz;
+ __get_cpu_var(cpu_tsc_khz) = khz;
}
Do we really need to cache cpufreq_quick_get()? If it's really
quick, why not just use it everywhere instead of cacheing it? Not a
comment on this patch.
If cpufreq is compiled in, but disabled, it returns zero, so we need
some sort of logic.
Maybe it's better to put it into cpufreq_quick_get(). Inconsistent
APIs that appear to work are bad.
I don't think it's quite so simple; cpufreq is platform independent and
tsc_khz is a platform specific export. It seems cpufreq is designed to
return zero when disabled and we're the unusual ones for wanting to use it.
Zach
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
