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authorAlok Kataria <akataria@vmware.com>2008-07-01 11:43:31 -0700
committerIngo Molnar <mingo@elte.hu>2008-07-09 07:43:26 +0200
commit2dbe06faf37b39f9ecffc054dd173b2a1dc2adcd (patch)
tree530104ee7b810420983bcb2674724721ced76d0a /arch/x86/kernel/tsc_64.c
parentbfc0f5947afa5e3a13e55867f4478c8a92c11dca (diff)
x86: merge the TSC cpu-freq code
Unify the TSC cpufreq code. Signed-off-by: Alok N Kataria <akataria@vmware.com> Signed-off-by: Dan Hecht <dhecht@vmware.com> Cc: Dan Hecht <dhecht@vmware.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/tsc_64.c')
-rw-r--r--arch/x86/kernel/tsc_64.c114
1 files changed, 0 insertions, 114 deletions
diff --git a/arch/x86/kernel/tsc_64.c b/arch/x86/kernel/tsc_64.c
index c852ff9bd5d4..80a274b018c2 100644
--- a/arch/x86/kernel/tsc_64.c
+++ b/arch/x86/kernel/tsc_64.c
@@ -16,120 +16,6 @@
extern int tsc_unstable;
extern int tsc_disabled;
-/* Accelerators for sched_clock()
- * convert from cycles(64bits) => nanoseconds (64bits)
- * basic equation:
- * ns = cycles / (freq / ns_per_sec)
- * ns = cycles * (ns_per_sec / freq)
- * ns = cycles * (10^9 / (cpu_khz * 10^3))
- * ns = cycles * (10^6 / cpu_khz)
- *
- * Then we use scaling math (suggested by george@mvista.com) to get:
- * ns = cycles * (10^6 * SC / cpu_khz) / SC
- * ns = cycles * cyc2ns_scale / SC
- *
- * And since SC is a constant power of two, we can convert the div
- * into a shift.
- *
- * We can use khz divisor instead of mhz to keep a better precision, since
- * cyc2ns_scale is limited to 10^6 * 2^10, which fits in 32 bits.
- * (mathieu.desnoyers@polymtl.ca)
- *
- * -johnstul@us.ibm.com "math is hard, lets go shopping!"
- */
-
-DEFINE_PER_CPU(unsigned long, cyc2ns);
-
-void set_cyc2ns_scale(unsigned long cpu_khz, int cpu)
-{
- unsigned long long tsc_now, ns_now;
- unsigned long flags, *scale;
-
- local_irq_save(flags);
- sched_clock_idle_sleep_event();
-
- scale = &per_cpu(cyc2ns, cpu);
-
- rdtscll(tsc_now);
- ns_now = __cycles_2_ns(tsc_now);
-
- if (cpu_khz)
- *scale = (NSEC_PER_MSEC << CYC2NS_SCALE_FACTOR)/cpu_khz;
-
- sched_clock_idle_wakeup_event(0);
- local_irq_restore(flags);
-}
-
-#ifdef CONFIG_CPU_FREQ
-
-/* Frequency scaling support. Adjust the TSC based timer when the cpu frequency
- * changes.
- *
- * RED-PEN: On SMP we assume all CPUs run with the same frequency. It's
- * not that important because current Opteron setups do not support
- * scaling on SMP anyroads.
- *
- * Should fix up last_tsc too. Currently gettimeofday in the
- * first tick after the change will be slightly wrong.
- */
-
-static unsigned int ref_freq;
-static unsigned long loops_per_jiffy_ref;
-static unsigned long tsc_khz_ref;
-
-static int time_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
- void *data)
-{
- struct cpufreq_freqs *freq = data;
- unsigned long *lpj, dummy;
-
- if (cpu_has(&cpu_data(freq->cpu), X86_FEATURE_CONSTANT_TSC))
- return 0;
-
- lpj = &dummy;
- if (!(freq->flags & CPUFREQ_CONST_LOOPS))
-#ifdef CONFIG_SMP
- lpj = &cpu_data(freq->cpu).loops_per_jiffy;
-#else
- lpj = &boot_cpu_data.loops_per_jiffy;
-#endif
-
- if (!ref_freq) {
- ref_freq = freq->old;
- loops_per_jiffy_ref = *lpj;
- tsc_khz_ref = tsc_khz;
- }
- if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
- (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
- (val == CPUFREQ_RESUMECHANGE)) {
- *lpj =
- cpufreq_scale(loops_per_jiffy_ref, ref_freq, freq->new);
-
- tsc_khz = cpufreq_scale(tsc_khz_ref, ref_freq, freq->new);
- if (!(freq->flags & CPUFREQ_CONST_LOOPS))
- mark_tsc_unstable("cpufreq changes");
- }
-
- set_cyc2ns_scale(tsc_khz_ref, freq->cpu);
-
- return 0;
-}
-
-static struct notifier_block time_cpufreq_notifier_block = {
- .notifier_call = time_cpufreq_notifier
-};
-
-static int __init cpufreq_tsc(void)
-{
- cpufreq_register_notifier(&time_cpufreq_notifier_block,
- CPUFREQ_TRANSITION_NOTIFIER);
- return 0;
-}
-
-core_initcall(cpufreq_tsc);
-
-#endif
-
/*
* Make an educated guess if the TSC is trustworthy and synchronized
* over all CPUs.