1 files changed, 8 insertions, 58 deletions

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 26a863a9c2a8..0c40d8b72416 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -104,10 +104,14 @@ int __init notsc_setup(char *str)
 
 __setup("notsc", notsc_setup);
 
+static int no_sched_irq_time;
+
 static int __init tsc_setup(char *str)
 {
         if (!strcmp(str, "reliable"))
                 tsc_clocksource_reliable = 1;
+        if (!strncmp(str, "noirqtime", 9))
+                no_sched_irq_time = 1;
         return 1;
 }
 
@@ -801,6 +805,7 @@ void mark_tsc_unstable(char *reason)
         if (!tsc_unstable) {
                 tsc_unstable = 1;
                 sched_clock_stable = 0;
+                disable_sched_clock_irqtime();
                 printk(KERN_INFO "Marking TSC unstable due to %s\n", reason);
                 /* Change only the rating, when not registered */
                 if (clocksource_tsc.mult)
@@ -892,60 +897,6 @@ static void __init init_tsc_clocksource(void)
         clocksource_register_khz(&clocksource_tsc, tsc_khz);
 }
 
-#ifdef CONFIG_X86_64
-/*
- * calibrate_cpu is used on systems with fixed rate TSCs to determine
- * processor frequency
- */
-#define TICK_COUNT 100000000
-static unsigned long __init calibrate_cpu(void)
-{
-        int tsc_start, tsc_now;
-        int i, no_ctr_free;
-        unsigned long evntsel3 = 0, pmc3 = 0, pmc_now = 0;
-        unsigned long flags;
-
-        for (i = 0; i < 4; i++)
-                if (avail_to_resrv_perfctr_nmi_bit(i))
-                        break;
-        no_ctr_free = (i == 4);
-        if (no_ctr_free) {
-                WARN(1, KERN_WARNING "Warning: AMD perfctrs busy ... "
-                     "cpu_khz value may be incorrect.\n");
-                i = 3;
-                rdmsrl(MSR_K7_EVNTSEL3, evntsel3);
-                wrmsrl(MSR_K7_EVNTSEL3, 0);
-                rdmsrl(MSR_K7_PERFCTR3, pmc3);
-        } else {
-                reserve_perfctr_nmi(MSR_K7_PERFCTR0 + i);
-                reserve_evntsel_nmi(MSR_K7_EVNTSEL0 + i);
-        }
-        local_irq_save(flags);
-        /* start measuring cycles, incrementing from 0 */
-        wrmsrl(MSR_K7_PERFCTR0 + i, 0);
-        wrmsrl(MSR_K7_EVNTSEL0 + i, 1 << 22 | 3 << 16 | 0x76);
-        rdtscl(tsc_start);
-        do {
-                rdmsrl(MSR_K7_PERFCTR0 + i, pmc_now);
-                tsc_now = get_cycles();
-        } while ((tsc_now - tsc_start) < TICK_COUNT);
-
-        local_irq_restore(flags);
-        if (no_ctr_free) {
-                wrmsrl(MSR_K7_EVNTSEL3, 0);
-                wrmsrl(MSR_K7_PERFCTR3, pmc3);
-                wrmsrl(MSR_K7_EVNTSEL3, evntsel3);
-        } else {
-                release_perfctr_nmi(MSR_K7_PERFCTR0 + i);
-                release_evntsel_nmi(MSR_K7_EVNTSEL0 + i);
-        }
-
-        return pmc_now * tsc_khz / (tsc_now - tsc_start);
-}
-#else
-static inline unsigned long calibrate_cpu(void) { return cpu_khz; }
-#endif
-
 void __init tsc_init(void)
 {
         u64 lpj;
@@ -964,10 +915,6 @@ void __init tsc_init(void)
                 return;
         }
 
-        if (cpu_has(&boot_cpu_data, X86_FEATURE_CONSTANT_TSC) &&
-                        (boot_cpu_data.x86_vendor == X86_VENDOR_AMD))
-                cpu_khz = calibrate_cpu();
-
         printk("Detected %lu.%03lu MHz processor.\n",
                         (unsigned long)cpu_khz / 1000,
                         (unsigned long)cpu_khz % 1000);
@@ -987,6 +934,9 @@ void __init tsc_init(void)
         /* now allow native_sched_clock() to use rdtsc */
         tsc_disabled = 0;
 
+        if (!no_sched_irq_time)
+                enable_sched_clock_irqtime();
+
         lpj = ((u64)tsc_khz * 1000);
         do_div(lpj, HZ);
         lpj_fine = lpj;