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Commit 5a90cf20 authored by John Stultz's avatar John Stultz Committed by Andi Kleen
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[PATCH] x86: Log reason why TSC was marked unstable 



Change mark_tsc_unstable() so it takes a string argument, which holds the
reason the TSC was marked unstable.

This is then displayed the first time mark_tsc_unstable is called.

This should help us better debug why the TSC was marked unstable on certain
systems and allow us to make sure we're not being overly paranoid when
throwing out this troublesome clocksource.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
parent 27142219

arch/i386/kernel/cpu/cyrix.c

+1 −1
Original line number Diff line number Diff line
@@ -279,7 +279,7 @@ static void __cpuinit init_cyrix(struct cpuinfo_x86 *c) 
		 */  

		if (vendor == PCI_VENDOR_ID_CYRIX &&

	 (device == PCI_DEVICE_ID_CYRIX_5510 || device == PCI_DEVICE_ID_CYRIX_5520))

			mark_tsc_unstable();

			mark_tsc_unstable("cyrix 5510/5520 detected");

	}

#endif

		c->x86_cache_size=16;	/* Yep 16K integrated cache thats it */

arch/i386/kernel/tsc.c

+3 −2
Original line number Diff line number Diff line
@@ -233,7 +233,7 @@ time_cpufreq_notifier(struct notifier_block *nb, unsigned long val, void *data) 
				 * TSC based sched_clock turns

				 * to junk w/ cpufreq

				 */

				mark_tsc_unstable();

				mark_tsc_unstable("cpufreq changes");

			}

		}

	}
@@ -281,11 +281,12 @@ static struct clocksource clocksource_tsc = { 
				  CLOCK_SOURCE_MUST_VERIFY,

};



void mark_tsc_unstable(void)

void mark_tsc_unstable(char *reason)

{

	if (!tsc_unstable) {

		tsc_unstable = 1;

		tsc_enabled = 0;

		printk("Marking TSC unstable due to: %s.\n", reason);

		/* Can be called before registration */

		if (clocksource_tsc.mult)

			clocksource_change_rating(&clocksource_tsc, 0);

arch/x86_64/kernel/time.c

+1 −1
Original line number Diff line number Diff line
@@ -397,7 +397,7 @@ void __init time_init(void) 
		cpu_khz = tsc_calibrate_cpu_khz();



	if (unsynchronized_tsc())

		mark_tsc_unstable();

		mark_tsc_unstable("TSCs unsynchronized");



	if (cpu_has(&boot_cpu_data, X86_FEATURE_RDTSCP))

		vgetcpu_mode = VGETCPU_RDTSCP;

arch/x86_64/kernel/tsc.c

+3 −2
Original line number Diff line number Diff line
@@ -111,7 +111,7 @@ static int time_cpufreq_notifier(struct notifier_block *nb, unsigned long val, 


		tsc_khz = cpufreq_scale(tsc_khz_ref, ref_freq, freq->new);

		if (!(freq->flags & CPUFREQ_CONST_LOOPS))

			mark_tsc_unstable();

			mark_tsc_unstable("cpufreq changes");

	}



	set_cyc2ns_scale(tsc_khz_ref);
@@ -199,10 +199,11 @@ static struct clocksource clocksource_tsc = { 
	.vread			= vread_tsc,

};



void mark_tsc_unstable(void)

void mark_tsc_unstable(char *reason)

{

	if (!tsc_unstable) {

		tsc_unstable = 1;

		printk("Marking TSC unstable due to %s\n", reason);

		/* Change only the rating, when not registered */

		if (clocksource_tsc.mult)

			clocksource_change_rating(&clocksource_tsc, 0);

arch/x86_64/kernel/tsc_sync.c

+1 −1
Original line number Diff line number Diff line
@@ -138,7 +138,7 @@ void __cpuinit check_tsc_sync_source(int cpu) 
		printk("\n");

		printk(KERN_WARNING "Measured %Ld cycles TSC warp between CPUs,"

				    " turning off TSC clock.\n", max_warp);

		mark_tsc_unstable();

		mark_tsc_unstable("check_tsc_sync_source failed");

		nr_warps = 0;

		max_warp = 0;

		last_tsc = 0;