sparc64: optimize functions that access tick (eae3fc98) · Commits · 戴 / test

arch/sparc/kernel/time_64.c

+13 −9

Original line number	Diff line number	Diff line
		@@ -752,12 +752,10 @@ static unsigned long tb_ticks_per_usec __read_mostly;

		void __delay(unsigned long loops)
		{
		unsigned long bclock, now;
		unsigned long bclock = get_tick();

		bclock = tick_operations.get_tick();
		do {
		now = tick_operations.get_tick();
		} while ((now-bclock) < loops);
		while ((get_tick() - bclock) < loops)
		;
		}
		EXPORT_SYMBOL(__delay);

		@@ -769,7 +767,7 @@ EXPORT_SYMBOL(udelay);

		static u64 clocksource_tick_read(struct clocksource *cs)
		{
		return tick_operations.get_tick();
		return get_tick();
		}

		static void __init get_tick_patch(void)
		@@ -853,13 +851,19 @@ unsigned long long sched_clock(void)
		{
		unsigned long quotient = tick_operations.ticks_per_nsec_quotient;
		unsigned long offset = tick_operations.offset;
		unsigned long ticks = tick_operations.get_tick();

		return ((ticks * quotient) >> SPARC64_NSEC_PER_CYC_SHIFT) - offset;
		/* Use barrier so the compiler emits the loads first and overlaps load
		* latency with reading tick, because reading %tick/%stick is a
		* post-sync instruction that will flush and restart subsequent
		* instructions after it commits.
		*/
		barrier();

		return ((get_tick() * quotient) >> SPARC64_NSEC_PER_CYC_SHIFT) - offset;
		}

		int read_current_timer(unsigned long *timer_val)
		{
		*timer_val = tick_operations.get_tick();
		*timer_val = get_tick();
		return 0;
		}