sparc64: access tick function from variable
In timer_64.c tick functions are access via pointer (tick_ops), every time
clock is read, there is one extra load to get to the function.
This patch optimizes it, by accessing functions pointer from value.
Current ched_clock():
sethi %hi(0xb9b400), %g1
ldx [ %g1 + 0x250 ], %g1 ! <tick_ops>
ldx [ %g1 ], %g1
call %g1
nop
sethi %hi(0xb9b400), %g1
ldx [ %g1 + 0x300 ], %g1 ! <timer_ticks_per_nsec_quotient>
mulx %o0, %g1, %g1
rett %i7 + 8
srlx %g1, 0xa, %o0
New sched_clock():
sethi %hi(0xb9b400), %g1
ldx [ %g1 + 0x340 ], %g1
call %g1
nop
sethi %hi(0xb9b400), %g1
ldx [ %g1 + 0x378 ], %g1
mulx %o0, %g1, %g1
rett %i7 + 8
srlx %g1, 0xa, %o0
Before three loads, now two loads.
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Shannon Nelson <shannon.nelson@oracle.com>
Reviewed-by: Steven Sistare <steven.sistare@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc/kernel/time_64.c b/arch/sparc/kernel/time_64.c
index 98d05de..6724bcb 100644
--- a/arch/sparc/kernel/time_64.c
+++ b/arch/sparc/kernel/time_64.c
@@ -585,6 +585,7 @@
/* This is gets the master TICK_INT timer going. */
static unsigned long sparc64_init_timers(void)
{
+ struct sparc64_tick_ops *ops = NULL;
struct device_node *dp;
unsigned long freq;
@@ -598,16 +599,17 @@
impl = ((ver >> 32) & 0xffff);
if (manuf == 0x17 && impl == 0x13) {
/* Hummingbird, aka Ultra-IIe */
- tick_ops = &hbtick_operations;
+ ops = &hbtick_operations;
freq = of_getintprop_default(dp, "stick-frequency", 0);
} else {
- tick_ops = &tick_operations;
freq = local_cpu_data().clock_tick;
}
} else {
- tick_ops = &stick_operations;
+ ops = &stick_operations;
freq = of_getintprop_default(dp, "stick-frequency", 0);
}
+ if (ops)
+ memcpy(&tick_operations, ops, sizeof(struct sparc64_tick_ops));
return freq;
}
@@ -671,12 +673,12 @@
static int sparc64_next_event(unsigned long delta,
struct clock_event_device *evt)
{
- return tick_ops->add_compare(delta) ? -ETIME : 0;
+ return tick_operations.add_compare(delta) ? -ETIME : 0;
}
static int sparc64_timer_shutdown(struct clock_event_device *evt)
{
- tick_ops->disable_irq();
+ tick_operations.disable_irq();
return 0;
}
@@ -693,7 +695,7 @@
void __irq_entry timer_interrupt(int irq, struct pt_regs *regs)
{
struct pt_regs *old_regs = set_irq_regs(regs);
- unsigned long tick_mask = tick_ops->softint_mask;
+ unsigned long tick_mask = tick_operations.softint_mask;
int cpu = smp_processor_id();
struct clock_event_device *evt = &per_cpu(sparc64_events, cpu);
@@ -728,7 +730,7 @@
: "=r" (pstate)
: "i" (PSTATE_IE));
- tick_ops->init_tick();
+ tick_operations.init_tick();
/* Restore PSTATE_IE. */
__asm__ __volatile__("wrpr %0, 0x0, %%pstate"
@@ -757,9 +759,9 @@
{
unsigned long bclock, now;
- bclock = tick_ops->get_tick();
+ bclock = tick_operations.get_tick();
do {
- now = tick_ops->get_tick();
+ now = tick_operations.get_tick();
} while ((now-bclock) < loops);
}
EXPORT_SYMBOL(__delay);
@@ -772,7 +774,7 @@
static u64 clocksource_tick_read(struct clocksource *cs)
{
- return tick_ops->get_tick();
+ return tick_operations.get_tick();
}
void __init time_init(void)
@@ -784,14 +786,14 @@
timer_ticks_per_nsec_quotient =
clocksource_hz2mult(freq, SPARC64_NSEC_PER_CYC_SHIFT);
- clocksource_tick.name = tick_ops->name;
+ clocksource_tick.name = tick_operations.name;
clocksource_tick.read = clocksource_tick_read;
clocksource_register_hz(&clocksource_tick, freq);
printk("clocksource: mult[%x] shift[%d]\n",
clocksource_tick.mult, clocksource_tick.shift);
- sparc64_clockevent.name = tick_ops->name;
+ sparc64_clockevent.name = tick_operations.name;
clockevents_calc_mult_shift(&sparc64_clockevent, freq, 4);
sparc64_clockevent.max_delta_ns =
@@ -809,7 +811,7 @@
unsigned long long sched_clock(void)
{
- unsigned long ticks = tick_ops->get_tick();
+ unsigned long ticks = tick_operations.get_tick();
return (ticks * timer_ticks_per_nsec_quotient)
>> SPARC64_NSEC_PER_CYC_SHIFT;
@@ -817,6 +819,6 @@
int read_current_timer(unsigned long *timer_val)
{
- *timer_val = tick_ops->get_tick();
+ *timer_val = tick_operations.get_tick();
return 0;
}