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protect tick counter by a lock

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every core should determine the tick counter => lock is required to
protect the counter
This commit is contained in:
Stefan Lankes 2015-08-28 17:36:11 +02:00
parent 68bac65eef
commit 1c09232784
1 changed files with 32 additions and 21 deletions
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53
hermit/arch/x86/kernel/timer.c
View file

@ -31,6 +31,7 @@
#include <hermit/time.h>
#include <hermit/tasks.h>
#include <hermit/errno.h>
#include <hermit/spinlock.h>
#include <asm/irq.h>
#include <asm/irqflags.h>
#include <asm/io.h>
@ -46,6 +47,10 @@ extern int32_t boot_processor;
static int8_t use_tickless = 0;
static uint64_t last_rdtsc = 0;
#if MAX_CORES > 1
static spinlock_irqsave_t ticks_lock = SPINLOCK_IRQSAVE_INIT;
#endif
void start_tickless(void)
{
use_tickless = 1;
@ -68,33 +73,37 @@ void check_ticks(void)
return;
#if MAX_CORES > 1
if (CORE_ID == boot_processor)
spinlock_irqsave_lock(&ticks_lock);
#endif
{
if (has_rdtscp()){
uint64_t curr_rdtsc = rdtscp(NULL);
uint64_t diff;
rmb();
diff = ((curr_rdtsc - last_rdtsc) * (uint64_t)TIMER_FREQ) / (1000000ULL*(uint64_t)get_cpu_frequency());
if (diff > 0) {
timer_ticks += diff;
last_rdtsc = curr_rdtsc;
rmb();
}
} else {
uint64_t curr_rdtsc = rdtsc();
uint64_t diff;
if (has_rdtscp()){
uint64_t curr_rdtsc = rdtscp(NULL);
uint64_t diff;
rmb();
diff = ((curr_rdtsc - last_rdtsc) * (uint64_t)TIMER_FREQ) / (1000000ULL*(uint64_t)get_cpu_frequency());
if (diff > 0) {
timer_ticks += diff;
last_rdtsc = curr_rdtsc;
rmb();
}
} else {
uint64_t curr_rdtsc = rdtsc();
uint64_t diff;
rmb();
diff = ((curr_rdtsc - last_rdtsc) * (uint64_t)TIMER_FREQ) / (1000000ULL*(uint64_t)get_cpu_frequency());
if (diff > 0) {
timer_ticks += diff;
last_rdtsc = curr_rdtsc;
rmb();
diff = ((curr_rdtsc - last_rdtsc) * (uint64_t)TIMER_FREQ) / (1000000ULL*(uint64_t)get_cpu_frequency());
if (diff > 0) {
timer_ticks += diff;
last_rdtsc = curr_rdtsc;
rmb();
}
}
}
#if MAX_CORES > 1
spinlock_irqsave_unlock(&ticks_lock);
#endif
}
uint64_t get_clock_tick(void)
@ -109,7 +118,9 @@ uint64_t get_clock_tick(void)
*/
static void timer_handler(struct state *s)
{
#if MAX_CORES > 1
if (CORE_ID == boot_processor)
#endif
/* Increment our 'tick counter' */
timer_ticks++;