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x86/timer: increase readability in check_ticks()

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This commit is contained in:
daniel-k 2016-08-29 12:39:26 +02:00
parent fb2d9f83c8
commit 047dbfd56f
1 changed files with 9 additions and 7 deletions
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16
hermit/arch/x86/kernel/timer.c
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@ -54,13 +54,15 @@ void check_ticks(void)
if (!cpu_freq)
return;
uint64_t curr_rdtsc = get_rdtsc();
uint64_t diff;
const uint64_t curr_rdtsc = has_rdtscp() ? rdtscp(NULL) : rdtsc();
rmb();
diff = ((curr_rdtsc - per_core(last_rdtsc)) * (uint64_t)TIMER_FREQ) / (1000000ULL*(uint64_t)get_cpu_frequency());
if (diff > 0) {
set_per_core(timer_ticks, per_core(timer_ticks) + diff);
const uint64_t diff_cycles = curr_rdtsc - per_core(last_rdtsc);
const uint64_t cpu_freq_hz = 1000000ULL * (uint64_t) get_cpu_frequency();
const uint64_t diff_ticks = (diff_cycles * (uint64_t) TIMER_FREQ) / cpu_freq_hz;
if (diff_ticks > 0) {
set_per_core(timer_ticks, per_core(timer_ticks) + diff_ticks);
set_per_core(last_rdtsc, curr_rdtsc);
rmb();
}
@ -187,7 +189,7 @@ int timer_init(void)
irq_install_handler(121, wakeup_handler);
#ifdef DYNAMIC_TICKS
boot_tsc = get_rdtsc();
boot_tsc = has_rdtscp() ? rdtscp(NULL) : rdtsc();
set_per_core(last_rdtsc, boot_tsc);
#endif