0a55e63413
- two CPUs can issue IPI to each other now without any hazzard - we must be able to handle synchronous scheduling IPIs from other CPUs when we are waiting for attention from another one. Otherwise we might livelock. - necessary barriers to prevent reordering
366 lines
8.4 KiB
C
366 lines
8.4 KiB
C
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/* i386-specific clock functions. */
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#include <machine/ports.h>
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#include <minix/portio.h>
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#include "kernel/kernel.h"
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#include "kernel/clock.h"
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#include "kernel/proc.h"
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#include "kernel/interrupt.h"
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#include <minix/u64.h>
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#include "glo.h"
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#include "profile.h"
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#ifdef USE_APIC
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#include "apic.h"
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#endif
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#include "spinlock.h"
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#ifdef CONFIG_SMP
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#include "kernel/smp.h"
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#endif
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#define CLOCK_ACK_BIT 0x80 /* PS/2 clock interrupt acknowledge bit */
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/* Clock parameters. */
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#define COUNTER_FREQ (2*TIMER_FREQ) /* counter frequency using square wave */
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#define LATCH_COUNT 0x00 /* cc00xxxx, c = channel, x = any */
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#define SQUARE_WAVE 0x36 /* ccaammmb, a = access, m = mode, b = BCD */
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/* 11x11, 11 = LSB then MSB, x11 = sq wave */
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#define TIMER_FREQ 1193182 /* clock frequency for timer in PC and AT */
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#define TIMER_COUNT(freq) (TIMER_FREQ/(freq)) /* initial value for counter*/
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PRIVATE irq_hook_t pic_timer_hook; /* interrupt handler hook */
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PRIVATE unsigned probe_ticks;
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PRIVATE u64_t tsc0, tsc1;
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#define PROBE_TICKS (system_hz / 10)
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PRIVATE unsigned tsc_per_ms[CONFIG_MAX_CPUS];
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/*===========================================================================*
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* init_8235A_timer *
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*===========================================================================*/
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PUBLIC int init_8253A_timer(const unsigned freq)
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{
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/* Initialize channel 0 of the 8253A timer to, e.g., 60 Hz,
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* and register the CLOCK task's interrupt handler to be run
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* on every clock tick.
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*/
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outb(TIMER_MODE, SQUARE_WAVE); /* run continuously */
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outb(TIMER0, (TIMER_COUNT(freq) & 0xff)); /* timer low byte */
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outb(TIMER0, TIMER_COUNT(freq) >> 8); /* timer high byte */
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return OK;
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}
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/*===========================================================================*
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* stop_8235A_timer *
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*===========================================================================*/
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PUBLIC void stop_8253A_timer(void)
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{
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/* Reset the clock to the BIOS rate. (For rebooting.) */
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outb(TIMER_MODE, 0x36);
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outb(TIMER0, 0);
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outb(TIMER0, 0);
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}
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PRIVATE int calib_cpu_handler(irq_hook_t * UNUSED(hook))
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{
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u64_t tsc;
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probe_ticks++;
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read_tsc_64(&tsc);
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if (probe_ticks == 1) {
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tsc0 = tsc;
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}
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else if (probe_ticks == PROBE_TICKS) {
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tsc1 = tsc;
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}
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/* just in case we are in an SMP single cpu fallback mode */
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BKL_UNLOCK();
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return 1;
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}
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PRIVATE void estimate_cpu_freq(void)
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{
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u64_t tsc_delta;
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u64_t cpu_freq;
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irq_hook_t calib_cpu;
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/* set the probe, we use the legacy timer, IRQ 0 */
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put_irq_handler(&calib_cpu, CLOCK_IRQ, calib_cpu_handler);
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/* just in case we are in an SMP single cpu fallback mode */
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BKL_UNLOCK();
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/* set the PIC timer to get some time */
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intr_enable();
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/* loop for some time to get a sample */
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while(probe_ticks < PROBE_TICKS) {
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intr_enable();
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}
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intr_disable();
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/* just in case we are in an SMP single cpu fallback mode */
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BKL_LOCK();
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/* remove the probe */
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rm_irq_handler(&calib_cpu);
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tsc_delta = sub64(tsc1, tsc0);
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cpu_freq = mul64(div64u64(tsc_delta, PROBE_TICKS - 1), make64(system_hz, 0));
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cpu_set_freq(cpuid, cpu_freq);
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cpu_info[cpuid].freq = div64u(cpu_freq, 1000000);
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BOOT_VERBOSE(cpu_print_freq(cpuid));
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}
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PUBLIC int init_local_timer(unsigned freq)
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{
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#ifdef USE_APIC
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/* if we know the address, lapic is enabled and we should use it */
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if (lapic_addr) {
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unsigned cpu = cpuid;
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tsc_per_ms[cpu] = div64u(cpu_get_freq(cpu), 1000);
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lapic_set_timer_one_shot(1000000/system_hz);
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} else
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{
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BOOT_VERBOSE(printf("Initiating legacy i8253 timer\n"));
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#else
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{
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#endif
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init_8253A_timer(freq);
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estimate_cpu_freq();
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/* always only 1 cpu in the system */
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tsc_per_ms[0] = div64u(cpu_get_freq(0), 1000);
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}
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return 0;
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}
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PUBLIC void stop_local_timer(void)
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{
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#ifdef USE_APIC
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if (lapic_addr) {
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lapic_stop_timer();
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apic_eoi();
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} else
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#endif
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{
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stop_8253A_timer();
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}
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}
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PUBLIC void restart_local_timer(void)
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{
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#ifdef USE_APIC
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if (lapic_addr) {
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lapic_restart_timer();
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}
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#endif
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}
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PUBLIC int register_local_timer_handler(const irq_handler_t handler)
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{
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#ifdef USE_APIC
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if (lapic_addr) {
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/* Using APIC, it is configured in apic_idt_init() */
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BOOT_VERBOSE(printf("Using LAPIC timer as tick source\n"));
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} else
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#endif
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{
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/* Using PIC, Initialize the CLOCK's interrupt hook. */
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pic_timer_hook.proc_nr_e = NONE;
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pic_timer_hook.irq = CLOCK_IRQ;
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put_irq_handler(&pic_timer_hook, CLOCK_IRQ, handler);
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}
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return 0;
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}
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PUBLIC void cycles_accounting_init(void)
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{
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#ifdef CONFIG_SMP
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unsigned cpu = cpuid;
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#endif
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read_tsc_64(get_cpu_var_ptr(cpu, tsc_ctr_switch));
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make_zero64(get_cpu_var(cpu, cpu_last_tsc));
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make_zero64(get_cpu_var(cpu, cpu_last_idle));
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}
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PUBLIC void context_stop(struct proc * p)
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{
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u64_t tsc, tsc_delta;
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u64_t * __tsc_ctr_switch = get_cpulocal_var_ptr(tsc_ctr_switch);
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#ifdef CONFIG_SMP
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unsigned cpu = cpuid;
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/*
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* This function is called only if we switch from kernel to user or idle
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* or back. Therefore this is a perfect location to place the big kernel
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* lock which will hopefully disappear soon.
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*
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* If we stop accounting for KERNEL we must unlock the BKL. If account
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* for IDLE we must not hold the lock
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*/
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if (p == proc_addr(KERNEL)) {
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u64_t tmp;
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read_tsc_64(&tsc);
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tmp = sub64(tsc, *__tsc_ctr_switch);
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kernel_ticks[cpu] = add64(kernel_ticks[cpu], tmp);
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p->p_cycles = add64(p->p_cycles, tmp);
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BKL_UNLOCK();
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} else {
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u64_t bkl_tsc;
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atomic_t succ;
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read_tsc_64(&bkl_tsc);
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/* this only gives a good estimate */
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succ = big_kernel_lock.val;
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BKL_LOCK();
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read_tsc_64(&tsc);
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bkl_ticks[cpu] = add64(bkl_ticks[cpu], sub64(tsc, bkl_tsc));
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bkl_tries[cpu]++;
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bkl_succ[cpu] += !(!(succ == 0));
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p->p_cycles = add64(p->p_cycles, sub64(tsc, *__tsc_ctr_switch));
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#ifdef CONFIG_SMP
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/*
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* Since at the time we got a scheduling IPI we might have been
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* waiting for BKL already, we may miss it due to a similar IPI to
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* the cpu which is already waiting for us to handle its. This
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* results in a live-lock of these two cpus.
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*
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* Therefore we always check if there is one pending and if so,
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* we handle it straight away so the other cpu can continue and
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* we do not deadlock.
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*/
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smp_sched_handler();
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#endif
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}
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#else
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read_tsc_64(&tsc);
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p->p_cycles = add64(p->p_cycles, sub64(tsc, *__tsc_ctr_switch));
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#endif
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tsc_delta = sub64(tsc, *__tsc_ctr_switch);
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if(kbill_ipc) {
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kbill_ipc->p_kipc_cycles =
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add64(kbill_ipc->p_kipc_cycles, tsc_delta);
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kbill_ipc = NULL;
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}
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if(kbill_kcall) {
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kbill_kcall->p_kcall_cycles =
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add64(kbill_kcall->p_kcall_cycles, tsc_delta);
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kbill_kcall = NULL;
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}
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/*
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* deduct the just consumed cpu cycles from the cpu time left for this
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* process during its current quantum. Skip IDLE and other pseudo kernel
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* tasks
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*/
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if (p->p_endpoint >= 0) {
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#if DEBUG_RACE
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make_zero64(p->p_cpu_time_left);
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#else
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/* if (tsc_delta < p->p_cpu_time_left) in 64bit */
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if (ex64hi(tsc_delta) < ex64hi(p->p_cpu_time_left) ||
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(ex64hi(tsc_delta) == ex64hi(p->p_cpu_time_left) &&
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ex64lo(tsc_delta) < ex64lo(p->p_cpu_time_left)))
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p->p_cpu_time_left = sub64(p->p_cpu_time_left, tsc_delta);
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else {
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make_zero64(p->p_cpu_time_left);
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}
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#endif
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}
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*__tsc_ctr_switch = tsc;
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}
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PUBLIC void context_stop_idle(void)
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{
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int is_idle;
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#ifdef CONFIG_SMP
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unsigned cpu = cpuid;
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#endif
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is_idle = get_cpu_var(cpu, cpu_is_idle);
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get_cpu_var(cpu, cpu_is_idle) = 0;
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context_stop(get_cpulocal_var_ptr(idle_proc));
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if (is_idle)
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restart_local_timer();
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#if SPROFILE
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if (sprofiling)
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get_cpulocal_var(idle_interrupted) = 1;
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#endif
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}
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PUBLIC u64_t ms_2_cpu_time(unsigned ms)
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{
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return mul64u(tsc_per_ms[cpuid], ms);
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}
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PUBLIC unsigned cpu_time_2_ms(u64_t cpu_time)
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{
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return div64u(cpu_time, tsc_per_ms[cpuid]);
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}
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PUBLIC short cpu_load(void)
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{
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u64_t current_tsc, *current_idle;
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u64_t tsc_delta, idle_delta, busy;
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struct proc *idle;
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short load;
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#ifdef CONFIG_SMP
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unsigned cpu = cpuid;
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#endif
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u64_t *last_tsc, *last_idle;
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last_tsc = get_cpu_var_ptr(cpu, cpu_last_tsc);
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last_idle = get_cpu_var_ptr(cpu, cpu_last_idle);
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idle = get_cpu_var_ptr(cpu, idle_proc);;
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read_tsc_64(¤t_tsc);
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current_idle = &idle->p_cycles; /* ptr to idle proc */
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/* calculate load since last cpu_load invocation */
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if (!is_zero64(*last_tsc)) {
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tsc_delta = sub64(current_tsc, *last_tsc);
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idle_delta = sub64(*current_idle, *last_idle);
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busy = sub64(tsc_delta, idle_delta);
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busy = mul64(busy, make64(100, 0));
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load = ex64lo(div64(busy, tsc_delta));
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if (load > 100)
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load = 100;
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} else
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load = 0;
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*last_tsc = current_tsc;
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*last_idle = *current_idle;
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return load;
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}
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