18d7f2e76SPhilippe Mathieu-Daudé /*
28d7f2e76SPhilippe Mathieu-Daudé * QEMU System Emulator
38d7f2e76SPhilippe Mathieu-Daudé *
48d7f2e76SPhilippe Mathieu-Daudé * Copyright (c) 2003-2008 Fabrice Bellard
58d7f2e76SPhilippe Mathieu-Daudé *
68d7f2e76SPhilippe Mathieu-Daudé * Permission is hereby granted, free of charge, to any person obtaining a copy
78d7f2e76SPhilippe Mathieu-Daudé * of this software and associated documentation files (the "Software"), to deal
88d7f2e76SPhilippe Mathieu-Daudé * in the Software without restriction, including without limitation the rights
98d7f2e76SPhilippe Mathieu-Daudé * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
108d7f2e76SPhilippe Mathieu-Daudé * copies of the Software, and to permit persons to whom the Software is
118d7f2e76SPhilippe Mathieu-Daudé * furnished to do so, subject to the following conditions:
128d7f2e76SPhilippe Mathieu-Daudé *
138d7f2e76SPhilippe Mathieu-Daudé * The above copyright notice and this permission notice shall be included in
148d7f2e76SPhilippe Mathieu-Daudé * all copies or substantial portions of the Software.
158d7f2e76SPhilippe Mathieu-Daudé *
168d7f2e76SPhilippe Mathieu-Daudé * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
178d7f2e76SPhilippe Mathieu-Daudé * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
188d7f2e76SPhilippe Mathieu-Daudé * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
198d7f2e76SPhilippe Mathieu-Daudé * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
208d7f2e76SPhilippe Mathieu-Daudé * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
218d7f2e76SPhilippe Mathieu-Daudé * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
228d7f2e76SPhilippe Mathieu-Daudé * THE SOFTWARE.
238d7f2e76SPhilippe Mathieu-Daudé */
248d7f2e76SPhilippe Mathieu-Daudé
258d7f2e76SPhilippe Mathieu-Daudé #include "qemu/osdep.h"
268d7f2e76SPhilippe Mathieu-Daudé #include "qemu/thread.h"
278d7f2e76SPhilippe Mathieu-Daudé #include "hw/core/cpu.h"
288d7f2e76SPhilippe Mathieu-Daudé #include "qemu/main-loop.h"
298d7f2e76SPhilippe Mathieu-Daudé #include "sysemu/cpus.h"
308d7f2e76SPhilippe Mathieu-Daudé #include "sysemu/cpu-throttle.h"
318d7f2e76SPhilippe Mathieu-Daudé
328d7f2e76SPhilippe Mathieu-Daudé /* vcpu throttling controls */
338d7f2e76SPhilippe Mathieu-Daudé static QEMUTimer *throttle_timer;
348d7f2e76SPhilippe Mathieu-Daudé static unsigned int throttle_percentage;
358d7f2e76SPhilippe Mathieu-Daudé
368d7f2e76SPhilippe Mathieu-Daudé #define CPU_THROTTLE_PCT_MIN 1
378d7f2e76SPhilippe Mathieu-Daudé #define CPU_THROTTLE_PCT_MAX 99
388d7f2e76SPhilippe Mathieu-Daudé #define CPU_THROTTLE_TIMESLICE_NS 10000000
398d7f2e76SPhilippe Mathieu-Daudé
cpu_throttle_thread(CPUState * cpu,run_on_cpu_data opaque)408d7f2e76SPhilippe Mathieu-Daudé static void cpu_throttle_thread(CPUState *cpu, run_on_cpu_data opaque)
418d7f2e76SPhilippe Mathieu-Daudé {
428d7f2e76SPhilippe Mathieu-Daudé double pct;
438d7f2e76SPhilippe Mathieu-Daudé double throttle_ratio;
448d7f2e76SPhilippe Mathieu-Daudé int64_t sleeptime_ns, endtime_ns;
458d7f2e76SPhilippe Mathieu-Daudé
468d7f2e76SPhilippe Mathieu-Daudé if (!cpu_throttle_get_percentage()) {
478d7f2e76SPhilippe Mathieu-Daudé return;
488d7f2e76SPhilippe Mathieu-Daudé }
498d7f2e76SPhilippe Mathieu-Daudé
508d7f2e76SPhilippe Mathieu-Daudé pct = (double)cpu_throttle_get_percentage() / 100;
518d7f2e76SPhilippe Mathieu-Daudé throttle_ratio = pct / (1 - pct);
528d7f2e76SPhilippe Mathieu-Daudé /* Add 1ns to fix double's rounding error (like 0.9999999...) */
538d7f2e76SPhilippe Mathieu-Daudé sleeptime_ns = (int64_t)(throttle_ratio * CPU_THROTTLE_TIMESLICE_NS + 1);
548d7f2e76SPhilippe Mathieu-Daudé endtime_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + sleeptime_ns;
558d7f2e76SPhilippe Mathieu-Daudé while (sleeptime_ns > 0 && !cpu->stop) {
568d7f2e76SPhilippe Mathieu-Daudé if (sleeptime_ns > SCALE_MS) {
57*7c754c78SStefan Hajnoczi qemu_cond_timedwait_bql(cpu->halt_cond,
588d7f2e76SPhilippe Mathieu-Daudé sleeptime_ns / SCALE_MS);
598d7f2e76SPhilippe Mathieu-Daudé } else {
60195801d7SStefan Hajnoczi bql_unlock();
618d7f2e76SPhilippe Mathieu-Daudé g_usleep(sleeptime_ns / SCALE_US);
62195801d7SStefan Hajnoczi bql_lock();
638d7f2e76SPhilippe Mathieu-Daudé }
648d7f2e76SPhilippe Mathieu-Daudé sleeptime_ns = endtime_ns - qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
658d7f2e76SPhilippe Mathieu-Daudé }
668d7f2e76SPhilippe Mathieu-Daudé qatomic_set(&cpu->throttle_thread_scheduled, 0);
678d7f2e76SPhilippe Mathieu-Daudé }
688d7f2e76SPhilippe Mathieu-Daudé
cpu_throttle_timer_tick(void * opaque)698d7f2e76SPhilippe Mathieu-Daudé static void cpu_throttle_timer_tick(void *opaque)
708d7f2e76SPhilippe Mathieu-Daudé {
718d7f2e76SPhilippe Mathieu-Daudé CPUState *cpu;
728d7f2e76SPhilippe Mathieu-Daudé double pct;
738d7f2e76SPhilippe Mathieu-Daudé
748d7f2e76SPhilippe Mathieu-Daudé /* Stop the timer if needed */
758d7f2e76SPhilippe Mathieu-Daudé if (!cpu_throttle_get_percentage()) {
768d7f2e76SPhilippe Mathieu-Daudé return;
778d7f2e76SPhilippe Mathieu-Daudé }
788d7f2e76SPhilippe Mathieu-Daudé CPU_FOREACH(cpu) {
798d7f2e76SPhilippe Mathieu-Daudé if (!qatomic_xchg(&cpu->throttle_thread_scheduled, 1)) {
808d7f2e76SPhilippe Mathieu-Daudé async_run_on_cpu(cpu, cpu_throttle_thread,
818d7f2e76SPhilippe Mathieu-Daudé RUN_ON_CPU_NULL);
828d7f2e76SPhilippe Mathieu-Daudé }
838d7f2e76SPhilippe Mathieu-Daudé }
848d7f2e76SPhilippe Mathieu-Daudé
858d7f2e76SPhilippe Mathieu-Daudé pct = (double)cpu_throttle_get_percentage() / 100;
868d7f2e76SPhilippe Mathieu-Daudé timer_mod(throttle_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT) +
878d7f2e76SPhilippe Mathieu-Daudé CPU_THROTTLE_TIMESLICE_NS / (1 - pct));
888d7f2e76SPhilippe Mathieu-Daudé }
898d7f2e76SPhilippe Mathieu-Daudé
cpu_throttle_set(int new_throttle_pct)908d7f2e76SPhilippe Mathieu-Daudé void cpu_throttle_set(int new_throttle_pct)
918d7f2e76SPhilippe Mathieu-Daudé {
928d7f2e76SPhilippe Mathieu-Daudé /*
938d7f2e76SPhilippe Mathieu-Daudé * boolean to store whether throttle is already active or not,
948d7f2e76SPhilippe Mathieu-Daudé * before modifying throttle_percentage
958d7f2e76SPhilippe Mathieu-Daudé */
968d7f2e76SPhilippe Mathieu-Daudé bool throttle_active = cpu_throttle_active();
978d7f2e76SPhilippe Mathieu-Daudé
988d7f2e76SPhilippe Mathieu-Daudé /* Ensure throttle percentage is within valid range */
998d7f2e76SPhilippe Mathieu-Daudé new_throttle_pct = MIN(new_throttle_pct, CPU_THROTTLE_PCT_MAX);
1008d7f2e76SPhilippe Mathieu-Daudé new_throttle_pct = MAX(new_throttle_pct, CPU_THROTTLE_PCT_MIN);
1018d7f2e76SPhilippe Mathieu-Daudé
1028d7f2e76SPhilippe Mathieu-Daudé qatomic_set(&throttle_percentage, new_throttle_pct);
1038d7f2e76SPhilippe Mathieu-Daudé
1048d7f2e76SPhilippe Mathieu-Daudé if (!throttle_active) {
1058d7f2e76SPhilippe Mathieu-Daudé cpu_throttle_timer_tick(NULL);
1068d7f2e76SPhilippe Mathieu-Daudé }
1078d7f2e76SPhilippe Mathieu-Daudé }
1088d7f2e76SPhilippe Mathieu-Daudé
cpu_throttle_stop(void)1098d7f2e76SPhilippe Mathieu-Daudé void cpu_throttle_stop(void)
1108d7f2e76SPhilippe Mathieu-Daudé {
1118d7f2e76SPhilippe Mathieu-Daudé qatomic_set(&throttle_percentage, 0);
1128d7f2e76SPhilippe Mathieu-Daudé }
1138d7f2e76SPhilippe Mathieu-Daudé
cpu_throttle_active(void)1148d7f2e76SPhilippe Mathieu-Daudé bool cpu_throttle_active(void)
1158d7f2e76SPhilippe Mathieu-Daudé {
1168d7f2e76SPhilippe Mathieu-Daudé return (cpu_throttle_get_percentage() != 0);
1178d7f2e76SPhilippe Mathieu-Daudé }
1188d7f2e76SPhilippe Mathieu-Daudé
cpu_throttle_get_percentage(void)1198d7f2e76SPhilippe Mathieu-Daudé int cpu_throttle_get_percentage(void)
1208d7f2e76SPhilippe Mathieu-Daudé {
1218d7f2e76SPhilippe Mathieu-Daudé return qatomic_read(&throttle_percentage);
1228d7f2e76SPhilippe Mathieu-Daudé }
1238d7f2e76SPhilippe Mathieu-Daudé
cpu_throttle_init(void)1248d7f2e76SPhilippe Mathieu-Daudé void cpu_throttle_init(void)
1258d7f2e76SPhilippe Mathieu-Daudé {
1268d7f2e76SPhilippe Mathieu-Daudé throttle_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL_RT,
1278d7f2e76SPhilippe Mathieu-Daudé cpu_throttle_timer_tick, NULL);
1288d7f2e76SPhilippe Mathieu-Daudé }
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