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| author | Stefan Hajnoczi <stefanha@redhat.com> | 2023-10-09 10:11:17 -0400 |
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| committer | Stefan Hajnoczi <stefanha@redhat.com> | 2023-10-09 10:11:18 -0400 |
| commit | 1527c6b6fa6c6775523287e33f78b41afc7ba46c (patch) | |
| tree | e245ed1f0f1856b800b391e22da9d09b21950540 /system/cpu-throttle.c | |
| parent | f7294103560260ff09ffdf316cf6ba6d4e368d85 (diff) | |
| parent | 912eef205ae9ccfd477c343a51a7c2dcfae2ba43 (diff) | |
| download | focaccia-qemu-1527c6b6fa6c6775523287e33f78b41afc7ba46c.tar.gz focaccia-qemu-1527c6b6fa6c6775523287e33f78b41afc7ba46c.zip | |
Merge tag 'for-upstream' of https://gitlab.com/bonzini/qemu into staging
* util/log: re-allow switching away from stderr log file * finish audio configuration rework * cleanup HVF stubs * remove more mentions of softmmu # -----BEGIN PGP SIGNATURE----- # # iQFIBAABCAAyFiEE8TM4V0tmI4mGbHaCv/vSX3jHroMFAmUi/kIUHHBib256aW5p # QHJlZGhhdC5jb20ACgkQv/vSX3jHroOXWwf/YW16QMzqdAPVHYRf9NcCneRF16El # t3lEod0q0sHhchPbh9e04aKbh+oBNeWu9sFyTl11Fwsi+DGmp/b28ziva75/4rfd # h5N9aX/z2jwPqy93IwPDu3soKXCCgTK+ywtD/5GLQwBGqxs7W2xUEEb7eCnVefHa # zwL3MOUqPICeqOnR1TNw9k3N3veF04D+rmchTwbAjAmx1f8EI+mK9VlGK9V8TUjP # 3HjpZYJluc0a92lR5VONJ7V25QfttsjLysTgpFwVAQPS6Frzatc/hWclfLYgw9vl # 2Irk83FV8gXPRl0XKNcqSDsv6h/yGP6TDFIB8QwRSRGBqIQi5aOlfBJzsQ== # =qbm7 # -----END PGP SIGNATURE----- # gpg: Signature made Sun 08 Oct 2023 15:08:50 EDT # gpg: using RSA key F13338574B662389866C7682BFFBD25F78C7AE83 # gpg: issuer "pbonzini@redhat.com" # gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>" [full] # gpg: aka "Paolo Bonzini <pbonzini@redhat.com>" [full] # Primary key fingerprint: 46F5 9FBD 57D6 12E7 BFD4 E2F7 7E15 100C CD36 69B1 # Subkey fingerprint: F133 3857 4B66 2389 866C 7682 BFFB D25F 78C7 AE83 * tag 'for-upstream' of https://gitlab.com/bonzini/qemu: (25 commits) audio, qtest: get rid of QEMU_AUDIO_DRV audio: reintroduce default audio backend for VNC audio: do not use first -audiodev as default audio device audio: extend -audio to allow creating a default backend audio: extract audio_define_default audio: disable default backends if -audio/-audiodev is used audio: error hints need a trailing \n cutils: squelch compiler warnings with custom paths configure: change $softmmu to $system system: Rename softmmu/ directory as system/ meson: Rename target_softmmu_arch -> target_system_arch meson: Rename softmmu_mods -> system_mods target/i386: Rename i386_softmmu_kvm_ss -> i386_kvm_ss semihosting: Rename softmmu_FOO_user() -> uaccess_FOO_user() gdbstub: Rename 'softmmu' -> 'system' accel: Rename accel_softmmu* -> accel_system* tcg: Correct invalid mentions of 'softmmu' by 'system-mode' fuzz: Correct invalid mentions of 'softmmu' by 'system' cpu: Correct invalid mentions of 'softmmu' by 'system-mode' travis-ci: Correct invalid mentions of 'softmmu' by 'system' ... Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'system/cpu-throttle.c')
| -rw-r--r-- | system/cpu-throttle.c | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/system/cpu-throttle.c b/system/cpu-throttle.c new file mode 100644 index 0000000000..d9bb30a223 --- /dev/null +++ b/system/cpu-throttle.c @@ -0,0 +1,128 @@ +/* + * QEMU System Emulator + * + * Copyright (c) 2003-2008 Fabrice Bellard + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include "qemu/osdep.h" +#include "qemu/thread.h" +#include "hw/core/cpu.h" +#include "qemu/main-loop.h" +#include "sysemu/cpus.h" +#include "sysemu/cpu-throttle.h" + +/* vcpu throttling controls */ +static QEMUTimer *throttle_timer; +static unsigned int throttle_percentage; + +#define CPU_THROTTLE_PCT_MIN 1 +#define CPU_THROTTLE_PCT_MAX 99 +#define CPU_THROTTLE_TIMESLICE_NS 10000000 + +static void cpu_throttle_thread(CPUState *cpu, run_on_cpu_data opaque) +{ + double pct; + double throttle_ratio; + int64_t sleeptime_ns, endtime_ns; + + if (!cpu_throttle_get_percentage()) { + return; + } + + pct = (double)cpu_throttle_get_percentage() / 100; + throttle_ratio = pct / (1 - pct); + /* Add 1ns to fix double's rounding error (like 0.9999999...) */ + sleeptime_ns = (int64_t)(throttle_ratio * CPU_THROTTLE_TIMESLICE_NS + 1); + endtime_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + sleeptime_ns; + while (sleeptime_ns > 0 && !cpu->stop) { + if (sleeptime_ns > SCALE_MS) { + qemu_cond_timedwait_iothread(cpu->halt_cond, + sleeptime_ns / SCALE_MS); + } else { + qemu_mutex_unlock_iothread(); + g_usleep(sleeptime_ns / SCALE_US); + qemu_mutex_lock_iothread(); + } + sleeptime_ns = endtime_ns - qemu_clock_get_ns(QEMU_CLOCK_REALTIME); + } + qatomic_set(&cpu->throttle_thread_scheduled, 0); +} + +static void cpu_throttle_timer_tick(void *opaque) +{ + CPUState *cpu; + double pct; + + /* Stop the timer if needed */ + if (!cpu_throttle_get_percentage()) { + return; + } + CPU_FOREACH(cpu) { + if (!qatomic_xchg(&cpu->throttle_thread_scheduled, 1)) { + async_run_on_cpu(cpu, cpu_throttle_thread, + RUN_ON_CPU_NULL); + } + } + + pct = (double)cpu_throttle_get_percentage() / 100; + timer_mod(throttle_timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL_RT) + + CPU_THROTTLE_TIMESLICE_NS / (1 - pct)); +} + +void cpu_throttle_set(int new_throttle_pct) +{ + /* + * boolean to store whether throttle is already active or not, + * before modifying throttle_percentage + */ + bool throttle_active = cpu_throttle_active(); + + /* Ensure throttle percentage is within valid range */ + new_throttle_pct = MIN(new_throttle_pct, CPU_THROTTLE_PCT_MAX); + new_throttle_pct = MAX(new_throttle_pct, CPU_THROTTLE_PCT_MIN); + + qatomic_set(&throttle_percentage, new_throttle_pct); + + if (!throttle_active) { + cpu_throttle_timer_tick(NULL); + } +} + +void cpu_throttle_stop(void) +{ + qatomic_set(&throttle_percentage, 0); +} + +bool cpu_throttle_active(void) +{ + return (cpu_throttle_get_percentage() != 0); +} + +int cpu_throttle_get_percentage(void) +{ + return qatomic_read(&throttle_percentage); +} + +void cpu_throttle_init(void) +{ + throttle_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL_RT, + cpu_throttle_timer_tick, NULL); +} |