LXR qemu/include/sysemu/cpu-throttle.h

   1/*
   2 * Copyright (c) 2012 SUSE LINUX Products GmbH
   3 *
   4 * This program is free software; you can redistribute it and/or
   5 * modify it under the terms of the GNU General Public License
   6 * as published by the Free Software Foundation; either version 2
   7 * of the License, or (at your option) any later version.
   8 *
   9 * This program is distributed in the hope that it will be useful,
  10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 * GNU General Public License for more details.
  13 *
  14 * You should have received a copy of the GNU General Public License
  15 * along with this program; if not, see
  16 * <http://www.gnu.org/licenses/gpl-2.0.html>
  17 */
  18
  19#ifndef SYSEMU_CPU_THROTTLE_H
  20#define SYSEMU_CPU_THROTTLE_H
  21
  22#include "qemu/timer.h"
  23
  24/**
  25 * cpu_throttle_init:
  26 *
  27 * Initialize the CPU throttling API.
  28 */
  29void cpu_throttle_init(void);
  30
  31/**
  32 * cpu_throttle_set:
  33 * @new_throttle_pct: Percent of sleep time. Valid range is 1 to 99.
  34 *
  35 * Throttles all vcpus by forcing them to sleep for the given percentage of
  36 * time. A throttle_percentage of 25 corresponds to a 75% duty cycle roughly.
  37 * (example: 10ms sleep for every 30ms awake).
  38 *
  39 * cpu_throttle_set can be called as needed to adjust new_throttle_pct.
  40 * Once the throttling starts, it will remain in effect until cpu_throttle_stop
  41 * is called.
  42 */
  43void cpu_throttle_set(int new_throttle_pct);
  44
  45/**
  46 * cpu_throttle_stop:
  47 *
  48 * Stops the vcpu throttling started by cpu_throttle_set.
  49 */
  50void cpu_throttle_stop(void);
  51
  52/**
  53 * cpu_throttle_active:
  54 *
  55 * Returns: %true if the vcpus are currently being throttled, %false otherwise.
  56 */
  57bool cpu_throttle_active(void);
  58
  59/**
  60 * cpu_throttle_get_percentage:
  61 *
  62 * Returns the vcpu throttle percentage. See cpu_throttle_set for details.
  63 *
  64 * Returns: The throttle percentage in range 1 to 99.
  65 */
  66int cpu_throttle_get_percentage(void);
  67
  68#endif /* SYSEMU_CPU_THROTTLE_H */
  69