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  */
  29 void 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  */
  43 void 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  */
  50 void cpu_throttle_stop(void);
  51
  52 /**
  53  * cpu_throttle_active:
  54  *
  55  * Returns: %true if the vcpus are currently being throttled, %false otherwise.
  56  */
  57 bool 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  */
  66 int cpu_throttle_get_percentage(void);
  67
  68 #endif /* SYSEMU_CPU_THROTTLE_H */