52ac968ab2
When VM is configured with huge memory, the current throttle logic doesn't look like to scale, because migration_trigger_throttle() is only called for each iteration, so it won't be invoked for a long time if one iteration can take a long time. The periodic dirty sync aims to fix the above issue by synchronizing the ramblock from remote dirty bitmap and, when necessary, triggering the CPU throttle multiple times during a long iteration. This is a trade-off between synchronization overhead and CPU throttle impact. Signed-off-by: Hyman Huang <yong.huang@smartx.com> Reviewed-by: Fabiano Rosas <farosas@suse.de> Link: https://lore.kernel.org/r/f61f1b3653f2acf026901103e1c73d157d38b08f.1729146786.git.yong.huang@smartx.com [peterx: make prev_cnt global, and reset for each migration] Signed-off-by: Peter Xu <peterx@redhat.com>
83 lines
2.2 KiB
C
83 lines
2.2 KiB
C
/*
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* Copyright (c) 2012 SUSE LINUX Products GmbH
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see
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* <http://www.gnu.org/licenses/gpl-2.0.html>
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*/
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#ifndef SYSEMU_CPU_THROTTLE_H
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#define SYSEMU_CPU_THROTTLE_H
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#include "qemu/timer.h"
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/**
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* cpu_throttle_init:
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*
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* Initialize the CPU throttling API.
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*/
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void cpu_throttle_init(void);
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/**
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* cpu_throttle_set:
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* @new_throttle_pct: Percent of sleep time. Valid range is 1 to 99.
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*
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* Throttles all vcpus by forcing them to sleep for the given percentage of
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* time. A throttle_percentage of 25 corresponds to a 75% duty cycle roughly.
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* (example: 10ms sleep for every 30ms awake).
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*
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* cpu_throttle_set can be called as needed to adjust new_throttle_pct.
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* Once the throttling starts, it will remain in effect until cpu_throttle_stop
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* is called.
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*/
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void cpu_throttle_set(int new_throttle_pct);
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/**
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* cpu_throttle_stop:
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*
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* Stops the vcpu throttling started by cpu_throttle_set.
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*/
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void cpu_throttle_stop(void);
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/**
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* cpu_throttle_active:
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*
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* Returns: %true if the vcpus are currently being throttled, %false otherwise.
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*/
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bool cpu_throttle_active(void);
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/**
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* cpu_throttle_get_percentage:
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*
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* Returns the vcpu throttle percentage. See cpu_throttle_set for details.
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*
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* Returns: The throttle percentage in range 1 to 99.
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*/
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int cpu_throttle_get_percentage(void);
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/**
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* cpu_throttle_dirty_sync_timer_tick:
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*
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* Dirty sync timer hook.
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*/
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void cpu_throttle_dirty_sync_timer_tick(void *opaque);
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/**
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* cpu_throttle_dirty_sync_timer:
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*
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* Start or stop the dirty sync timer.
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*/
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void cpu_throttle_dirty_sync_timer(bool enable);
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#endif /* SYSEMU_CPU_THROTTLE_H */
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