224 lines
6.9 KiB
C
224 lines
6.9 KiB
C
/************************************************************************
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* sched/sched_processtimer.c
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*
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* Copyright (C) 2007, 2009, 2014 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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************************************************************************/
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/************************************************************************
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* Included Files
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************************************************************************/
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#include <nuttx/config.h>
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#include <nuttx/compiler.h>
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#include <time.h>
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#if CONFIG_RR_INTERVAL > 0
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# include <sched.h>
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# include <nuttx/arch.h>
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#endif
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#include "os_internal.h"
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#include "wd_internal.h"
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#include "clock_internal.h"
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/************************************************************************
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* Pre-processor Definitions
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************************************************************************/
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#ifndef CONFIG_SCHED_CPULOAD_TIMECONSTANT
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# define CONFIG_SCHED_CPULOAD_TIMECONSTANT 2
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#endif
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/************************************************************************
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* Private Type Declarations
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************************************************************************/
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/************************************************************************
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* Public Variables
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************************************************************************/
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/************************************************************************
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* Private Variables
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************************************************************************/
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/************************************************************************
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* Private Functions
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************************************************************************/
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/************************************************************************
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* Name: sched_process_timeslice
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*
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* Description:
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* Check if the currently executing task has exceeded its time slice.
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*
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* Inputs:
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* None
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*
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* Return Value:
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* None
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*
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************************************************************************/
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#if CONFIG_RR_INTERVAL > 0
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static inline void sched_process_timeslice(void)
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{
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FAR struct tcb_s *rtcb = (FAR struct tcb_s*)g_readytorun.head;
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/* Check if the currently executing task uses round robin
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* scheduling.
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*/
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if ((rtcb->flags & TCB_FLAG_ROUND_ROBIN) != 0)
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{
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/* Yes, check if decrementing the timeslice counter
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* would cause the timeslice to expire
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*/
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if (rtcb->timeslice <= 1)
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{
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/* Yes, Now check if the task has pre-emption disabled.
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* If so, then we will freeze the timeslice count at
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* the value until the next tick after pre-emption
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* has been enabled.
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*/
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if (!rtcb->lockcount)
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{
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/* Reset the timeslice in any case. */
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rtcb->timeslice = CONFIG_RR_INTERVAL / MSEC_PER_TICK;
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/* We know we are at the head of the ready to run
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* prioritized list. We must be the highest priority
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* task eligible for execution. Check the next task
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* in the ready to run list. If it is the same
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* priority, then we need to relinquish the CPU and
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* give that task a shot.
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*/
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if (rtcb->flink &&
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rtcb->flink->sched_priority >= rtcb->sched_priority)
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{
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/* Just resetting the task priority to its current
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* value. This this will cause the task to be
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* rescheduled behind any other tasks at the same
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* priority.
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*/
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up_reprioritize_rtr(rtcb, rtcb->sched_priority);
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}
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}
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}
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else
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{
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/* Decrement the timeslice counter */
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rtcb->timeslice--;
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}
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}
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}
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#else
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# define sched_process_timeslice()
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#endif
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/************************************************************************
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* Public Functions
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************************************************************************/
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/************************************************************************
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* System Timer Hooks
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*
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* These are standard interfaces that are exported by the OS
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* for use by the architecture specific logic
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*
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************************************************************************/
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/************************************************************************
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* Name: sched_process_timer
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*
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* Description:
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* This function handles system timer events.
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* The timer interrupt logic itself is implemented in the
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* architecture specific code, but must call the following OS
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* function periodically -- the calling interval must be
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* MSEC_PER_TICK
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*
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* Inputs:
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* None
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*
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* Return Value:
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* None
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*
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************************************************************************/
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void sched_process_timer(void)
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{
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/* Increment the system time (if in the link) */
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#ifndef CONFIG_DISABLE_CLOCK
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#ifdef CONFIG_HAVE_WEAKFUNCTIONS
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if (clock_timer != NULL)
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#endif
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{
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clock_timer();
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}
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#endif
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/* Perform CPU load measurements (before any timer-initiated context switches
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* can occur)
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*/
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#ifdef CONFIG_SCHED_CPULOAD
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#ifdef CONFIG_HAVE_WEAKFUNCTIONS
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if (sched_process_cpuload != NULL)
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#endif
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{
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sched_process_cpuload();
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}
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#endif
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/* Process watchdogs (if in the link) */
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#ifdef CONFIG_HAVE_WEAKFUNCTIONS
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if (wd_timer != NULL)
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#endif
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{
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wd_timer();
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}
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/* Check if the currently executing task has exceeded its
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* timeslice.
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*/
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sched_process_timeslice();
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}
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