89ffd44dfb
Adds event based scheduling logic to the kernel. Updates management of timeouts, timers, idling etc. based on time tracked at events rather than periodic ticks. Provides interfaces for timers to announce and get next timer expiry based on kernel scheduling decisions involving time slicing of threads, timeouts and idling. Uses wall time units instead of ticks in all scheduling activities. The implementation involves changes in the following areas 1. Management of time in wall units like ms/us instead of ticks The existing implementation already had an option to configure number of ticks in a second. The new implementation builds on top of that feature and provides option to set the size of the scheduling granurality to mili seconds or micro seconds. This allows most of the current implementation to be reused. Due to this re-use and co-existence with tick based kernel, the names of variables may contain the word "tick". However, in the tickless kernel implementation, it represents the currently configured time unit, which would be be mili seconds or micro seconds. The APIs that take time as a parameter are not impacted and they continue to pass time in mili seconds. 2. Timers would not be programmed in periodic mode generating ticks. Instead they would be programmed in one shot mode to generate events at the time the kernel scheduler needs to gain control for its scheduling activities like timers, timeouts, time slicing, idling etc. 3. The scheduler provides interfaces that the timer drivers use to announce elapsed time and get the next time the scheduler needs a timer event. It is possible that the scheduler may not need another timer event, in which case the system would wait for a non-timer event to wake it up if it is idling. 4. New APIs are defined to be implemented by timer drivers. Also they need to handler timer events differently. These changes have been done in the HPET timer driver. In future other timers that support tickles kernel should implement these APIs as well. These APIs are to re-program the timer, update and announce elapsed time. 5. Philosopher and timer_api applications have been enabled to test tickless kernel. Separate configuration files are created which define the necessary CONFIG flags. Run these apps using following command make pristine && make BOARD=qemu_x86 CONF_FILE=prj_tickless.conf qemu Jira: ZEP-339 ZEP-1946 ZEP-948 Change-Id: I7d950c31bf1ff929a9066fad42c2f0559a2e5983 Signed-off-by: Ramesh Thomas <ramesh.thomas@intel.com>
90 lines
1.9 KiB
C
90 lines
1.9 KiB
C
/*
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* Copyright (c) 2010-2012, 2014-2015 Wind River Systems, Inc.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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/**
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* @file
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* @brief Architecture-independent private kernel APIs
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*
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* This file contains private kernel APIs that are not architecture-specific.
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*/
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#ifndef _NANO_INTERNAL__H_
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#define _NANO_INTERNAL__H_
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#include <kernel.h>
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#define K_NUM_PRIORITIES \
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(CONFIG_NUM_COOP_PRIORITIES + CONFIG_NUM_PREEMPT_PRIORITIES + 1)
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#define K_NUM_PRIO_BITMAPS ((K_NUM_PRIORITIES + 31) >> 5)
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#ifndef _ASMLANGUAGE
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Early boot functions */
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void _bss_zero(void);
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#ifdef CONFIG_XIP
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void _data_copy(void);
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#else
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static inline void _data_copy(void)
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{
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/* Do nothing */
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}
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#endif
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FUNC_NORETURN void _Cstart(void);
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extern void _thread_entry(void (*)(void *, void *, void *),
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void *, void *, void *);
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extern void _new_thread(char *pStack, size_t stackSize,
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void (*pEntry)(void *, void *, void *),
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void *p1, void *p2, void *p3,
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int prio, unsigned int options);
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/* context switching and scheduling-related routines */
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extern unsigned int __swap(unsigned int key);
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#if defined(CONFIG_TICKLESS_KERNEL) && defined(CONFIG_TIMESLICING)
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extern void _update_time_slice_before_swap(void);
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static inline unsigned int _time_slice_swap(unsigned int key)
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{
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_update_time_slice_before_swap();
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return __swap(key);
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}
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#define _Swap(x) _time_slice_swap(x)
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#else
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#define _Swap(x) __swap(x)
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#endif
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/* set and clear essential fiber/task flag */
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extern void _thread_essential_set(void);
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extern void _thread_essential_clear(void);
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/* clean up when a thread is aborted */
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#if defined(CONFIG_THREAD_MONITOR)
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extern void _thread_monitor_exit(struct k_thread *thread);
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#else
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#define _thread_monitor_exit(thread) \
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do {/* nothing */ \
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} while (0)
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#endif /* CONFIG_THREAD_MONITOR */
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#ifdef __cplusplus
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}
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#endif
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#endif /* _ASMLANGUAGE */
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#endif /* _NANO_INTERNAL__H_ */
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