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d8b4d53444
Fix the issue where clock_gettime(CLOCK_MONOTONIC) always returns 0 in
tickless mode, caused by the scheduler tick counter (g_system_ticks) not
being updated with the actual timer ticks.
1. Add clock_update_sched_ticks() function to sched/clock/clock_sched_ticks.c:
a. This function directly sets the system tick counter to a specific value
(vs incrementing in clock_increase_sched_ticks), with full documentation
matching the existing code style.
b. Uses seqlock to ensure thread-safe access to g_system_ticks.
2. Call clock_update_sched_ticks() in nxsched_process_timer() (sched_processtickless.c):
a. Syncs the scheduler tick counter with the actual timer ticks retrieved via up_timer_gettick().
With this fix, g_system_ticks is properly updated in tickless mode,
and clock_gettime(CLOCK_MONOTONIC) returns the correct non-zero monotonic time.
Signed-off-by: chao an <anchao.archer@bytedance.com>
130 lines
4.1 KiB
C
130 lines
4.1 KiB
C
/****************************************************************************
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* sched/clock/clock_sched_ticks.c
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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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 <stdint.h>
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#include <nuttx/irq.h>
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#include <nuttx/arch.h>
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#include <nuttx/clock.h>
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#include <nuttx/seqlock.h>
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#include "clock/clock.h"
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/****************************************************************************
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* Private Data
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****************************************************************************/
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static volatile clock_t g_system_ticks = INITIAL_SYSTEM_TIMER_TICKS;
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static seqcount_t g_system_tick_lock = SEQLOCK_INITIALIZER;
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: clock_update_sched_ticks
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*
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* Description:
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* Update the scheduler tick counter to a specific value. This function
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* directly sets the system tick counter to the given value (rather than
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* incrementing it), typically used for synchronizing or resetting the
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* scheduler tick count to a known state.
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*
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* Input Parameters:
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* ticks - The new value to set for the scheduler tick counter
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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void clock_update_sched_ticks(clock_t ticks)
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{
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irqstate_t flags;
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/* Increment the per-tick scheduler counter */
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flags = write_seqlock_irqsave(&g_system_tick_lock);
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g_system_ticks = ticks;
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write_sequnlock_irqrestore(&g_system_tick_lock, flags);
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}
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/****************************************************************************
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* Name: clock_increase_sched_ticks
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*
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* Description:
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* Increment the scheduler tick counter. This function should be called
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* each time the real-time clock interrupt occurs, indicating the passage
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* of one or more scheduling ticks.
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*
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* Input Parameters:
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* ticks - The number of ticks to increment (typically 1)
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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void clock_increase_sched_ticks(clock_t ticks)
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{
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irqstate_t flags;
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/* Increment the per-tick scheduler counter */
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flags = write_seqlock_irqsave(&g_system_tick_lock);
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g_system_ticks += ticks;
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write_sequnlock_irqrestore(&g_system_tick_lock, flags);
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}
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/****************************************************************************
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* Name: clock_get_sched_ticks
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*
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* Description:
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* Return the current value of the scheduler tick counter. This counter
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* only increases while the scheduler is running, and is independent of
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* the real-time clock.
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*
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* Returned Value:
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* The current number of scheduler ticks.
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*
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****************************************************************************/
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clock_t clock_get_sched_ticks(void)
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{
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clock_t ret;
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unsigned int seq;
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do
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{
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seq = read_seqbegin(&g_system_tick_lock);
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ret = g_system_ticks;
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}
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while (read_seqretry(&g_system_tick_lock, seq));
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return ret;
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}
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