82 lines
2.9 KiB
C
82 lines
2.9 KiB
C
/****************************************************************************
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* libc/sched/sched_cpucount.c
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*
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* Copyright (C) 2016 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 <sched.h>
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#ifdef CONFIG_SMP
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: sched_cpu_count
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*
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* Description:
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* Return the number of bits set in the 'set'. This could be improved by
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* using CPU-specific bit counting instructions.
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*
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* Inputs:
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* set - The set of CPUs to be counted.
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*
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* Return Value:
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* The number of CPUs in 'set'
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*
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****************************************************************************/
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int sched_cpu_count(FAR const cpu_set_t *set)
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{
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int count;
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int cpu;
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for (cpu = 0, count = 0; cpu < CONFIG_SMP_NCPUS; cpu++)
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{
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if ((*set & (1 << cpu)) != 0)
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{
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count++;
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}
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}
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return count;
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}
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#endif /* CONFIG_SMP */
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