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CPU load: Correct computation of the nominal period to use when the source is a oneshot timer.

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This commit is contained in:
Gregory Nutt 2017-01-22 07:12:22 -06:00
parent 1e38884088
commit 686041f8e7
2 changed files with 26 additions and 8 deletions
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4
sched/Kconfig
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@ -654,8 +654,8 @@ config CPULOAD_ONESHOT_ENTROPY
Where
CPULOAD_ONESHOT_NOMINAL is CONFIG_SCHED_CPULOAD_TICKSPERSEC in
units of microseconds.
CPULOAD_ONESHOT_NOMINAL is the nominal sample internval implied
by CONFIG_SCHED_CPULOAD_TICKSPERSEC in units of microseconds.
CPULOAD_ONESHOT_ENTROPY is (1 << CONFIG_CPULOAD_ONESHOT_ENTROPY),
and
'error' is an error value that is retained from interval to

30
sched/sched/sched_cpuload_oneshot.c
View File

@ -1,7 +1,7 @@
/****************************************************************************
* sched/sched/sched_cpuload_oneshot.c
*
* Copyright (C) 2016 Gregory Nutt. All rights reserved.
* Copyright (C) 2016-2017 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
@ -56,25 +56,43 @@
* Pre-processor Definitions
****************************************************************************/
/* Configuration ************************************************************/
#if !defined(CONFIG_SCHED_CPULOAD) || !defined(CONFIG_SCHED_CPULOAD_EXTCLK)
# error CONFIG_SCHED_CPULOAD and CONFIG_SCHED_CPULOAD_EXTCLK must be defined
#endif
/* CONFIG_SCHED_CPULOAD_TICKSPERSEC is the frequency of the external clock
* source.
*/
#ifndef CONFIG_SCHED_CPULOAD_TICKSPERSEC
# error CONFIG_SCHED_CPULOAD_TICKSPERSEC not defined
#endif
#define CPULOAD_ONESHOT_NOMINAL (CONFIG_SCHED_CPULOAD_TICKSPERSEC * 1000)
#if CPULOAD_ONESHOT_NOMINAL < 1 || CPULOAD_ONESHOT_NOMINAL > 0x7fffffff
# error CPULOAD_ONESHOT_NOMINAL is out of range
#endif
/* CONFIG_CPULOAD_ONESHOT_ENTROPY determines that amount of random "jitter"
* that will be added to the nominal sample interval. Specified as a number
* bits.
*/
#ifndef CONFIG_CPULOAD_ONESHOT_ENTROPY
# warning CONFIG_CPULOAD_ONESHOT_ENTROPY not defined
# define CONFIG_CPULOAD_ONESHOT_ENTROPY 0
#endif
/* Calculate the nomimal sample interval in microseconds:
*
* nominal = (1,000,000 usec/sec) / Frequency cycles/sec) = Period usec/cycle
*/
#define CPULOAD_ONESHOT_NOMINAL (1000000 / CONFIG_SCHED_CPULOAD_TICKSPERSEC)
#if CPULOAD_ONESHOT_NOMINAL < 1 || CPULOAD_ONESHOT_NOMINAL > 0x7fffffff
# error CPULOAD_ONESHOT_NOMINAL is out of range
#endif
/* Convert the entropy from number of bits to a numeric value */
#define CPULOAD_ONESHOT_ENTROPY (1 << CONFIG_CPULOAD_ONESHOT_ENTROPY)
#if CPULOAD_ONESHOT_NOMINAL < CPULOAD_ONESHOT_ENTROPY