mirror of
https://github.com/FreeRTOS/FreeRTOS-Kernel.git
synced 2025-12-15 16:15:08 -05:00
Replace exponential_backoff with submodule to FreeRTOS/backoffAlgorithm (#419)
A new repository, FreeRTOS/backoffAlgorithm, has been created for hosting the library for backoff calculation. This repo replaces the FreeRTOS-Plus/Source/Utilities/exponential_backoff with the submodule to the new repository, and updates all the demos that use retry logic to use the backoffAlgorithm API
This commit is contained in:
Archit Aggarwal
GitHub
parent
5ba1e4cf95
commit
036ec83b65
33 changed files with 699 additions and 554 deletions
1
FreeRTOS-Plus/Source/Utilities/backoff_algorithm
Submodule
1
FreeRTOS-Plus/Source/Utilities/backoff_algorithm
Submodule
|
|
@ -0,0 +1 @@
|
|||
Subproject commit bc5ce2ed93ac063d75a4d3661e5253477c4e4fef
|
||||
|
|
@ -1,101 +0,0 @@
|
|||
/*
|
||||
* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
|
||||
*
|
||||
* Permission is hereby granted, free of charge, to any person obtaining a copy of
|
||||
* this software and associated documentation files (the "Software"), to deal in
|
||||
* the Software without restriction, including without limitation the rights to
|
||||
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
|
||||
* the Software, and to permit persons to whom the Software is furnished to do so,
|
||||
* subject to the following conditions:
|
||||
*
|
||||
* The above copyright notice and this permission notice shall be included in all
|
||||
* copies or substantial portions of the Software.
|
||||
*
|
||||
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
||||
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
|
||||
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
|
||||
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
|
||||
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
|
||||
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
|
||||
*/
|
||||
|
||||
/**
|
||||
* @file exponential_backoff.c
|
||||
* @brief Utility implementation of backoff logic, used for attempting retries of failed processes.
|
||||
*/
|
||||
|
||||
/* Standard includes. */
|
||||
#include <stdint.h>
|
||||
|
||||
/* Kernel includes. */
|
||||
#include "FreeRTOS.h"
|
||||
#include "task.h"
|
||||
|
||||
#include "exponential_backoff.h"
|
||||
|
||||
#define MILLISECONDS_PER_SECOND ( 1000U ) /**< @brief Milliseconds per second. */
|
||||
|
||||
extern UBaseType_t uxRand( void );
|
||||
|
||||
/*-----------------------------------------------------------*/
|
||||
|
||||
RetryUtilsStatus_t RetryUtils_BackoffAndSleep( RetryUtilsParams_t * pRetryParams )
|
||||
{
|
||||
RetryUtilsStatus_t status = RetryUtilsRetriesExhausted;
|
||||
uint32_t backOffDelayMs = 0;
|
||||
|
||||
/* If pRetryParams->maxRetryAttempts is set to 0, try forever. */
|
||||
if( ( pRetryParams->attemptsDone < pRetryParams->maxRetryAttempts ) ||
|
||||
( 0U == pRetryParams->maxRetryAttempts ) )
|
||||
{
|
||||
/* Choose a random value for back-off time between 0 and the max jitter value. */
|
||||
backOffDelayMs = uxRand() % pRetryParams->nextJitterMax;
|
||||
|
||||
/* Wait for backoff time to expire for the next retry. */
|
||||
vTaskDelay( pdMS_TO_TICKS( backOffDelayMs * MILLISECONDS_PER_SECOND ) );
|
||||
|
||||
/* Increment backoff counts. */
|
||||
pRetryParams->attemptsDone++;
|
||||
|
||||
/* Double the max jitter value for the next retry attempt, only
|
||||
* if the new value will be less than the max backoff time value. */
|
||||
if( pRetryParams->nextJitterMax < ( MAX_RETRY_BACKOFF_SECONDS / 2U ) )
|
||||
{
|
||||
pRetryParams->nextJitterMax += pRetryParams->nextJitterMax;
|
||||
}
|
||||
else
|
||||
{
|
||||
pRetryParams->nextJitterMax = MAX_RETRY_BACKOFF_SECONDS;
|
||||
}
|
||||
|
||||
status = RetryUtilsSuccess;
|
||||
}
|
||||
else
|
||||
{
|
||||
/* When max retry attempts are exhausted, let application know by
|
||||
* returning RetryUtilsRetriesExhausted. Application may choose to
|
||||
* restart the retry process after calling RetryUtils_ParamsReset(). */
|
||||
status = RetryUtilsRetriesExhausted;
|
||||
RetryUtils_ParamsReset( pRetryParams );
|
||||
}
|
||||
|
||||
return status;
|
||||
}
|
||||
|
||||
/*-----------------------------------------------------------*/
|
||||
|
||||
void RetryUtils_ParamsReset( RetryUtilsParams_t * pRetryParams )
|
||||
{
|
||||
uint32_t jitter = 0;
|
||||
|
||||
/* Reset attempts done to zero so that the next retry cycle can start. */
|
||||
pRetryParams->attemptsDone = 0;
|
||||
|
||||
/* Calculate jitter value using picking a random number. */
|
||||
jitter = ( uxRand() % MAX_JITTER_VALUE_SECONDS );
|
||||
|
||||
/* Reset the backoff value to the initial time out value plus jitter. */
|
||||
pRetryParams->nextJitterMax = INITIAL_RETRY_BACKOFF_SECONDS + jitter;
|
||||
}
|
||||
|
||||
/*-----------------------------------------------------------*/
|
||||
|
|
@ -1,245 +0,0 @@
|
|||
/*
|
||||
* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
|
||||
*
|
||||
* Permission is hereby granted, free of charge, to any person obtaining a copy of
|
||||
* this software and associated documentation files (the "Software"), to deal in
|
||||
* the Software without restriction, including without limitation the rights to
|
||||
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
|
||||
* the Software, and to permit persons to whom the Software is furnished to do so,
|
||||
* subject to the following conditions:
|
||||
*
|
||||
* The above copyright notice and this permission notice shall be included in all
|
||||
* copies or substantial portions of the Software.
|
||||
*
|
||||
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
||||
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
|
||||
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
|
||||
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
|
||||
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
|
||||
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
|
||||
*/
|
||||
|
||||
/**
|
||||
* @file exponential_backoff.h
|
||||
* @brief Declaration of the exponential backoff retry logic utility functions
|
||||
* and constants.
|
||||
*/
|
||||
|
||||
#ifndef EXPONENTIAL_BACKOFF_H
|
||||
#define EXPONENTIAL_BACKOFF_H
|
||||
|
||||
/* Standard include. */
|
||||
#include <stdint.h>
|
||||
|
||||
/**
|
||||
* @page retryutils_page Retry Utilities
|
||||
* @brief An abstraction of utilities for retrying with exponential back off and
|
||||
* jitter.
|
||||
*
|
||||
* @section retryutils_overview Overview
|
||||
* The retry utilities are a set of APIs that aid in retrying with exponential
|
||||
* backoff and jitter. Exponential backoff with jitter is strongly recommended
|
||||
* for retrying failed actions over the network with servers. Please see
|
||||
* https://aws.amazon.com/blogs/architecture/exponential-backoff-and-jitter/ for
|
||||
* more information about the benefits with AWS.
|
||||
*
|
||||
* Exponential backoff with jitter is typically used when retrying a failed
|
||||
* connection to the server. In an environment with poor connectivity, a client
|
||||
* can get disconnected at any time. A backoff strategy helps the client to
|
||||
* conserve battery by not repeatedly attempting reconnections when they are
|
||||
* unlikely to succeed.
|
||||
*
|
||||
* Before retrying the failed communication to the server there is a quiet period.
|
||||
* In this quiet period, the task that is retrying must sleep for some random
|
||||
* amount of seconds between 0 and the lesser of a base value and a predefined
|
||||
* maximum. The base is doubled with each retry attempt until the maximum is
|
||||
* reached.<br>
|
||||
*
|
||||
* > sleep_seconds = random_between( 0, min( 2<sup>attempts_count</sup> * base_seconds, maximum_seconds ) )
|
||||
*
|
||||
* @section retryutils_implementation Implementing Retry Utils
|
||||
*
|
||||
* The functions that must be implemented are:<br>
|
||||
* - @ref RetryUtils_ParamsReset
|
||||
* - @ref RetryUtils_BackoffAndSleep
|
||||
*
|
||||
* The functions are used as shown in the diagram below. This is the exponential
|
||||
* backoff with jitter loop:
|
||||
*
|
||||
* @image html exponential_backoff_flow.png width=25%
|
||||
*
|
||||
* The following steps give guidance on implementing the Retry Utils. An example
|
||||
* implementation of the Retry Utils for the FreeRTOS platform can be found in file
|
||||
* @ref exponential_backoff.c.
|
||||
*
|
||||
* -# Implementing @ref RetryUtils_ParamsReset
|
||||
* @snippet this define_retryutils_paramsreset
|
||||
*<br>
|
||||
* This function initializes @ref RetryUtilsParams_t. It is expected to set
|
||||
* @ref RetryUtilsParams_t.attemptsDone to zero. It is also expected to set
|
||||
* @ref RetryUtilsParams_t.nextJitterMax to @ref INITIAL_RETRY_BACKOFF_SECONDS
|
||||
* plus some random amount of seconds, jitter. This jitter is a random number
|
||||
* between 0 and @ref MAX_JITTER_VALUE_SECONDS. This function must be called
|
||||
* before entering the exponential backoff with jitter loop using
|
||||
* @ref RetryUtils_BackoffAndSleep.<br><br>
|
||||
* Please follow the example below to implement your own @ref RetryUtils_ParamsReset.
|
||||
* The lines with FIXME comments should be updated.
|
||||
* @code{c}
|
||||
* void RetryUtils_ParamsReset( RetryUtilsParams_t * pRetryParams )
|
||||
* {
|
||||
* uint32_t jitter = 0;
|
||||
*
|
||||
* // Reset attempts done to zero so that the next retry cycle can start.
|
||||
* pRetryParams->attemptsDone = 0;
|
||||
*
|
||||
* // Seed pseudo random number generator with the current time. FIXME: Your
|
||||
* // system may have another method to retrieve the current time to seed the
|
||||
* // pseudo random number generator.
|
||||
* srand( time( NULL ) );
|
||||
*
|
||||
* // Calculate jitter value using picking a random number.
|
||||
* jitter = ( rand() % MAX_JITTER_VALUE_SECONDS );
|
||||
*
|
||||
* // Reset the backoff value to the initial time out value plus jitter.
|
||||
* pRetryParams->nextJitterMax = INITIAL_RETRY_BACKOFF_SECONDS + jitter;
|
||||
* }
|
||||
* @endcode<br>
|
||||
*
|
||||
* -# Implementing @ref RetryUtils_BackoffAndSleep
|
||||
* @snippet this define_retryutils_backoffandsleep
|
||||
* <br>
|
||||
* When this function is invoked, the calling task is expected to sleep a random
|
||||
* number of seconds between 0 and @ref RetryUtilsParams_t.nextJitterMax. After
|
||||
* sleeping this function must double @ref RetryUtilsParams_t.nextJitterMax, but
|
||||
* not exceeding @ref MAX_RETRY_BACKOFF_SECONDS. When @ref RetryUtilsParams_t.maxRetryAttempts
|
||||
* are reached this function should return @ref RetryUtilsRetriesExhausted, unless
|
||||
* @ref RetryUtilsParams_t.maxRetryAttempts is set to zero.
|
||||
* When @ref RetryUtilsRetriesExhausted is returned the calling application can
|
||||
* stop trying with a failure, or it can call @ref RetryUtils_ParamsReset again
|
||||
* and restart the exponential back off with jitter loop.<br><br>
|
||||
* Please follow the example below to implement your own @ref RetryUtils_BackoffAndSleep.
|
||||
* The lines with FIXME comments should be updated.
|
||||
* @code{c}
|
||||
* RetryUtilsStatus_t RetryUtils_BackoffAndSleep( RetryUtilsParams_t * pRetryParams )
|
||||
* {
|
||||
* RetryUtilsStatus_t status = RetryUtilsRetriesExhausted;
|
||||
* // The quiet period delay in seconds.
|
||||
* int backOffDelay = 0;
|
||||
*
|
||||
* // If pRetryParams->maxRetryAttempts is set to 0, try forever.
|
||||
* if( ( pRetryParams->attemptsDone < pRetryParams->maxRetryAttempts ) ||
|
||||
* ( 0U == pRetryParams->maxRetryAttempts ) )
|
||||
* {
|
||||
* // Choose a random value for back-off time between 0 and the max jitter value.
|
||||
* backOffDelay = rand() % pRetryParams->nextJitterMax;
|
||||
*
|
||||
* // Wait for backoff time to expire for the next retry.
|
||||
* ( void ) myThreadSleepFunction( backOffDelay ); // FIXME: Replace with your system's thread sleep function.
|
||||
*
|
||||
* // Increment backoff counts.
|
||||
* pRetryParams->attemptsDone++;
|
||||
*
|
||||
* // Double the max jitter value for the next retry attempt, only
|
||||
* // if the new value will be less than the max backoff time value.
|
||||
* if( pRetryParams->nextJitterMax < ( MAX_RETRY_BACKOFF_SECONDS / 2U ) )
|
||||
* {
|
||||
* pRetryParams->nextJitterMax += pRetryParams->nextJitterMax;
|
||||
* }
|
||||
* else
|
||||
* {
|
||||
* pRetryParams->nextJitterMax = MAX_RETRY_BACKOFF_SECONDS;
|
||||
* }
|
||||
*
|
||||
* status = RetryUtilsSuccess;
|
||||
* }
|
||||
* else
|
||||
* {
|
||||
* // When max retry attempts are exhausted, let application know by
|
||||
* // returning RetryUtilsRetriesExhausted. Application may choose to
|
||||
* // restart the retry process after calling RetryUtils_ParamsReset().
|
||||
* status = RetryUtilsRetriesExhausted;
|
||||
* RetryUtils_ParamsReset( pRetryParams );
|
||||
* }
|
||||
*
|
||||
* return status;
|
||||
* }
|
||||
* @endcode
|
||||
*/
|
||||
|
||||
/**
|
||||
* @brief Max number of retry attempts. Set this value to 0 if the client must
|
||||
* retry forever.
|
||||
*/
|
||||
#define MAX_RETRY_ATTEMPTS 4U
|
||||
|
||||
/**
|
||||
* @brief Initial fixed backoff value in seconds between two successive
|
||||
* retries. A random jitter value is added to every backoff value.
|
||||
*/
|
||||
#define INITIAL_RETRY_BACKOFF_SECONDS 1U
|
||||
|
||||
/**
|
||||
* @brief Max backoff value in seconds.
|
||||
*/
|
||||
#define MAX_RETRY_BACKOFF_SECONDS 128U
|
||||
|
||||
/**
|
||||
* @brief Max jitter value in seconds.
|
||||
*/
|
||||
#define MAX_JITTER_VALUE_SECONDS 5U
|
||||
|
||||
/**
|
||||
* @brief Status for @ref RetryUtils_BackoffAndSleep.
|
||||
*/
|
||||
typedef enum RetryUtilsStatus
|
||||
{
|
||||
RetryUtilsSuccess = 0, /**< @brief The function returned successfully after sleeping. */
|
||||
RetryUtilsRetriesExhausted /**< @brief The function exhausted all retry attempts. */
|
||||
} RetryUtilsStatus_t;
|
||||
|
||||
/**
|
||||
* @brief Represents parameters required for retry logic.
|
||||
*/
|
||||
typedef struct RetryUtilsParams
|
||||
{
|
||||
/**
|
||||
* @brief Max number of retry attempts. Set this value to 0 if the client must
|
||||
* retry forever.
|
||||
*/
|
||||
uint32_t maxRetryAttempts;
|
||||
|
||||
/**
|
||||
* @brief The cumulative count of backoff delay cycles completed
|
||||
* for retries.
|
||||
*/
|
||||
uint32_t attemptsDone;
|
||||
|
||||
/**
|
||||
* @brief The max jitter value for backoff time in retry attempt.
|
||||
*/
|
||||
uint32_t nextJitterMax;
|
||||
} RetryUtilsParams_t;
|
||||
|
||||
|
||||
/**
|
||||
* @brief Resets the retry timeout value and number of attempts.
|
||||
* This function must be called by the application before a new retry attempt.
|
||||
*
|
||||
* @param[in, out] pRetryParams Structure containing attempts done and timeout
|
||||
* value.
|
||||
*/
|
||||
void RetryUtils_ParamsReset( RetryUtilsParams_t * pRetryParams );
|
||||
|
||||
/**
|
||||
* @brief Simple platform specific exponential backoff function. The application
|
||||
* must use this function between retry failures to add exponential delay.
|
||||
* This function will block the calling task for the current timeout value.
|
||||
*
|
||||
* @param[in, out] pRetryParams Structure containing retry parameters.
|
||||
*
|
||||
* @return #RetryUtilsSuccess after a successful sleep, #RetryUtilsRetriesExhausted
|
||||
* when all attempts are exhausted.
|
||||
*/
|
||||
RetryUtilsStatus_t RetryUtils_BackoffAndSleep( RetryUtilsParams_t * pRetryParams );
|
||||
|
||||
#endif /* ifndef EXPONENTIAL_BACKOFF_H */
|
||||
|
|
@ -1,6 +1,6 @@
|
|||
Directories:
|
||||
|
||||
+ Utilities/exponential_backoff contains a utility that calculates an
|
||||
+ Utilities/backoff_algorithm contains a utility that calculates an
|
||||
exponential back off time, with some jitter. It is used to ensure fleets of
|
||||
IoT devices that become disconnected don't all try and reconnect at the same
|
||||
time.
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue