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/* Copyright (c) 2015-2018, Linaro Limited
* All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
/**
* @file
*
* ODP CPU API
*/
#ifndef ODP_API_SPEC_CPU_H_
#define ODP_API_SPEC_CPU_H_
#include <odp/visibility_begin.h>
#ifdef __cplusplus
extern "C" {
#endif
#include <odp/api/std_types.h>
/** @defgroup odp_cpu ODP CPU
* CPU cycle count, frequency, etc. information.
* @{
*/
/**
* CPU identifier
*
* Determine CPU identifier on which the calling is running. CPU numbering is
* system specific.
*
* @return CPU identifier
*/
int odp_cpu_id(void);
/**
* CPU count
*
* Report the number of CPU's available to this ODP program.
* This may be smaller than the number of (online) CPU's in the system.
*
* @return Number of available CPU's
*/
int odp_cpu_count(void);
/**
* CPU model name of this CPU
*
* Returns the CPU model name of this CPU.
*
* @return Pointer to CPU model name string
*/
const char *odp_cpu_model_str(void);
/**
* CPU model name of a CPU
*
* Return CPU model name of the specified CPU.
*
* @param id CPU ID
*
* @return Pointer to CPU model name string
*/
const char *odp_cpu_model_str_id(int id);
/**
* Current CPU frequency in Hz
*
* Returns current frequency of this CPU. Returns zero if the frequency
* request is not supported.
*
* @return CPU frequency in Hz
* @retval 0 Not supported or a failure
*/
uint64_t odp_cpu_hz(void);
/**
* Current CPU frequency of a CPU (in Hz)
*
* Returns current frequency of the specified CPU. Returns zero if the frequency
* request is not supported.
*
* @param id CPU ID
*
* @return CPU frequency in Hz
* @retval 0 Not supported or a failure
*/
uint64_t odp_cpu_hz_id(int id);
/**
* Maximum CPU frequency in Hz
*
* Returns the maximum frequency of this CPU. Returns zero if the frequency
* request is not supported.
*
* @return CPU frequency in Hz
* @retval 0 Not supported or a failure
*/
uint64_t odp_cpu_hz_max(void);
/**
* Maximum CPU frequency of a CPU (in Hz)
*
* Returns the maximum frequency of the specified CPU. Returns zero if the
* frequency request is not supported.
*
* @param id CPU ID
*
* @return CPU frequency in Hz
* @retval 0 Not supported or a failure
*/
uint64_t odp_cpu_hz_max_id(int id);
/**
* Current CPU cycle count
*
* Return current CPU cycle count. Cycle count may not be reset at ODP init
* and thus may wrap back to zero between two calls. Use odp_cpu_cycles_max()
* to read the maximum count value after which it wraps. Cycle count frequency
* follows the CPU frequency and thus may change at any time. Cycle count should
* not be used for time measurements due to the possibility of frequency
* variation. The count may advance in steps larger than one. Use
* odp_cpu_cycles_resolution() to read the step size.
*
* Returns zero if CPU cycle counter is not supported.
*
* @return Current CPU cycle count
* @retval 0 Not supported
*/
uint64_t odp_cpu_cycles(void);
/**
* CPU cycle count difference
*
* Calculate difference between cycle counts c1 and c2. Parameter c1 must be the
* first cycle count sample and c2 the second. The function handles correctly
* single cycle count wrap between c1 and c2.
*
* @param c2 Second cycle count
* @param c1 First cycle count
*
* @return CPU cycles from c1 to c2
*/
uint64_t odp_cpu_cycles_diff(uint64_t c2, uint64_t c1);
/**
* Maximum CPU cycle count
*
* Maximum CPU cycle count value before it wraps back to zero. Returns zero
* if CPU cycle counter is not supported.
*
* @return Maximum CPU cycle count value
* @retval 0 Not supported
*/
uint64_t odp_cpu_cycles_max(void);
/**
* Resolution of CPU cycle count
*
* CPU cycle count may advance in steps larger than one. This function returns
* resolution of odp_cpu_cycles() in CPU cycles. Returns zero if CPU cycle
* counter is not supported.
*
* @return CPU cycle count resolution in CPU cycles
* @retval 0 Not supported
*/
uint64_t odp_cpu_cycles_resolution(void);
/**
* Pause CPU execution for a short while
*
* This call is intended for tight loops which poll a shared resource. A short
* pause within the loop may save energy and improve system performance as
* CPU polling frequency is reduced.
*/
void odp_cpu_pause(void);
/**
* @}
*/
#ifdef __cplusplus
}
#endif
#include <odp/visibility_end.h>
#endif
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