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Diffstat (limited to 'include/iprt/timer.h')
| -rw-r--r-- | include/iprt/timer.h | 379 |
1 files changed, 379 insertions, 0 deletions
diff --git a/include/iprt/timer.h b/include/iprt/timer.h new file mode 100644 index 00000000..54e63a7a --- /dev/null +++ b/include/iprt/timer.h @@ -0,0 +1,379 @@ +/** @file + * IPRT - Timer. + */ + +/* + * Copyright (C) 2006-2012 Oracle Corporation + * + * This file is part of VirtualBox Open Source Edition (OSE), as + * available from http://www.virtualbox.org. This file is free software; + * you can redistribute it and/or modify it under the terms of the GNU + * General Public License (GPL) as published by the Free Software + * Foundation, in version 2 as it comes in the "COPYING" file of the + * VirtualBox OSE distribution. VirtualBox OSE is distributed in the + * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind. + * + * The contents of this file may alternatively be used under the terms + * of the Common Development and Distribution License Version 1.0 + * (CDDL) only, as it comes in the "COPYING.CDDL" file of the + * VirtualBox OSE distribution, in which case the provisions of the + * CDDL are applicable instead of those of the GPL. + * + * You may elect to license modified versions of this file under the + * terms and conditions of either the GPL or the CDDL or both. + */ + +#ifndef ___iprt_timer_h +#define ___iprt_timer_h + + +#include <iprt/cdefs.h> +#include <iprt/types.h> + + +RT_C_DECLS_BEGIN + +/** @defgroup grp_rt_timer RTTimer - Timer + * + * The IPRT timer API provides a simple abstraction of recurring and one-shot callback timers. + * + * Because of the great variation in the native APIs and the quality of + * the service delivered by those native APIs, the timers are operated + * on at best effort basis. + * + * All the ring-3 implementations are naturally at the mercy of the scheduler, + * which means that the callback rate might vary quite a bit and we might skip + * ticks. Many systems have a restriction that a process can only have one + * timer. IPRT currently makes no efforts at multiplexing timers in those kind + * of situations and will simply fail if you try to create more than one timer. + * + * Things are generally better in ring-0. The implementations will use interrupt + * time callbacks wherever available, and if not, resort to a high priority + * kernel thread. + * + * @ingroup grp_rt + * @{ + */ + + +/** Timer handle. */ +typedef struct RTTIMER *PRTTIMER; + +/** + * Timer callback function. + * + * The context this call is made in varies with different platforms and + * kernel / user mode IPRT. + * + * In kernel mode a timer callback should not waste time, it shouldn't + * waste stack and it should be prepared that some APIs might not work + * correctly because of weird OS restrictions in this context that we + * haven't discovered and avoided yet. Please fix those APIs so they + * at least avoid panics and weird behaviour. + * + * @param pTimer Timer handle. + * @param pvUser User argument. + * @param iTick The current timer tick. This is always 1 on the first + * callback after the timer was started. For omni timers + * this will be 1 when a cpu comes back online. + */ +typedef DECLCALLBACK(void) FNRTTIMER(PRTTIMER pTimer, void *pvUser, uint64_t iTick); +/** Pointer to FNRTTIMER() function. */ +typedef FNRTTIMER *PFNRTTIMER; + + +/** + * Create a recurring timer. + * + * @returns iprt status code. + * @param ppTimer Where to store the timer handle. + * @param uMilliesInterval Milliseconds between the timer ticks. + * This is rounded up to the system granularity. + * @param pfnTimer Callback function which shall be scheduled for execution + * on every timer tick. + * @param pvUser User argument for the callback. + * @see RTTimerCreateEx, RTTimerStart, RTTimerStop, RTTimerChangeInterval, + * RTTimerDestroy, RTTimerGetSystemGranularity + */ +RTDECL(int) RTTimerCreate(PRTTIMER *ppTimer, unsigned uMilliesInterval, PFNRTTIMER pfnTimer, void *pvUser); + +/** + * Create a suspended timer. + * + * @returns iprt status code. + * @retval VERR_NOT_SUPPORTED if an unsupported flag was specfied. + * @retval VERR_CPU_NOT_FOUND if the specified CPU + * + * @param ppTimer Where to store the timer handle. + * @param u64NanoInterval The interval between timer ticks specified in nanoseconds if it's + * a recurring timer. This is rounded to the fit the system timer granularity. + * For one shot timers, pass 0. + * @param fFlags Timer flags. + * @param pfnTimer Callback function which shall be scheduled for execution + * on every timer tick. + * @param pvUser User argument for the callback. + * @see RTTimerStart, RTTimerStop, RTTimerChangeInterval, RTTimerDestroy, + * RTTimerGetSystemGranularity, RTTimerCanDoHighResolution + */ +RTDECL(int) RTTimerCreateEx(PRTTIMER *ppTimer, uint64_t u64NanoInterval, uint32_t fFlags, PFNRTTIMER pfnTimer, void *pvUser); + +/** @name RTTimerCreateEx flags + * @{ */ +/** Any CPU is fine. (Must be 0.) */ +#define RTTIMER_FLAGS_CPU_ANY UINT32_C(0) +/** One specific CPU */ +#define RTTIMER_FLAGS_CPU_SPECIFIC RT_BIT(8) +/** Omni timer, run on all online CPUs. + * @remarks The timer callback isn't necessarily running at the time same time on each CPU. */ +#define RTTIMER_FLAGS_CPU_ALL ( RTTIMER_FLAGS_CPU_MASK | RTTIMER_FLAGS_CPU_SPECIFIC ) +/** CPU mask. */ +#define RTTIMER_FLAGS_CPU_MASK UINT32_C(0xff) +/** Desire a high resolution timer that works with RTTimerChangeInterval and + * isn't subject to RTTimerGetSystemGranularity rounding. + * @remarks This is quietly ignored if the feature isn't supported. */ +#define RTTIMER_FLAGS_HIGH_RES RT_BIT(9) +/** Convert a CPU set index (0-based) to RTTimerCreateEx flags. + * This will automatically OR in the RTTIMER_FLAGS_CPU_SPECIFIC flag. */ +#define RTTIMER_FLAGS_CPU(iCpu) ( (iCpu) | RTTIMER_FLAGS_CPU_SPECIFIC ) +/** Macro that validates the flags. */ +#define RTTIMER_FLAGS_ARE_VALID(fFlags) \ + ( !((fFlags) & ~((fFlags) & RTTIMER_FLAGS_CPU_SPECIFIC ? UINT32_C(0x3ff) : UINT32_C(0x300))) ) +/** @} */ + +/** + * Stops and destroys a running timer. + * + * @returns iprt status code. + * @param pTimer Timer to stop and destroy. NULL is ok. + */ +RTDECL(int) RTTimerDestroy(PRTTIMER pTimer); + +/** + * Starts a suspended timer. + * + * @returns IPRT status code. + * @retval VERR_INVALID_HANDLE if pTimer isn't valid. + * @retval VERR_TIMER_ACTIVE if the timer isn't suspended. + * @retval VERR_CPU_OFFLINE if the CPU the timer was created to run on is not + * online (this include the case where it's not present in the + * system). + * + * @param pTimer The timer to activate. + * @param u64First The RTTimeSystemNanoTS() for when the timer should start + * firing (relative). If 0 is specified, the timer will + * fire ASAP. + * @remarks When RTTimerCanDoHighResolution returns true, this API is + * callable with preemption disabled in ring-0. + * @see RTTimerStop + */ +RTDECL(int) RTTimerStart(PRTTIMER pTimer, uint64_t u64First); + +/** + * Stops an active timer. + * + * @returns IPRT status code. + * @retval VERR_INVALID_HANDLE if pTimer isn't valid. + * @retval VERR_TIMER_SUSPENDED if the timer isn't active. + * @retval VERR_NOT_SUPPORTED if the IPRT implementation doesn't support + * stopping a timer. + * + * @param pTimer The timer to suspend. + * @remarks Can be called from the timer callback function to stop it. + * @see RTTimerStart + */ +RTDECL(int) RTTimerStop(PRTTIMER pTimer); + +/** + * Changes the interval of a periodic timer. + * + * If the timer is active, it is implementation dependent whether the change + * takes place immediately or after the next tick. To get defined behavior, + * stop the timer before calling this API. + * + * @returns IPRT status code. + * @retval VERR_INVALID_HANDLE if pTimer isn't valid. + * @retval VERR_NOT_SUPPORTED if not supported. + * + * @param pTimer The timer to activate. + * @param u64NanoInterval The interval between timer ticks specified in + * nanoseconds. This is rounded to the fit the + * system timer granularity. + * @remarks Callable from the timer callback. Callable with preemption + * disabled in ring-0. + */ +RTDECL(int) RTTimerChangeInterval(PRTTIMER pTimer, uint64_t u64NanoInterval); + +/** + * Gets the (current) timer granularity of the system. + * + * @returns The timer granularity of the system in nanoseconds. + * @see RTTimerRequestSystemGranularity + */ +RTDECL(uint32_t) RTTimerGetSystemGranularity(void); + +/** + * Requests a specific system timer granularity. + * + * Successfull calls to this API must be coupled with the exact same number of + * calls to RTTimerReleaseSystemGranularity() in order to undo any changes made. + * + * + * @returns IPRT status code. + * @retval VERR_NOT_SUPPORTED if the requested value isn't supported by the host platform + * or if the host platform doesn't support modifying the system timer granularity. + * @retval VERR_PERMISSION_DENIED if the caller doesn't have the necessary privilege to + * modify the system timer granularity. + * + * @param u32Request The requested system timer granularity in nanoseconds. + * @param pu32Granted Where to store the granted system granularity. This is the value + * that should be passed to RTTimerReleaseSystemGranularity(). It + * is what RTTimerGetSystemGranularity() would return immediately + * after the change was made. + * + * The value differ from the request in two ways; rounding and + * scale. Meaning if your request is for 10.000.000 you might + * be granted 10.000.055 or 1.000.000. + * @see RTTimerReleaseSystemGranularity, RTTimerGetSystemGranularity + */ +RTDECL(int) RTTimerRequestSystemGranularity(uint32_t u32Request, uint32_t *pu32Granted); + +/** + * Releases a system timer granularity grant acquired by RTTimerRequestSystemGranularity(). + * + * @returns IPRT status code. + * @retval VERR_NOT_SUPPORTED if the host platform doesn't have any way of modifying + * the system timer granularity. + * @retval VERR_WRONG_ORDER if nobody call RTTimerRequestSystemGranularity() with the + * given grant value. + * @param u32Granted The granted system granularity. + * @see RTTimerRequestSystemGranularity + */ +RTDECL(int) RTTimerReleaseSystemGranularity(uint32_t u32Granted); + +/** + * Checks if the system support high resolution timers. + * + * The kind of support we are checking for is the kind of dynamically + * reprogrammable timers employed by recent Solaris and Linux kernels. It also + * implies that we can specify microsecond (or even better maybe) intervals + * without getting into trouble. + * + * @returns true if supported, false it not. + * + * @remarks Returning true also means RTTimerChangeInterval must be implemented + * and RTTimerStart be callable with preemption disabled. + */ +RTDECL(bool) RTTimerCanDoHighResolution(void); + + +/** + * Timer callback function for low res timers. + * + * This is identical to FNRTTIMER except for the first parameter, so + * see FNRTTIMER for details. + * + * @param hTimerLR The low resolution timer handle. + * @param pvUser User argument. + * @param iTick The current timer tick. This is always 1 on the first + * callback after the timer was started. Will jump if we've + * skipped ticks when lagging behind. + */ +typedef DECLCALLBACK(void) FNRTTIMERLR(RTTIMERLR hTimerLR, void *pvUser, uint64_t iTick); +/** Pointer to FNRTTIMER() function. */ +typedef FNRTTIMERLR *PFNRTTIMERLR; + + +/** + * Create a recurring low resolution timer. + * + * @returns iprt status code. + * @param phTimerLR Where to store the timer handle. + * @param uMilliesInterval Milliseconds between the timer ticks, at least 100 ms. + * If higher resolution is required use the other API. + * @param pfnTimer Callback function which shall be scheduled for execution + * on every timer tick. + * @param pvUser User argument for the callback. + * @see RTTimerLRCreateEx, RTTimerLRDestroy, RTTimerLRStop + */ +RTDECL(int) RTTimerLRCreate(PRTTIMERLR phTimerLR, uint32_t uMilliesInterval, PFNRTTIMERLR pfnTimer, void *pvUser); + +/** + * Create a suspended low resolution timer. + * + * @returns iprt status code. + * @retval VERR_NOT_SUPPORTED if an unsupported flag was specfied. + * + * @param phTimerLR Where to store the timer handle. + * @param u64NanoInterval The interval between timer ticks specified in nanoseconds if it's + * a recurring timer, the minimum for is 100000000 ns. + * For one shot timers, pass 0. + * @param fFlags Timer flags. Same as RTTimerCreateEx. + * @param pfnTimer Callback function which shall be scheduled for execution + * on every timer tick. + * @param pvUser User argument for the callback. + * @see RTTimerLRStart, RTTimerLRStop, RTTimerLRDestroy + */ +RTDECL(int) RTTimerLRCreateEx(PRTTIMERLR phTimerLR, uint64_t u64NanoInterval, uint32_t fFlags, PFNRTTIMERLR pfnTimer, void *pvUser); + +/** + * Stops and destroys a running low resolution timer. + * + * @returns iprt status code. + * @param hTimerLR The low resolution timer to stop and destroy. + * NIL_RTTIMERLR is accepted. + */ +RTDECL(int) RTTimerLRDestroy(RTTIMERLR hTimerLR); + +/** + * Starts a low resolution timer. + * + * @returns IPRT status code. + * @retval VERR_INVALID_HANDLE if pTimer isn't valid. + * @retval VERR_TIMER_ACTIVE if the timer isn't suspended. + * + * @param hTimerLR The low resolution timer to activate. + * @param u64First The RTTimeSystemNanoTS() for when the timer should start + * firing (relative), the minimum is 100000000 ns. + * If 0 is specified, the timer will fire ASAP. + * + * @see RTTimerLRStop + */ +RTDECL(int) RTTimerLRStart(RTTIMERLR hTimerLR, uint64_t u64First); + +/** + * Stops an active low resolution timer. + * + * @returns IPRT status code. + * @retval VERR_INVALID_HANDLE if pTimer isn't valid. + * @retval VERR_TIMER_SUSPENDED if the timer isn't active. + * @retval VERR_NOT_SUPPORTED if the IPRT implementation doesn't support stopping a timer. + * + * @param hTimerLR The low resolution timer to suspend. + * + * @see RTTimerLRStart + */ +RTDECL(int) RTTimerLRStop(RTTIMERLR hTimerLR); + +/** + * Changes the interval of a low resolution timer. + * + * If the timer is active, the next tick will occure immediately just like with + * RTTimerLRStart() when u64First parameter is zero. + * + * @returns IPRT status code. + * @retval VERR_INVALID_HANDLE if pTimer isn't valid. + * @retval VERR_NOT_SUPPORTED if not supported. + * + * @param hTimerLR The low resolution timer to update. + * @param u64NanoInterval The interval between timer ticks specified in + * nanoseconds. This is rounded to the fit the + * system timer granularity. + * @remarks Callable from the timer callback. + */ +RTDECL(int) RTTimerLRChangeInterval(RTTIMERLR hTimerLR, uint64_t u64NanoInterval); + +/** @} */ + +RT_C_DECLS_END + +#endif |