/*
** vim:ts=4 sw=4 expandtab
*/
/*
** Copyright (C) 2009-2011 The University of Melbourne.
**
** This file may only be copied under the terms of the GNU Library General
** Public License - see the file COPYING.LIB in the Mercury distribution.
*/

/*
** mercury_threadscope.h - defines Mercury threadscope profiling support.
**
** See "Parallel Preformance Tuning for Haskell" - Don Jones Jr, Simon Marlow
** and Satnam Singh for information about threadscope.
*/

#ifndef MERCURY_THREADSCOPE_H
#define MERCURY_THREADSCOPE_H

#include "mercury_types.h"      /* for MR_Word, MR_Code, etc */
#include "mercury_engine.h"
#include "mercury_context.h"

#ifdef MR_THREADSCOPE

/*
** Reasons why a context has been stopped, not all of these apply to Mercury,
** for instance contexts don't yield.
*/
#define MR_TS_STOP_REASON_HEAP_OVERFLOW     1
#define MR_TS_STOP_REASON_STACK_OVERFLOW    2
#define MR_TS_STOP_REASON_YIELDING          3
#define MR_TS_STOP_REASON_BLOCKED           4
#define MR_TS_STOP_REASON_FINISHED          5

typedef struct MR_threadscope_event_buffer MR_threadscope_event_buffer_t;

typedef MR_uint_least16_t   MR_ContextStopReason;
typedef MR_Integer          MR_ContextId;
typedef MR_uint_least32_t   MR_TS_StringId;
typedef MR_uint_least32_t   MR_SparkId;
typedef MR_uint_least32_t   MR_EngSetId;
typedef MR_uint_least16_t   MR_EngSetType;
typedef MR_uint_least32_t   MR_TS_Pid;

typedef struct MR_Threadscope_String {
    const char*     MR_tsstring_string;
    MR_TS_StringId  MR_tsstring_id;
} MR_Threadscope_String;

/*
** Set this to true to use the CPU's time stamp counter.
**
** This is initially set in mercury_wrapper.c and may be reset by
** MR_setup_threadscope if the TSC can't be used.
*/
extern MR_bool MR_threadscope_use_tsc;

/*
** This must be called by the primordial thread before starting any other
** threads but after the primordial thread has been pinned.
*/
extern void MR_setup_threadscope(void);

extern void MR_finalize_threadscope(void);

extern void MR_threadscope_setup_engine(MercuryEngine *eng);

extern void MR_threadscope_finalize_engine(MercuryEngine *eng);

#if 0
/*
** It looks like we don't need TSC synchronization code on modern x86(-64) CPUs
** including multi-socket systems (tested on goliath and taura).  If we find
** systems where this is needed we can enable it via a runtime check.
*/
/*
** Synchronize a slave thread's TSC offset to the master's.  The master thread
** (with an engine) should call MR_threadscope_sync_tsc_master() for each slave
** while each slave (with an engine) calls MR_threadscope_sync_tsc_slave().
** All master - slave pairs must be pinned to CPUs and setup their threadscope
** structures already (by calling MR_threadscope_setup_engine() above).
** Multiple slaves may call the _slave at the same time, a lock is used to
** synchronize only one at a time.  Only the primordial thread may call
** MR_threadscope_sync_tsc_master().
*/
extern void MR_threadscope_sync_tsc_master(void);
extern void MR_threadscope_sync_tsc_slave(void);
#endif

/*
** Use the following functions to post messages.  All messages will read the
** current engine's ID from the engine word, some messages will also read the
** current context id from the context loaded into the current engine.
*/

/*
** This context has been created,  The context must be passed as a parameter so
** that it doesn't have to be the current context.
**
** Using the MR_Context typedef here requires the inclusion of
** mercury_context.h, creating a circular dependency
*/
extern void MR_threadscope_post_create_context(
                struct MR_Context_Struct *context);

/*
** The given context was created in order to execute a spark.  This
** event should be posted in addition to (and after) create_thread
** above.
*/
extern void MR_threadscope_post_create_context_for_spark(
                struct MR_Context_Struct *ctxt);

/*
** This context is being released (back into a pool of free contexts).  We may
** see a new create_context or create_context_for_spark message with the same
** context ID, such a message indicates that the context is being re-used.
*/
extern void MR_threadscope_post_release_context(
                struct MR_Context_Struct *context);

/*
** This context is being reused (after being released). This event is an
** alternative to create_context above.
*/
extern void MR_threadscope_post_reuse_context(
                struct MR_Context_Struct *context, MR_Unsigned old_id);

/*
** This message says the context is now ready to run.  Such as it's being
** placed on the run queue after being blocked
*/
extern void MR_threadscope_post_context_runnable(
                struct MR_Context_Struct *context);

/*
** This message says we're now running the current context
*/
extern void MR_threadscope_post_run_context(void);

/*
** This message says we've stopped executing the current context,
** a reason why should be provided.
*/
extern void MR_threadscope_post_stop_context(MR_ContextStopReason reason);

/*
** This message says we're about to execute a spark from our local stack.
*/
extern void MR_threadscope_post_run_spark(MR_SparkId spark_id);

/*
** This message says that we're about to execute a spark that was stolen from
** another's stack.
*/
extern void MR_threadscope_post_steal_spark(MR_SparkId spark_id);

/*
** This message says that a spark is being created for the given computation.
** The spark's ID is given as an argument.
*/
extern void MR_threadscope_post_sparking(MR_Word* dynamic_conj_id,
                MR_SparkId spark_id);

/*
** Post this message just before invoking the main/2 predicate.
*/
extern void MR_threadscope_post_calling_main(void);

/*
** Post this message when an engine begins looking for a context to run.
*/
extern void MR_threadscope_post_looking_for_global_context(void);

/*
** Post this message when an engine begins trying to run a spark from it's
** local stack.
*/
extern void MR_threadscope_post_looking_for_local_spark(void);

/*
** Post this message when a thread is about to attempt work stealing.
*/
extern void MR_threadscope_post_work_stealing(void);

/*
** Post this message before a parallel conjunction starts.
*/
extern void MR_threadscope_post_start_par_conj(MR_Word* dynamic_id,
                MR_TS_StringId static_id);

/*
** Post this message after a parallel conjunction stops.
*/
extern void MR_threadscope_post_end_par_conj(MR_Word* dynamic_id);

/*
** Post this message when a parallel conjunct calls the bariier code.
*/
extern void MR_threadscope_post_end_par_conjunct(MR_Word* dynamic_id);

/*
** Post this message when a future is created, this establishes the conjuction
** id to future id mapping.  The conjunction id is inferred by context.
** The name of the future within the conjunction is given by 'name'.
*/
extern void MR_threadscope_post_new_future(MR_Future* future_id, MR_TS_StringId name);

/*
** Post either of these messages when waiting on a future.  THe first if the
** context had to be suspended because the future was not available, and the
** second when the context did not need to be suspended.
*/
extern void MR_threadscope_post_wait_future_nosuspend(MR_Future* future_id);
extern void MR_threadscope_post_wait_future_suspended(MR_Future* future_id);

/*
** Post this event when signaling the production of a future.
*/
extern void MR_threadscope_post_signal_future(MR_Future* future_id);

/*
** Post this event when the engine is going to sleep.
*/
extern void MR_threadscope_post_engine_sleeping(void);

/*
** Register all the strings in an array and save their IDs in the array.
*/
extern void MR_threadscope_register_strings_array(MR_Threadscope_String *array,
                unsigned size);

/*
** Post a user-defined log message.
*/
extern void MR_threadscope_post_log_msg(const char *message);

#endif /* MR_THREADSCOPE */

#endif /* not MERCURY_THREADSCOPE_H */
