gvt.c File Reference

Global Virtual Time. More...

#include <gvt/gvt.h>
#include <arch/timer.h>
#include <core/sync.h>
#include <datatypes/msg_queue.h>
#include <distributed/mpi.h>
#include <memory.h>
#include <stdatomic.h>

Include dependency graph for gvt.c:

Enumerations
enum	thread_phase {   thread_phase_idle = 0 , thread_phase_A , thread_phase_B , thread_phase_C ,   thread_phase_D }
	A thread phase during the gvt algorithm computation.
enum	node_phase {   node_phase_redux_first = 0 , node_sent_reduce , node_sent_reduce_wait , node_sent_wait ,   node_phase_redux_second , node_min_reduce , node_min_reduce_wait , node_min_wait ,   node_done }
	Node phases of the non-blocking GVT algorithm.

Functions
void	gvt_global_init (void)
	Initializes the gvt module in the node.
void	gvt_start_processing (void)
	Handles a MSG_CTRL_GVT_START control message. More...
void	gvt_on_done_ctrl_msg (void)
	Handles a MSG_CTRL_GVT_DONE control message. More...
void	gvt_on_msg_extraction (simtime_t msg_t)
	Informs the GVT subsystem that a new message is being processed. More...
static simtime_t	gvt_node_reduce (void)
static bool	gvt_thread_phase_run (void)
static bool	gvt_node_phase_run (void)
simtime_t	gvt_phase_run (void)
	Executes a step of the GVT algorithm. More...
void	gvt_msg_drain (void)
	Cleanup the distributed state of the GVT algorithm. More...
void	gvt_remote_msg_send (struct lp_msg *msg, nid_t dest_nid)
void	gvt_remote_anti_msg_send (struct lp_msg *msg, nid_t dest_nid)
void	gvt_remote_msg_receive (struct lp_msg *msg)
void	gvt_remote_anti_msg_receive (struct lp_msg *msg)

Variables
static __thread enum thread_phase	thread_phase = thread_phase_idle
static timer_uint	gvt_timer
static simtime_t	reducing_p [MAX_THREADS]
static __thread simtime_t	gvt_accumulator
static _Atomic rid_t	c_a = 0
static _Atomic rid_t	c_b = 0
static _Atomic nid_t	gvt_nodes
__thread _Bool	gvt_phase
__thread uint32_t	remote_msg_seq [2][MAX_NODES]
__thread uint32_t	remote_msg_received [2]

Detailed Description

Global Virtual Time.

For a detailed explanantion of the algorithm, see:

T. Tocci, A. Pellegrini, F. Quaglia, J. Casanovas-García, and T. Suzumura “ORCHESTRA: An Asynchronous Wait-Free Distributed GVT Algorithm” in Proceedings of the 21st IEEE/ACM International Symposium on Distributed Simulation and Real Time Applications, 2017, pp. 51–58

Copyright

Copyright (C) 2008-2022 HPDCS Group https://hpdcs.github.io

Function Documentation

gvt_msg_drain()

gvt_msg_drain

(

void

)

Cleanup the distributed state of the GVT algorithm.

This function flushes the remaining remote messages, moreover it makes sure that all the nodes complete the potentially ongoing GVT algorithm so that MPI collectives are inactive.

gvt_on_done_ctrl_msg()

void gvt_on_done_ctrl_msg

(

void

)

Handles a MSG_CTRL_GVT_DONE control message.

Called by the MPI layer in response to a MSG_CTRL_GVT_DONE control message

gvt_on_msg_extraction()

void gvt_on_msg_extraction

(

simtime_t

msg_t

)

Informs the GVT subsystem that a new message is being processed.

Parameters

msg_t

the timestamp of the message being processed

Called by the process layer when processing a new message; used in the actual GVT calculation

gvt_phase_run()

gvt_phase_run

(

void

)

Executes a step of the GVT algorithm.

Returns

the latest GVT value or 0.0 if the algorithm must still complete

This function must be called several times by all the processing threads hosted in the nodes involved in the simulation before completing and returning a proper GVT value.

gvt_remote_anti_msg_receive()

void gvt_remote_anti_msg_receive

(

struct lp_msg *

msg

)

Registers an incoming remote anti-message in the GVT subsystem

Parameters

msg	the remote anti-message to register

gvt_remote_anti_msg_send()

void gvt_remote_anti_msg_send	(	struct lp_msg *	msg,
		nid_t	dest_nid
	)

Registers an outgoing remote anti-message in the GVT subsystem

Parameters

msg	the remote anti-message to register
dest_nid	the destination node id of the anti-message

gvt_remote_msg_receive()

void gvt_remote_msg_receive

(

struct lp_msg *

msg

)

Registers an incoming remote message in the GVT subsystem

Parameters

msg	the remote message to register

gvt_remote_msg_send()

void gvt_remote_msg_send	(	struct lp_msg *	msg,
		nid_t	dest_nid
	)

Registers an outgoing remote message in the GVT subsystem

Parameters

msg	the remote message to register
dest_nid	the destination node id of the message

gvt_start_processing()

void gvt_start_processing

(

void

)

Handles a MSG_CTRL_GVT_START control message.

Called by the MPI layer in response to a MSG_CTRL_GVT_START control message, but also internally to start a new reduction