X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/00001ff70f922b49f8c77737617d98f8d6f110e9..a3570625c9460617ccad1803b50bc4f1793b6376:/include/amok/bandwidth.h
diff --git a/include/amok/bandwidth.h b/include/amok/bandwidth.h
index ec2d1b6c70..295afbdd8a 100644
--- a/include/amok/bandwidth.h
+++ b/include/amok/bandwidth.h
@@ -10,81 +10,130 @@
#ifndef AMOK_BANDWIDTH_H
#define AMOK_BANDWIDTH_H
-#include "amok/base.h"
-
-/* module handling */
-
-
/** \addtogroup AMOK_bw
* \brief Test the bandwidth between two nodes
*
- * This module allows you to retrieve the bandwidth between to arbitrary hosts,
- * provided that they run some GRAS process which initialized this module.
- *
- * The API is very simple. Use amok_bw_test() to get the BW between the local host
- * and the specified peer, or amok_bw_request() to get the BW between two remote
- * hosts. The elapsed time, as long as the achieved bandwidth is returned in the
- * last arguments of the functions.
- *
- * All sizes are in kilo bytes.
+ * This module allows you to retrieve the bandwidth between to arbitrary hosts
+ * and saturating the links leading to them, provided that they run some GRAS
+ * process which initialized this module.
+ *
+ * \htmlonly Bandwidth measurement
\endhtmlonly
+ *
+ * Retrieving the bandwidth is usually done by active measurment: one send
+ * a packet of known size, time how long it needs to go back and forth,
+ * and you get the bandwidth in Kb/s available on the wire.
+ *
+ * This is not as easy as it first seems to do so in GRAS. The first issue
+ * is that GRAS messages can get buffered, or the receiver cannot be
+ * waiting for the message when it arrives. This results in extra delays
+ * impacting the measurement quality. You thus have to setup a rendez-vous
+ * protocol. The second issue is that GRAS message do have an header, so
+ * figuring out their size is not trivial. Moreover, they get converted
+ * when the sender and receiver processor architecture are different,
+ * inducing extra delays. For this, GRAS provide the so-called measurement
+ * sockets. On them, you can send raw data which is not converted (see
+ * \ref GRAS_sock_meas).
*
- * \todo Cleanup and implement the link saturation stuff.
+ * Solving all these problems is quite error prone and anoying, so we
+ * implemented this in the current module so that you don't have to do it
+ * yourself. The API is very simple. Use amok_bw_test() to get the BW
+ * between the local host and the specified peer, or amok_bw_request() to
+ * get the BW between two remote hosts. The elapsed time, as long as the
+ * achieved bandwidth is returned in the last arguments of the functions.
+ *
+ * All sizes are in bytes. The \a buf_size is the size of the buffer
+ * (this is a socket parameter set automatically). The \a exp_size is the
+ * amount of data to send during an experiment. \a msg_size is the size
+ * of each message sent. These values allow you to study phenomenon such
+ * as TCP slow start (which are not correctly modelized by \ref SURF_API,
+ * yet). They are mimicked from the NWS API, and default values could be
+ * buf_size=32k, msg_size=16k and exp_size=64k. That means that the
+ * socket will be prepared to accept 32k in its buffer and then four
+ * messages of 16k will be sent (so that the total amount of data equals
+ * 64k). Of course, you can use other values if you want to.
+ *
+ * \htmlonly
+ * 
+ * Fig 1: AMOK bandwidth measurement protocol.
+ * Link saturation
+ * \endhtmlonly
+ *
+ * You sometimes want to try saturating some link during the network
+ * related experiments (at least, we did ;). This also can turn quite
+ * untrivial to do, unless you use this great module. You can either ask
+ * for the saturation between the current host and a distant one with
+ * amok_bw_saturate_begin() or between two distant hosts with
+ * amok_bw_saturate_start(). In any case, remember that gras actors
+ * (processes) are not interruptible. It means that an actor you
+ * instructed to participate to a link saturation experiment will not do
+ * anything else until it is to its end (either because the asked duration
+ * was done or because someone used amok_bw_saturate_stop() on the emitter
+ * end of the experiment).
+ *
+ * The following figure depicts the used protocol. Note that any
+ * handshaking messages internal messages are omitted for sake of
+ * simplicity. In this example, the experiment ends before the planned
+ * experiment duration is over because one host use the
+ * amok_bw_saturate_stop() function, but things are not really different
+ * if the experiment stops alone. Also, it is not mandatory that the host
+ * calling amok_bw_saturate_stop() is the same than the one which called
+ * amok_bw_saturate_start(), despite what is depicted here.
+ *
+ * \htmlonly
+ * 
+ * Fig 2: AMOK link saturation protocol.
+ * \endhtmlonly
*
* @{
*/
-void amok_bw_init(void);
-void amok_bw_exit(void);
-
-xbt_error_t amok_bw_test(gras_socket_t peer,
- unsigned long int buf_size,unsigned long int exp_size,unsigned long int msg_size,
- /*OUT*/ double *sec, double *bw);
-
-xbt_error_t amok_bw_request(const char* from_name,unsigned int from_port,
- const char* to_name,unsigned int to_port,
- unsigned long int bufSize,unsigned long int expSize,unsigned long int msgSize,
- /*OUT*/ double *sec, double*bw);
+/* module handling */
-/** @} */
-#if 0
+XBT_PUBLIC(void) amok_bw_init(void);
+XBT_PUBLIC(void) amok_bw_exit(void);
+
+XBT_PUBLIC(void) amok_bw_test(gras_socket_t peer,
+ unsigned long int buf_size,
+ unsigned long int msg_size,
+ unsigned long int msg_amount,
+ double min_duration,
+ /*OUT*/ double *sec, double *bw);
+
+XBT_PUBLIC(void) amok_bw_request(const char *from_name,
+ unsigned int from_port, const char *to_name,
+ unsigned int to_port,
+ unsigned long int buf_size,
+ unsigned long int msg_size,
+ unsigned long int msg_amount,
+ double min_duration, /*OUT*/ double *sec,
+ double *bw);
+
+XBT_PUBLIC(double *) amok_bw_matrix(xbt_dynar_t hosts, /* dynar of xbt_host_t */
+ int buf_size_bw, int msg_size_bw,
+ int msg_amount_bw, double min_duration);
/* ***************************************************************************
* Link saturation
* ***************************************************************************/
-/**
- * grasbw_saturate_start:
- * @from_name: Name of the host we are asking to do a experiment with (to_name:to_port)
- * @from_port: port on which the process we are asking for an experiment is listening
- * (for message, do not give a raw socket here. The needed raw socket will be negociated
- * between the peers)
- * @to_name: Name of the host with which we should conduct the experiment
- * @to_port: port on which the peer process is listening for message
- * @msgSize: Size of each message sent.
- * @timeout: How long in maximum should be the saturation.
- *
- * Ask the process 'from_name:from_port' to start to saturate the link between itself
- * and to_name:to_name.
- */
-xbt_error_t grasbw_saturate_start(const char* from_name,unsigned int from_port,
- const char* to_name,unsigned int to_port,
- unsigned int msgSize, unsigned int timeout);
-
-/**
- * grasbw_saturate_stop:
- * @from_name: Name of the host we are asking to do a experiment with (to_name:to_port)
- * @from_port: port on which the process we are asking for an experiment is listening
- * (for message, do not give a raw socket here. The needed raw socket will be negociated
- * between the peers)
- * @to_name: Name of the host with which we should conduct the experiment
- * @to_port: port on which the peer process is listening for message
- *
- * Ask the process 'from_name:from_port' to stop saturating the link between itself
- * and to_name:to_name.
- */
-xbt_error_t grasbw_saturate_stop(const char* from_name,unsigned int from_port,
- const char* to_name,unsigned int to_port);
+XBT_PUBLIC(void) amok_bw_saturate_start(const char *from_name,
+ unsigned int from_port,
+ const char *to_name,
+ unsigned int to_port,
+ unsigned int msg_size,
+ double duration);
+
+XBT_PUBLIC(void) amok_bw_saturate_begin(const char *to_name,
+ unsigned int to_port,
+ unsigned int msg_size,
+ double duration,
+ /*out */ double *elapsed, double *bw);
+
+XBT_PUBLIC(void) amok_bw_saturate_stop(const char *from_name,
+ unsigned int from_port,
+ /*out */ double *time, double *bw);
+
+/** @} */
-#endif /* if 0 */
#endif /* AMOK_BANDWIDTH_H */