From: Martin Quinson <martin.quinson@loria.fr>
Date: Sun, 25 Dec 2011 17:40:47 +0000 (+0100)
Subject: Rename the TCP_gamma configuration option to network/TCP_gamma, and document it
X-Git-Tag: exp_20120216~231
X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/commitdiff_plain/2a61f9d5253f49aeb0d29bf205661e1a4cf40e69?hp=c5ba32dd93517cfb0defcff3551f8ac98e5f76e2

Rename the TCP_gamma configuration option to network/TCP_gamma, and document it
---

diff --git a/ChangeLog b/ChangeLog
index 1b4c255f4b..4356a57f17 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -14,6 +14,7 @@ SimGrid (3.7) NOT RELEASED; urgency=low
     --help-models for the list of all models and optimization modes.
   * The CLM03 workstation model were dropped for simplicity because it
     used the deprecated CM02 network model. Use default instead.
+  * Rename the TCP_gamma configuration option to network/TCP_gamma
   * Use now crosstraffic keyword instead of the terribly missleading 
     fullduplex keyword. Use --cfg=network/crosstraffic:1. This is
     activated by default now in the current default model.
diff --git a/doc/options.doc b/doc/options.doc
index 74ae3e8ac7..339fe7241a 100644
--- a/doc/options.doc
+++ b/doc/options.doc
@@ -137,7 +137,22 @@ variables). The accepted values are (both default to 'Lazy'):
     useful when debugging.
 
 
-\subsection options_simgrid_configuration_fullduplex Simulating cross-traffic
+\subsection options_model_network Configuring the Network model
+
+\subsubsection options_model_network_gamma Maximal TCP window size (network/TCP_gamma)
+
+The analytical models need to know the maximal TCP window size to take
+the TCP congestion mechanism into account. This is set to 20000 by
+default, but can be changed using the network/TCP_gamma variable.
+
+On linux, this value can be retrieved using the following
+commands. Both give a set of values, and you should use the last one,
+which is the maximal size.\verbatim
+cat /proc/sys/net/ipv4/tcp_rmem # gives the sender window
+cat /proc/sys/net/ipv4/tcp_wmem # gives the receiver window
+\endverbatim
+
+\subsubsection options_model_network_crosstraffic Simulating cross-traffic (network/crosstraffic)
 
 As of SimGrid v3.7, cross-traffic effects can be taken into account in
 analytical simulations. It means that ongoing and incoming
diff --git a/src/surf/surf_config.c b/src/surf/surf_config.c
index 733ff2b8df..d7c02d136a 100644
--- a/src/surf/surf_config.c
+++ b/src/surf/surf_config.c
@@ -379,14 +379,14 @@ void surf_config_init(int *argc, char **argv)
                      "Model to use to store the routing information",
                      xbt_cfgelm_string, &default_value, 1, 1, NULL, NULL);
 
-    xbt_cfg_register(&_surf_cfg_set, "TCP_gamma",
+    xbt_cfg_register(&_surf_cfg_set, "network/TCP_gamma",
                      "Size of the biggest TCP window (cat /proc/sys/net/ipv4/tcp_[rw]mem for recv/send window; Use the last given value, which is the max window size)",
                      xbt_cfgelm_double, NULL, 1, 1,
                      _surf_cfg_cb__tcp_gamma, NULL);
-    xbt_cfg_setdefault_double(_surf_cfg_set, "TCP_gamma", 20000.0);
+    xbt_cfg_setdefault_double(_surf_cfg_set, "network/TCP_gamma", 20000.0);
 
     xbt_cfg_register(&_surf_cfg_set, "maxmin/precision",
-                     "Minimum retained action value when updating simulation",
+                     "Minimum retained action value when updating simulation (similar to numerical precision)",
                      xbt_cfgelm_double, NULL, 1, 1, _surf_cfg_cb__maxmin_precision, NULL);
     xbt_cfg_setdefault_double(_surf_cfg_set, "maxmin/precision", 0.00001); // FIXME use setdefault everywhere here!