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netsim: add token bucket algorithm for simulating network congestion

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Havard Graff 2017-11-23 13:47:48 +01:00 committed by Tim-Philipp Müller
parent 3cdd53621e
commit 3eb733d95f
2 changed files with 149 additions and 4 deletions
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146
gst/netsim/gstnetsim.c
View file

@ -4,7 +4,7 @@
* Copyright 2006 Collabora Ltd,
* Copyright 2006 Nokia Corporation
* @author: Philippe Kalaf <philippe.kalaf@collabora.co.uk>.
* Copyright 2012-2015 Pexip
* Copyright 2012-2016 Pexip
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
@ -42,6 +42,8 @@ enum
PROP_DROP_PROBABILITY,
PROP_DUPLICATE_PROBABILITY,
PROP_DROP_PACKETS,
PROP_MAX_KBPS,
PROP_MAX_BUCKET_SIZE,
};
/* these numbers are nothing but wild guesses and dont reflect any reality */
@ -51,6 +53,8 @@ enum
#define DEFAULT_DROP_PROBABILITY 0.0
#define DEFAULT_DUPLICATE_PROBABILITY 0.0
#define DEFAULT_DROP_PACKETS 0
#define DEFAULT_MAX_KBPS -1
#define DEFAULT_MAX_BUCKET_SIZE -1
static GstStaticPadTemplate gst_net_sim_sink_template =
GST_STATIC_PAD_TEMPLATE ("sink",
@ -221,12 +225,105 @@ gst_net_sim_delay_buffer (GstNetSim * netsim, GstBuffer * buf)
return ret;
}
static gsize
get_buffer_size_in_bits (GstBuffer * buf)
{
GstMapInfo map = GST_MAP_INFO_INIT;
gsize size;
gst_buffer_map (buf, &map, GST_MAP_READ);
size = map.size * 8;
gst_buffer_unmap (buf, &map);
return size;
}
static gint
gst_net_sim_get_tokens (GstNetSim * netsim)
{
gint tokens = 0;
GstClockTimeDiff elapsed_time = 0;
GstClockTime current_time = 0;
GstClockTimeDiff token_time;
GstClock *clock;
/* check for umlimited kbps and fill up the bucket if that is the case,
* if not, calculate the number of tokens to add based on the elapsed time */
if (netsim->max_kbps == -1)
return netsim->max_bucket_size * 1000 - netsim->bucket_size;
/* get the current time */
clock = gst_element_get_clock (GST_ELEMENT_CAST (netsim));
if (clock == NULL) {
GST_WARNING_OBJECT (netsim, "No clock, can't get the time");
} else {
current_time = gst_clock_get_time (clock);
}
/* get the elapsed time */
if (GST_CLOCK_TIME_IS_VALID (netsim->prev_time)) {
if (current_time < netsim->prev_time) {
GST_WARNING_OBJECT (netsim, "Clock is going backwards!!");
} else {
elapsed_time = GST_CLOCK_DIFF (netsim->prev_time, current_time);
}
} else {
netsim->prev_time = current_time;
}
/* calculate number of tokens and how much time is "spent" by these tokens */
tokens =
gst_util_uint64_scale_int (elapsed_time, netsim->max_kbps * 1000,
GST_SECOND);
token_time =
gst_util_uint64_scale_int (GST_SECOND, tokens, netsim->max_kbps * 1000);
/* increment the time with how much we spent in terms of whole tokens */
netsim->prev_time += token_time;
gst_object_unref (clock);
return tokens;
}
static gboolean
gst_net_sim_token_bucket (GstNetSim * netsim, GstBuffer * buf)
{
gsize buffer_size;
gint tokens;
/* with an unlimited bucket-size, we have nothing to do */
if (netsim->max_bucket_size == -1)
return TRUE;
buffer_size = get_buffer_size_in_bits (buf);
tokens = gst_net_sim_get_tokens (netsim);
netsim->bucket_size = MIN (G_MAXINT, netsim->bucket_size + tokens);
GST_LOG_OBJECT (netsim, "Adding %d tokens to bucket (contains %lu tokens)",
tokens, netsim->bucket_size);
if (netsim->max_bucket_size != -1 && netsim->bucket_size >
netsim->max_bucket_size * 1000)
netsim->bucket_size = netsim->max_bucket_size * 1000;
if (buffer_size > netsim->bucket_size) {
GST_DEBUG_OBJECT (netsim, "Buffer size (%lu) exeedes bucket size (%lu)",
buffer_size, netsim->bucket_size);
return FALSE;
}
netsim->bucket_size -= buffer_size;
GST_LOG_OBJECT (netsim, "Buffer taking %lu tokens (%lu left)",
buffer_size, netsim->bucket_size);
return TRUE;
}
static GstFlowReturn
gst_net_sim_chain (GstPad * pad, GstObject * parent, GstBuffer * buf)
{
GstNetSim *netsim = GST_NET_SIM (parent);
GstFlowReturn ret = GST_FLOW_OK;
if (!gst_net_sim_token_bucket (netsim, buf))
goto done;
if (netsim->drop_packets > 0) {
netsim->drop_packets--;
GST_DEBUG_OBJECT (netsim, "Dropping packet (%d left)",
@ -245,8 +342,8 @@ gst_net_sim_chain (GstPad * pad, GstObject * parent, GstBuffer * buf)
ret = gst_net_sim_delay_buffer (netsim, buf);
}
done:
gst_buffer_unref (buf);
return ret;
}
@ -276,6 +373,14 @@ gst_net_sim_set_property (GObject * object,
case PROP_DROP_PACKETS:
netsim->drop_packets = g_value_get_uint (value);
break;
case PROP_MAX_KBPS:
netsim->max_kbps = g_value_get_int (value);
break;
case PROP_MAX_BUCKET_SIZE:
netsim->max_bucket_size = g_value_get_int (value);
if (netsim->max_bucket_size != -1)
netsim->bucket_size = netsim->max_bucket_size * 1000;
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
@ -307,6 +412,12 @@ gst_net_sim_get_property (GObject * object,
case PROP_DROP_PACKETS:
g_value_set_uint (value, netsim->drop_packets);
break;
case PROP_MAX_KBPS:
g_value_set_int (value, netsim->max_kbps);
break;
case PROP_MAX_BUCKET_SIZE:
g_value_set_int (value, netsim->max_bucket_size);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
@ -329,6 +440,7 @@ gst_net_sim_init (GstNetSim * netsim)
g_cond_init (&netsim->start_cond);
netsim->rand_seed = g_rand_new ();
netsim->main_loop = NULL;
netsim->prev_time = GST_CLOCK_TIME_NONE;
GST_OBJECT_FLAG_SET (netsim->sinkpad,
GST_PAD_FLAG_PROXY_CAPS | GST_PAD_FLAG_PROXY_ALLOCATION);
@ -377,7 +489,8 @@ gst_net_sim_class_init (GstNetSimClass * klass)
"Filter/Network",
"An element that simulates network jitter, "
"packet loss and packet duplication",
"Philippe Kalaf <philippe.kalaf@collabora.co.uk>");
"Philippe Kalaf <philippe.kalaf@collabora.co.uk>, "
"Havard Graff <havard@pexip.com>");
gobject_class->dispose = GST_DEBUG_FUNCPTR (gst_net_sim_dispose);
gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_net_sim_finalize);
@ -420,6 +533,33 @@ gst_net_sim_class_init (GstNetSimClass * klass)
"Drop the next n packets",
0, G_MAXUINT, DEFAULT_DROP_PACKETS,
G_PARAM_READWRITE | G_PARAM_CONSTRUCT | G_PARAM_STATIC_STRINGS));
/**
* GstNetSim:max-kbps:
*
* The maximum number of kilobits to let through per second. Setting this
* property to a positive value enables network congestion simulation using
* a token bucket algorithm. Also see the "max-bucket-size" property,
*
* Since: 1.14
*/
g_object_class_install_property (gobject_class, PROP_MAX_KBPS,
g_param_spec_int ("max-kbps", "Maximum Kbps",
"The maximum number of kilobits to let through per second "
"(-1 = unlimited)", -1, G_MAXINT, DEFAULT_MAX_KBPS,
G_PARAM_READWRITE | G_PARAM_CONSTRUCT | G_PARAM_STATIC_STRINGS));
/**
* GstNetSim:max-bucket-size:
*
* The size of the token bucket, related to burstiness resilience.
*
* Since: 1.14
*/
g_object_class_install_property (gobject_class, PROP_MAX_BUCKET_SIZE,
g_param_spec_int ("max-bucket-size", "Maximum Bucket Size (Kb)",
"The size of the token bucket, related to burstiness resilience "
"(-1 = unlimited)", -1, G_MAXINT, DEFAULT_MAX_BUCKET_SIZE,
G_PARAM_READWRITE | G_PARAM_CONSTRUCT | G_PARAM_STATIC_STRINGS));
GST_DEBUG_CATEGORY_INIT (netsim_debug, "netsim", 0, "Network simulator");
}

7
gst/netsim/gstnetsim.h
View file

@ -57,14 +57,19 @@ struct _GstNetSim
GCond start_cond;
GMainLoop *main_loop;
gboolean running;
GRand *rand_seed;
gsize bucket_size;
GstClockTime prev_time;
/* properties */
gint min_delay;
gint max_delay;
gfloat delay_probability;
gfloat drop_probability;
gfloat duplicate_probability;
guint drop_packets;
gint max_kbps;
gint max_bucket_size;
};
struct _GstNetSimClass