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A simple addition with significant performance implications:

Browse source 
sicslowpan tags TCP packets with the PACKETBUF_ATTR_PACKET_TYPE_STREAM
flag, which makes the underlying power-saving MAC layer keep the radio
on for some time after transmitting the packet. This allows reply
packets to be processed directly, significantly increasing TCP latency
and throughput.
This commit is contained in:
adamdunkels 2009-11-02 11:58:56 +00:00
parent 0a12f6da77
commit 5aab2eb77d
4 changed files with 133 additions and 34 deletions
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50
core/net/mac/lpp.c
View file

@ -28,7 +28,7 @@
*
* This file is part of the Contiki operating system.
*
* $Id: lpp.c,v 1.26 2009/10/19 11:25:54 nifi Exp $
* $Id: lpp.c,v 1.27 2009/11/02 11:58:56 adamdunkels Exp $
*/
/**
@ -79,6 +79,7 @@
#define WITH_ENCOUNTER_OPTIMIZATION 1
#define WITH_ADAPTIVE_OFF_TIME 0
#define WITH_PENDING_BROADCAST 1
#define WITH_STREAMING 1
#ifdef LPP_CONF_LISTEN_TIME
#define LISTEN_TIME LPP_CONF_LISTEN_TIME
@ -180,6 +181,13 @@ struct encounter {
#define MAX_ENCOUNTERS 4
LIST(encounter_list);
MEMB(encounter_memb, struct encounter, MAX_ENCOUNTERS);
#if WITH_STREAMING
static uint8_t is_streaming;
static struct ctimer stream_probe_timer, stream_off_timer;
#define STREAM_PROBE_TIME CLOCK_SECOND / 128
#define STREAM_OFF_TIME CLOCK_SECOND / 2
#endif /* WITH_STREAMING */
/*---------------------------------------------------------------------------*/
static void
turn_radio_on(void)
@ -191,7 +199,7 @@ turn_radio_on(void)
static void
turn_radio_off(void)
{
if(lpp_is_on) {
if(lpp_is_on && is_streaming == 0) {
radio->off();
}
/* leds_off(LEDS_YELLOW);*/
@ -247,6 +255,12 @@ turn_radio_on_callback(void *packet)
/* printf("enc\n");*/
}
/*---------------------------------------------------------------------------*/
static void
stream_off(void *dummy)
{
is_streaming = 0;
}
/*---------------------------------------------------------------------------*/
/* This function goes through all encounters to see if it finds a
matching neighbor. If so, we set a ctimer that will turn on the
radio just before we expect the neighbor to send a probe packet. If
@ -261,6 +275,18 @@ turn_radio_on_for_neighbor(rimeaddr_t *neighbor, struct queue_list_item *i)
{
struct encounter *e;
#if WITH_STREAMING
if(packetbuf_attr(PACKETBUF_ATTR_PACKET_TYPE) ==
PACKETBUF_ATTR_PACKET_TYPE_STREAM) {
is_streaming = 1;
turn_radio_on();
list_add(queued_packets_list, i);
ctimer_set(&stream_off_timer, STREAM_OFF_TIME,
stream_off, NULL);
return;
}
#endif /* WITH_STREAMING */
if(rimeaddr_cmp(neighbor, &rimeaddr_null)) {
#if ! WITH_PENDING_BROADCAST
/* We have been asked to turn on the radio for a broadcast, so we
@ -402,6 +428,19 @@ send_probe(void)
compower_accumulate(&compower_idle_activity);
}
/*---------------------------------------------------------------------------*/
static void
send_stream_probe(void *dummy)
{
/* Turn on the radio for sending a probe packet and
anticipating a data packet from a neighbor. */
turn_radio_on();
/* Send a probe packet. */
send_probe();
is_streaming = 1;
}
/*---------------------------------------------------------------------------*/
static int
num_packets_to_send(void)
{
@ -718,6 +757,13 @@ read_packet(void)
/* Send a probe packet to catch any reply from the other node. */
restart_dutycycle(PROBE_AFTER_TRANSMISSION_TIME);
#endif /* WITH_PROBE_AFTER_TRANSMISSION */
#if WITH_STREAMING
if(is_streaming) {
ctimer_set(&stream_probe_timer, STREAM_PROBE_TIME,
send_stream_probe, NULL);
}
#endif /* WITH_STREAMING */
}
#if WITH_ACK_OPTIMIZATION