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improve debugging output. introduce GetBackoffStartFor and GetBackoffEndFor

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This commit is contained in:
Mathieu Lacage
2007-11-14 13:50:19 +01:00
parent 5b47785ae4
commit dada8dc1db
2 changed files with 55 additions and 44 deletions
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97
src/devices/wifi/dcf-manager.cc
View File

@@ -10,6 +10,9 @@
NS_LOG_COMPONENT_DEFINE ("DcfManager");
#define MY_DEBUG(x) \
NS_LOG_DEBUG (Simulator::Now () << " " x)
namespace ns3 {
/****************************************************************
@@ -185,7 +188,7 @@ DcfManager::RequestAccess (DcfState *state)
/* we don't need to do anything because we have an access
* timer which will expire soon.
*/
NS_LOG_DEBUG ("access timer running. will be notified");
MY_DEBUG ("access timer running. will be notified");
return;
}
/**
@@ -196,7 +199,7 @@ DcfManager::RequestAccess (DcfState *state)
if (state->GetBackoffSlots () == 0 &&
IsBusy ())
{
NS_LOG_DEBUG ("medium is busy: collision");
MY_DEBUG ("medium is busy: collision");
/* someone else has accessed the medium.
* generate a backoff.
*/
@@ -210,26 +213,30 @@ DcfManager::RequestAccess (DcfState *state)
void
DcfManager::DoGrantAccess (void)
{
Time accessGrantStart = GetAccessGrantStart ();
uint32_t k = 0;
for (States::const_iterator i = m_states.begin (); i != m_states.end (); k++)
{
DcfState *state = *i;
if (state->GetBackoffSlots () == 0 && state->NeedsAccess ())
if (state->GetBackoffSlots () == 0 && state->NeedsAccess () &&
GetBackoffStartFor (state) < Simulator::Now ())
{
/**
* This is the first dcf we find with an expired backoff and which
* needs access to the medium. i.e., it has data to send.
*/
NS_LOG_DEBUG ("dcf " << k << " needs access. backoff expired. access granted.");
MY_DEBUG ("dcf " << k << " needs access. backoff expired. access granted.");
state->NotifyAccessGranted ();
i++; // go to the next item in the list.
k++;
for (States::const_iterator j = i; j != m_states.end (); j++, k++)
{
DcfState *state = *j;
if (state->GetBackoffSlots () == 0 && state->NeedsAccess ())
if (state->GetBackoffSlots () == 0 && state->NeedsAccess () &&
GetBackoffStartFor (state) < Simulator::Now ())
{
NS_LOG_DEBUG ("dcf " << k << " needs access. backoff expired. internal collision.");
MY_DEBUG ("dcf " << k << " needs access. backoff expired. internal collision.");
/**
* all other dcfs with a lower priority whose backoff
* has expired and which needed access to the medium
@@ -276,7 +283,7 @@ DcfManager::GetAccessGrantStart (void) const
busyAccessStart,
txAccessStart,
navAccessStart);
NS_LOG_DEBUG ("access grant start=" << accessGrantedStart <<
MY_DEBUG ("access grant start=" << accessGrantedStart <<
", rx access start=" << rxAccessStart <<
", busy access start=" << busyAccessStart <<
", tx access start=" << txAccessStart <<
@@ -284,6 +291,21 @@ DcfManager::GetAccessGrantStart (void) const
return accessGrantedStart;
}
Time
DcfManager::GetBackoffStartFor (DcfState *state)
{
Time mostRecentEvent = MostRecent (state->GetBackoffStart (),
GetAccessGrantStart () + Scalar (state->GetAifsn ()) * m_slotTime);
return mostRecentEvent;
}
Time
DcfManager::GetBackoffEndFor (DcfState *state)
{
return GetBackoffStartFor (state) + Scalar (state->GetBackoffSlots ()) * m_slotTime;
}
void
DcfManager::UpdateBackoff (void)
{
@@ -292,11 +314,11 @@ DcfManager::UpdateBackoff (void)
{
DcfState *state = *i;
Time mostRecentEvent = MostRecent (state->GetBackoffStart (),
GetAccessGrantStart ());
if (mostRecentEvent < Simulator::Now ())
Time backoffStart = GetBackoffStartFor (state);
if (backoffStart <= Simulator::Now ())
{
Scalar nSlots = (Simulator::Now () - mostRecentEvent) / m_slotTime;
Scalar nSlots = (Simulator::Now () - backoffStart) / m_slotTime;
// XXX: rounding should be nicer.
uint32_t nIntSlots = lrint (nSlots.GetDouble ());
/**
* For each DcfState, calculate how many backoff slots elapsed since
@@ -306,8 +328,8 @@ DcfManager::UpdateBackoff (void)
*/
if (nIntSlots > state->GetAifsn ())
{
NS_LOG_DEBUG ("dcf " << k << " dec backoff slots=" << nIntSlots - state->GetAifsn ());
state->UpdateBackoffSlotsNow (nIntSlots - state->GetAifsn ());
MY_DEBUG ("dcf " << k << " dec backoff slots=" << nIntSlots);
state->UpdateBackoffSlotsNow (nIntSlots);
}
}
}
@@ -321,25 +343,19 @@ DcfManager::DoRestartAccessTimeoutIfNeeded (void)
* if there is one, how many slots for AIFS+backoff does it require ?
*/
bool accessTimeoutNeeded = false;
uint32_t minNSlots = 0xffffffff;
Time backoffStart;
Time expectedBackoffEnd = MaxSeconds ();
for (States::const_iterator i = m_states.begin (); i != m_states.end (); i++)
{
DcfState *state = *i;
if (state->NeedsAccess ())
{
accessTimeoutNeeded = true;
minNSlots = std::min (state->GetAifsn () + state->GetBackoffSlots (), minNSlots);
expectedBackoffEnd = std::min (expectedBackoffEnd, GetBackoffEndFor (state));
}
}
if (accessTimeoutNeeded)
{
/**
* If one of the DcfState needs access to the medium, calculate when its
* backoff is expected to end.
*/
Time expectedBackoffEnd = GetAccessGrantStart () + Scalar (minNSlots) * m_slotTime;
NS_LOG_DEBUG ("min n slots=" << minNSlots << ", expected backoff end="<<expectedBackoffEnd);
MY_DEBUG ("expected backoff end="<<expectedBackoffEnd);
/**
* It is not possible that the backoff was expected to end before now
* because if it were possible, this would mean that we have missed
@@ -366,56 +382,50 @@ DcfManager::DoRestartAccessTimeoutIfNeeded (void)
void
DcfManager::NotifyRxStartNow (Time duration)
{
Time now = Simulator::Now ();
NS_LOG_DEBUG ("rx start at="<<now<<", for="<<duration);
MY_DEBUG ("rx start for="<<duration);
UpdateBackoff ();
m_lastRxStart = now;
m_lastRxStart = Simulator::Now ();
m_lastRxDuration = duration;
m_rxing = true;
}
void
DcfManager::NotifyRxEndOkNow (void)
{
Time now = Simulator::Now ();
NS_LOG_DEBUG ("rx end ok at="<<now);
m_lastRxEnd = now;
MY_DEBUG ("rx end ok");
m_lastRxEnd = Simulator::Now ();
m_lastRxReceivedOk = true;
m_rxing = false;
}
void
DcfManager::NotifyRxEndErrorNow (void)
{
Time now = Simulator::Now ();
NS_LOG_DEBUG ("rx end error at=");
m_lastRxEnd = now;
MY_DEBUG ("rx end error");
m_lastRxEnd = Simulator::Now ();
m_lastRxReceivedOk = false;
m_rxing = false;
}
void
DcfManager::NotifyTxStartNow (Time duration)
{
Time now = Simulator::Now ();
NS_LOG_DEBUG ("tx start at="<<now<<" for "<<duration);
MY_DEBUG ("tx start for "<<duration);
UpdateBackoff ();
m_lastTxStart = now;
m_lastTxStart = Simulator::Now ();
m_lastTxDuration = duration;
}
void
DcfManager::NotifyCcaBusyStartNow (Time duration)
{
Time now = Simulator::Now ();
NS_LOG_DEBUG ("busy start at="<<now<<" for "<<duration);
MY_DEBUG ("busy start for "<<duration);
UpdateBackoff ();
m_lastBusyStart = now;
m_lastBusyStart = Simulator::Now ();
m_lastBusyDuration = duration;
}
void
DcfManager::NotifyNavResetNow (Time duration)
{
Time now = Simulator::Now ();
NS_LOG_DEBUG ("nav reset at="<<now<<", for="<<duration);
MY_DEBUG ("nav reset for="<<duration);
UpdateBackoff ();
m_lastNavStart = now;
m_lastNavStart = Simulator::Now ();
m_lastNavDuration = duration;
UpdateBackoff ();
/**
@@ -429,12 +439,11 @@ DcfManager::NotifyNavResetNow (Time duration)
void
DcfManager::NotifyNavStartNow (Time duration)
{
Time now = Simulator::Now ();
NS_ASSERT (m_lastNavStart < now);
NS_LOG_DEBUG ("nav start at="<<now<<", for="<<duration);
NS_ASSERT (m_lastNavStart < Simulator::Now ());
MY_DEBUG ("nav start for="<<duration);
UpdateBackoff ();
// XXX handle
m_lastNavStart = now;
m_lastNavStart = Simulator::Now ();
m_lastNavDuration = duration;
}

2
src/devices/wifi/dcf-manager.h
View File

@@ -117,6 +117,8 @@ private:
* be granted
*/
Time GetAccessGrantStart (void) const;
Time GetBackoffStartFor (DcfState *state);
Time GetBackoffEndFor (DcfState *state);
void DoRestartAccessTimeoutIfNeeded (void);
void AccessTimeout (void);
void DoGrantAccess (void);