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search timer now uses a private lock

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This commit is contained in:
Jeff Hill
2002-06-17 15:18:58 +00:00
parent 36b061fa2f
commit c8095b4edc
3 changed files with 111 additions and 108 deletions
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207
src/ca/searchTimer.cpp
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@@ -34,11 +34,10 @@ static const double maxSearchPeriod = 5.0; // seconds
//
// searchTimer::searchTimer ()
//
searchTimer::searchTimer ( udpiiu &iiuIn, epicsTimerQueue &queueIn, udpMutex &mutexIn ) :
searchTimer::searchTimer ( udpiiu &iiuIn, epicsTimerQueue &queueIn ) :
period ( initialRoundTripEstimate * 2.0 ),
roundTripDelayEstimate ( initialRoundTripEstimate ),
timer ( queueIn.createTimer () ),
mutex ( mutexIn ),
iiu ( iiuIn ),
framesPerTry ( initialTriesPerFrame ),
framesPerTryCongestThresh ( UINT_MAX ),
@@ -46,7 +45,7 @@ searchTimer::searchTimer ( udpiiu &iiuIn, epicsTimerQueue &queueIn, udpMutex &mu
retry ( 0u ),
searchAttempts ( 0u ),
searchResponses ( 0u ),
searchAttemptsThisPass ( 0u ),
searchAttemptsThisPass ( 0u ),
searchResponsesThisPass ( 0u ),
retrySeqNo ( 0u ),
retrySeqAtPassBegin ( 0u ),
@@ -65,10 +64,13 @@ searchTimer::~searchTimer ()
//
void searchTimer::resetPeriod ( double delayToNextTry )
{
bool start;
if ( this->iiu.channelCount() == 0 ) {
return;
}
bool start;
{
epicsGuard < udpMutex > locker ( this->mutex );
epicsGuard < searchTimerMutex > locker ( this->mutex );
// upper bound
double newPeriod = this->roundTripDelayEstimate * 2.0;
@@ -81,24 +83,19 @@ void searchTimer::resetPeriod ( double delayToNextTry )
}
this->retry = 0;
if ( this->iiu.channelCount() > 0 ) {
if ( ! this->active ) {
if ( ! this->active ) {
this->active = true;
this->noDelay = ( delayToNextTry == 0.0 );
start = true;
}
else if ( this->period > newPeriod ) {
double delay = this->timer.getExpireDelay();
if ( delay > newPeriod ) {
this->active = true;
this->noDelay = ( delayToNextTry == 0.0 );
delayToNextTry = newPeriod;
start = true;
}
else if ( this->period > newPeriod ) {
double delay = this->timer.getExpireDelay();
if ( delay > newPeriod ) {
this->active = true;
this->noDelay = ( delayToNextTry == 0.0 );
delayToNextTry = newPeriod;
start = true;
}
else {
start = false;
}
}
else {
start = false;
}
@@ -106,7 +103,6 @@ void searchTimer::resetPeriod ( double delayToNextTry )
else {
start = false;
}
this->period = newPeriod;
}
@@ -157,7 +153,7 @@ void searchTimer::notifySearchResponse ( unsigned short retrySeqNoIn,
bool reschedualNeeded = false;
{
epicsGuard < udpMutex > locker ( this->mutex );
epicsGuard < searchTimerMutex > locker ( this->mutex );
if ( this->retrySeqAtPassBegin <= retrySeqNoIn ) {
if ( this->searchResponses < UINT_MAX ) {
@@ -203,105 +199,102 @@ void searchTimer::notifySearchResponse ( unsigned short retrySeqNoIn,
//
epicsTimerNotify::expireStatus searchTimer::expire ( const epicsTime & currentTime ) // X aCC 361
{
epicsGuard < udpMutex > locker ( this->mutex );
unsigned nFrameSent = 0u;
unsigned nChanSent = 0u;
/*
* check to see if there is nothing to do here
*/
// check to see if there is nothing to do here
if ( this->iiu.channelCount () == 0 ) {
debugPrintf ( ( "all channels located - search timer terminating\n" ) );
epicsGuard < searchTimerMutex > locker ( this->mutex );
this->active = false;
this->noDelay = false;
debugPrintf ( ( "all channels located - search timer terminating\n" ) );
return noRestart;
}
if ( ! this->noDelay ) {
debugPrintf ( ( "timed out waiting for a response\n" ) );
}
{
if ( ! this->noDelay ) {
debugPrintf ( ( "timed out waiting for a response\n" ) );
}
/*
* increment the retry sequence number
*/
this->retrySeqNo++; /* allowed to roll over */ // X aCC 818
this->timeAtLastRetry = currentTime;
/*
* dynamically adjust the number of UDP frames per
* try depending how many search requests are not
* replied to
*
* This determines how many search request can be
* sent together (at the same instant in time).
*
* The variable this->framesPerTry
* determines the number of UDP frames to be sent
* each time that expire() is called.
* If this value is too high we will waste some
* network bandwidth. If it is too low we will
* use very little of the incoming UDP message
* buffer associated with the server's port and
* will therefore take longer to connect. We
* initialize this->framesPerTry
* to a prime number so that it is less likely that the
* same channel is in the last UDP frame
* sent every time that this is called (and
* potentially discarded by a CA server with
* a small UDP input queue).
*/
/*
* increase frames per try only if we see better than
* a 93.75% success rate for one pass through the list
*/
if ( this->searchResponses >
( this->searchAttempts - (this->searchAttempts/16u) ) ) {
/*
* increase UDP frames per try if we have a good score
*/
if ( this->framesPerTry < maxTriesPerFrame ) {
* increment the retry sequence number
*/
this->retrySeqNo++; /* allowed to roll over */ // X aCC 818
this->timeAtLastRetry = currentTime;
/*
* dynamically adjust the number of UDP frames per
* try depending how many search requests are not
* replied to
*
* This determines how many search request can be
* sent together (at the same instant in time).
*
* The variable this->framesPerTry
* determines the number of UDP frames to be sent
* each time that expire() is called.
* If this value is too high we will waste some
* network bandwidth. If it is too low we will
* use very little of the incoming UDP message
* buffer associated with the server's port and
* will therefore take longer to connect. We
* initialize this->framesPerTry
* to a prime number so that it is less likely that the
* same channel is in the last UDP frame
* sent every time that this is called (and
* potentially discarded by a CA server with
* a small UDP input queue).
*/
/*
* increase frames per try only if we see better than
* a 93.75% success rate for one pass through the list
*/
if ( this->searchResponses >
( this->searchAttempts - (this->searchAttempts/16u) ) ) {
/*
* a congestion avoidance threshold similar to TCP is now used
*/
if ( this->framesPerTry < this->framesPerTryCongestThresh ) {
this->framesPerTry += this->framesPerTry;
* increase UDP frames per try if we have a good score
*/
if ( this->framesPerTry < maxTriesPerFrame ) {
/*
* a congestion avoidance threshold similar to TCP is now used
*/
if ( this->framesPerTry < this->framesPerTryCongestThresh ) {
this->framesPerTry += this->framesPerTry;
}
else {
this->framesPerTry += (this->framesPerTry/8) + 1;
}
debugPrintf ( ("Increasing frame count to %u t=%u r=%u\n",
this->framesPerTry, this->searchAttempts, this->searchResponses) );
}
else {
this->framesPerTry += (this->framesPerTry/8) + 1;
}
// if we detect congestion because we have less than a 87.5% success
// rate then gradually reduce the frames per try
else if ( this->searchResponses <
( this->searchAttempts - (this->searchAttempts/8u) ) ) {
if ( this->framesPerTry > 1 ) {
this->framesPerTry--;
}
debugPrintf ( ("Increasing frame count to %u t=%u r=%u\n",
this->framesPerTryCongestThresh = this->framesPerTry/2 + 1;
debugPrintf ( ("Congestion detected - set frames per try to %u t=%u r=%u\n",
this->framesPerTry, this->searchAttempts, this->searchResponses) );
}
}
/*
* if we detect congestion because we have less than a 87.5% success
* rate then gradually reduce the frames per try
*/
else if ( this->searchResponses <
( this->searchAttempts - (this->searchAttempts/8u) ) ) {
if (this->framesPerTry>1) {
this->framesPerTry--;
if ( this->searchAttemptsThisPass <= UINT_MAX - this->searchAttempts ) {
this->searchAttemptsThisPass += this->searchAttempts;
}
this->framesPerTryCongestThresh = this->framesPerTry/2 + 1;
debugPrintf ( ("Congestion detected - set frames per try to %u t=%u r=%u\n",
this->framesPerTry, this->searchAttempts, this->searchResponses) );
else {
this->searchAttemptsThisPass = UINT_MAX;
}
if ( this->searchResponsesThisPass <= UINT_MAX - this->searchResponses ) {
this->searchResponsesThisPass += this->searchResponses;
}
else {
this->searchResponsesThisPass = UINT_MAX;
}
this->searchAttempts = 0;
this->searchResponses = 0;
}
if ( this->searchAttemptsThisPass <= UINT_MAX - this->searchAttempts ) {
this->searchAttemptsThisPass += this->searchAttempts;
}
else {
this->searchAttemptsThisPass = UINT_MAX;
}
if ( this->searchResponsesThisPass <= UINT_MAX - this->searchResponses ) {
this->searchResponsesThisPass += this->searchResponses;
}
else {
this->searchResponsesThisPass = UINT_MAX;
}
this->searchAttempts = 0;
this->searchResponses = 0;
unsigned nChanSent = 0u;
unsigned nFrameSent = 0u;
while ( true ) {
/*
@@ -314,6 +307,7 @@ epicsTimerNotify::expireStatus searchTimer::expire ( const epicsTime & currentTi
if ( this->searchAttemptsThisPass >= this->iiu.channelCount () ) {
if ( this->searchResponsesThisPass == 0u ) {
debugPrintf ( ("increasing search try interval\n") );
epicsGuard < searchTimerMutex > locker ( this->mutex );
this->setRetryInterval ( this->minRetry + 1u );
}
@@ -368,7 +362,7 @@ epicsTimerNotify::expireStatus searchTimer::expire ( const epicsTime & currentTi
/*
* dont send any of the channels twice within one try
*/
if ( nChanSent >= this->iiu.channelCount () ) {
if ( nChanSent >= this->iiu.channelCount () ) {
/*
* add one to nFrameSent because there may be
* one more partial frame to be sent
@@ -402,16 +396,19 @@ epicsTimerNotify::expireStatus searchTimer::expire ( const epicsTime & currentTi
if ( this->iiu.channelCount () == 0 ) {
debugPrintf ( ( "all channels connected\n" ) );
epicsGuard < searchTimerMutex > locker ( this->mutex );
this->active = false;
this->noDelay = false;
return noRestart;
}
else if ( this->retry < maxSearchTries ) {
epicsGuard < searchTimerMutex > locker ( this->mutex );
this->noDelay = this->period == 0.0;
return expireStatus ( restart, this->period );
}
else {
debugPrintf ( ( "maximum search tries exceeded - giving up\n" ) );
epicsGuard < searchTimerMutex > locker ( this->mutex );
this->active = false;
this->noDelay = false;
return noRestart;