Files
pcas/src/cas/generic/beaconAnomalyGovernor.cc
T
2002-09-20 17:33:10 +00:00

84 lines
2.6 KiB
C++

/*************************************************************************\
* Copyright (c) 2002 The University of Chicago, as Operator of Argonne
* National Laboratory.
* Copyright (c) 2002 The Regents of the University of California, as
* Operator of Los Alamos National Laboratory.
* EPICS BASE Versions 3.13.7
* and higher are distributed subject to a Software License Agreement found
* in file LICENSE that is included with this distribution.
\*************************************************************************/
/*
* $Id$
*
* Author Jeffrey O. Hill
* johill@lanl.gov
* 505 665 1831
*/
#include "beaconAnomalyGovernor.h"
#include "beaconTimer.h"
#include "server.h"
//
// the minimum period between beacon anomalies
// -------------------------------------------
//
// o Gateways imply a tradeoff towards less traffic while
// paying a price of a less tightly coupled environment.
// Therefore, clients should not expect instant reconnects
// when a server is rebooted on the other side of a gateway.
//
// o In a quiescent system servers should not need to be
// rebooted and network connectivity should be constant.
//
// o Clients will keep trying to reach channels for around
// 15 min after the last beacon anomaly was seen.
//
// o The exponential backoff mechanism in the beacon timer
// ensures that clients will detect beacon anomalies
// continuously for around 30 seconds after each beacon
// anomaly is requested.
//
static const double CAServerMinBeaconAnomalyPeriod = 60.0 * 5.0; // seconds
beaconAnomalyGovernor::beaconAnomalyGovernor ( caServerI & casIn ) :
timer ( fileDescriptorManager.createTimer () ), cas ( casIn ),
anomalyPending ( false )
{
}
beaconAnomalyGovernor::~beaconAnomalyGovernor()
{
}
void beaconAnomalyGovernor::start ()
{
// order of operations here impacts thread safety
this->anomalyPending = true;
epicsTimer::expireInfo expInfo = this->timer.getExpireInfo ();
if ( ! expInfo.active ) {
this->cas.beaconTmr.generateBeaconAnomaly ();
this->timer.start ( *this, CAServerMinBeaconAnomalyPeriod );
this->anomalyPending = false;
}
}
epicsTimerNotify::expireStatus beaconAnomalyGovernor::expire ( const epicsTime & )
{
if ( this->anomalyPending ) {
this->anomalyPending = false;
this->cas.beaconTmr.generateBeaconAnomaly ();
}
return noRestart;
}
void beaconAnomalyGovernor::show ( unsigned level ) const
{
printf ( "beaconAnomalyGovernor: anomalyPending = %s\n",
this->anomalyPending ? "T": "F" );
if ( level ) {
this->timer.show ( level - 1 );
}
}