int devIocStatsInitCpuUsage(void)
{
int nBurnNoContention = 0;
double tToWait = SECONDS_TO_BURN;
epicsTimeStamp tStart, tEnd;
if (cpuUsage.startSem) return 0;
/* Initialize only if OS wants to spin */
if (tToWait > 0) {
/*wait for a tick*/
epicsTimeGetCurrent(&tStart);
do {
epicsTimeGetCurrent(&tEnd);
} while ( epicsTimeDiffInSeconds(&tEnd, &tStart) <= 0.0 );
epicsTimeGetCurrent(&tStart);
while(TRUE)
{
cpuBurn();
epicsTimeGetCurrent(&tEnd);
cpuUsage.tNow = epicsTimeDiffInSeconds(&tEnd, &tStart);
if (cpuUsage.tNow >= tToWait ) break;
nBurnNoContention++;
}
cpuUsage.nBurnNoContention = nBurnNoContention;
cpuUsage.nBurnNow = nBurnNoContention;
cpuUsage.startSem = epicsEventMustCreate(epicsEventFull);
cpuUsage.tNoContention = cpuUsage.tNow;
/*
* FIXME: epicsThreadPriorityMin is not really the lowest
* priority. We could use a native call to
* lower our priority further but OTOH there is not
* much going on at these low levels...
*/
epicsThreadCreate("cpuUsageTask",
epicsThreadPriorityMin,
epicsThreadGetStackSize(epicsThreadStackMedium),
(EPICSTHREADFUNC)cpuUsageTask,
0);
} else {
cpuUsage.startSem = 0;
}
return 0;
}
static void cpuUsageTask(void *parm)
{
while(TRUE)
{
int i;
epicsTimeStamp tStart, tEnd;
epicsEventWait(cpuUsage.startSem);
cpuUsage.nBurnNow=0;
epicsTimeGetCurrent(&tStart);
for(i=0; i< cpuUsage.nBurnNoContention; i++)
{
cpuBurn();
epicsTimeGetCurrent(&tEnd);
cpuUsage.tNow = epicsTimeDiffInSeconds(&tEnd, &tStart);
++cpuUsage.nBurnNow;
}
cpuUsage.didNotComplete = FALSE;
}
}
static void cpuUsageTask()
{
while(TRUE) {
int i;
unsigned long tickStart,tickEnd;
semTake(pcpuUsage->startSem,WAIT_FOREVER);
pcpuUsage->ticksNow=0;
pcpuUsage->nBurnNow=0;
tickStart = tickGet();
for(i=0; i< pcpuUsage->nBurnNoContention; i++) {
cpuBurn();
pcpuUsage->ticksNow = tickGet() - tickStart;
++pcpuUsage->nBurnNow;
}
tickEnd = tickGet();
pcpuUsage->didNotComplete = FALSE;
pcpuUsage->ticksNow = tickEnd - tickStart;
}
}
static void cpuUsageInit(void)
{
unsigned long tickStart,tickNow;
int nBurnNoContention=0;
int ticksToWait;
ticksToWait = SECONDS_TO_BURN*sysClkRateGet();
pcpuUsage = calloc(1,sizeof(cpuUsage));
tickStart = tickGet();
/*wait for a tick*/
while(tickStart==(tickNow = tickGet())) {;}
tickStart = tickNow;
while(TRUE) {
if((tickGet() - tickStart)>=ticksToWait) break;
cpuBurn();
nBurnNoContention++;
}
pcpuUsage->nBurnNoContention = nBurnNoContention;
pcpuUsage->startSem = semBCreate (SEM_Q_FIFO,SEM_FULL);
pcpuUsage->ticksNoContention = ticksToWait;
taskSpawn("cpuUsageTask",255,VX_FP_TASK,1000,(FUNCPTR)cpuUsageTask,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
}
