* Copyright 2013 Paweł Dziepak, pdziepak@quarnos.org.
* Distributed under the terms of the MIT License.
*/
#ifndef _KERNEL_LOAD_TRACKING_H
#define _KERNEL_LOAD_TRACKING_H
#include <OS.h>
const int32 kMaxLoad = 1000;
const bigtime_t kLoadMeasureInterval = 1000;
const bigtime_t kIntervalInaccuracy = kLoadMeasureInterval / 4;
static inline int32
compute_load(bigtime_t& measureTime, bigtime_t& measureActiveTime, int32& load,
bigtime_t now)
{
if (measureTime == 0) {
measureTime = now;
return -1;
}
bigtime_t deltaTime = now - measureTime;
if (deltaTime < kLoadMeasureInterval)
return -1;
int32 oldLoad = load;
ASSERT(oldLoad >= 0 && oldLoad <= kMaxLoad);
int32 newLoad = measureActiveTime * kMaxLoad;
newLoad /= max_c(deltaTime, 1);
newLoad = max_c(min_c(newLoad, kMaxLoad), 0);
measureActiveTime = 0;
measureTime = now;
deltaTime += kIntervalInaccuracy;
bigtime_t n = deltaTime / kLoadMeasureInterval;
ASSERT(n > 0);
if (n > 10)
load = newLoad;
else {
newLoad *= (1 << n) - 1;
load = (load + newLoad) / (1 << n);
ASSERT(load >= 0 && load <= kMaxLoad);
}
return oldLoad;
}
#endif
