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/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "ThermalManager.h"
#include "SkOSFile.h"
#include <stdio.h>
#ifndef SK_BUILD_FOR_WIN32
#include <unistd.h>
#endif
#ifdef THERMAL_MANAGER_SUPPORTED
/*
* ThermalManager is completely dependent on sysfs to monitor thermal temperatures. In sysfs
* thermal management is controlled by a number of thermal zones. They are laid out as follows:
* /sys/class/thermal/thermal_zoneN where N is the number of the thermal zone starting at 0.
*
* Inside each thermal_zone folder is a file called 'temp,' which has the current temperature
* reading from the sensor in that zone, as well as 0 or more files called 'trip_point_N_temp.'
*
* When the reading in temp is greater than one of the numbers in the trip_point files, then the
* kernel will take some kind of action. This is all documented online.
*
* In any case, the goal of this class is to sleep right before a trip point is about to be
* triggered, thus naturally cooling the system and preventing thermal throttling.
*/
ThermalManager::ThermalManager(int32_t threshold, uint32_t sleepIntervalMs, uint32_t timeoutMs)
: fSleepIntervalMs(sleepIntervalMs)
, fTimeoutMs(timeoutMs) {
static const char* kThermalZonePath = "/sys/class/thermal/";
SkOSFile::Iter it(kThermalZonePath);
SkString path;
while (it.next(&path, true)) {
if (!path.contains("thermal_zone")) {
continue;
}
SkString fullPath(kThermalZonePath);
fullPath.append(path);
SkOSFile::Iter thermalZoneIt(fullPath.c_str());
SkString filename;
while (thermalZoneIt.next(&filename)) {
if (!(filename.contains("trip_point") && filename.contains("temp"))) {
continue;
}
fTripPoints.push_back(TripPoint(fullPath, filename, threshold));
}
}
}
bool ThermalManager::coolOffIfNecessary() {
uint32_t i = 0, totalTimeSleptMs = 0;
while (i < (uint32_t)fTripPoints.count() && totalTimeSleptMs < fTimeoutMs) {
if (fTripPoints[i].willTrip()) {
sleep(fSleepIntervalMs);
totalTimeSleptMs += fSleepIntervalMs;
} else {
i++;
}
}
return totalTimeSleptMs < fTimeoutMs;
}
int32_t ThermalManager::OpenFileAndReadInt32(const char* path) {
FILE* tempFile = fopen(path, "r");
SkASSERT(tempFile);
int32_t value;
int ret = fscanf(tempFile, "%d", &value);
if (!ret) {
SkDebugf("Could not read temperature\n");
SkASSERT(false);
}
fclose(tempFile);
return value;
}
ThermalManager::TripPoint::TripPoint(SkString thermalZoneRoot, SkString pointName,
int32_t threshold)
: fThermalZoneRoot(thermalZoneRoot)
, fPointName(pointName) {
SkString fullPath(thermalZoneRoot);
fullPath.appendf("/%s", pointName.c_str());
fPoint = OpenFileAndReadInt32(fullPath.c_str());
fBase = GetTemp(fThermalZoneRoot);
fThreshold = threshold;
fDisabled = fBase + fThreshold >= fPoint; // We disable any trip point which start off
// triggered
}
bool ThermalManager::TripPoint::willTrip() {
int32_t currentTemp = GetTemp(fThermalZoneRoot);
bool wouldTrip = !fDisabled && currentTemp + fThreshold >= fPoint;
if (wouldTrip) {
SkDebugf("%s/%s would trip {%d,%d,%d,%d}\n", fThermalZoneRoot.c_str(),
fPointName.c_str(), fBase, currentTemp, fPoint, fThreshold);
}
return wouldTrip;
}
#endif
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