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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "ProfilerCPUFreq.h"
#include "nsThreadUtils.h"
#include <fcntl.h>
#include <unistd.h>
ProfilerCPUFreq::ProfilerCPUFreq() {
if (!mCPUCounters.resize(mozilla::GetNumberOfProcessors())) {
NS_WARNING("failing to resize the mCPUCounters vector");
return;
}
for (unsigned cpuId = 0; cpuId < mCPUCounters.length(); ++cpuId) {
const size_t buf_sz = 64;
char buf[buf_sz];
int rv = sprintf(
buf, "/sys/devices/system/cpu/cpu%u/cpufreq/scaling_cur_freq", cpuId);
if (NS_WARN_IF(rv < 0)) {
continue;
}
int fd = open(buf, O_RDONLY);
if (NS_WARN_IF(!fd)) {
continue;
}
mCPUCounters[cpuId].fd = fd;
}
}
ProfilerCPUFreq::~ProfilerCPUFreq() {
for (CPUCounterInfo& CPUCounter : mCPUCounters) {
int fd = CPUCounter.fd;
if (NS_WARN_IF(!fd)) {
continue;
}
close(fd);
CPUCounter.fd = 0;
}
}
uint32_t ProfilerCPUFreq::GetCPUSpeedMHz(unsigned cpuId) {
MOZ_ASSERT(cpuId < mCPUCounters.length());
int fd = mCPUCounters[cpuId].fd;
if (NS_WARN_IF(!fd)) {
return 0;
}
long rv = lseek(fd, 0, SEEK_SET);
if (NS_WARN_IF(rv < 0)) {
return 0;
}
const size_t buf_sz = 64;
char buf[buf_sz];
rv = read(fd, buf, buf_sz);
if (NS_WARN_IF(rv < 0)) {
return 0;
}
int cpufreq = 0;
rv = sscanf(buf, "%u", &cpufreq);
if (NS_WARN_IF(rv != 1)) {
return 0;
}
// Convert kHz to MHz, rounding to the nearst 10Mhz, to ignore tiny
// variations that are likely due to rounding errors.
return uint32_t(cpufreq / 10000) * 10;
}
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