1 files changed, 73 insertions, 0 deletions
diff --git a/tools/profiler/core/ProfilerCPUFreq-linux-android.cpp b/tools/profiler/core/ProfilerCPUFreq-linux-android.cpp
new file mode 100644
index 0000000000..c7efbbd75f
--- /dev/null
+++ b/tools/profiler/core/ProfilerCPUFreq-linux-android.cpp
@@ -0,0 +1,73 @@
+/* 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;
+}