1 files changed, 113 insertions, 0 deletions
diff --git a/perfprofd/cpuconfig.cc b/perfprofd/cpuconfig.cc
new file mode 100644
index 00000000..0f23fd0f
--- /dev/null
+++ b/perfprofd/cpuconfig.cc
@@ -0,0 +1,113 @@
+/*
+**
+** Copyright 2015, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License");
+** you may not use this file except in compliance with the License.
+** You may obtain a copy of the License at
+**
+**     http://www.apache.org/licenses/LICENSE-2.0
+**
+** Unless required by applicable law or agreed to in writing, software
+** distributed under the License is distributed on an "AS IS" BASIS,
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+** See the License for the specific language governing permissions and
+** limitations under the License.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <string>
+#include <sstream>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include <android-base/logging.h>
+#ifdef __BIONIC__
+#include <android-base/properties.h>
+#endif
+
+#include "cpuconfig.h"
+
+#define SYSFSCPU "/sys/devices/system/cpu"
+
+HardwireCpuHelper::HardwireCpuHelper(bool perform)
+    : mpdecision_stopped_(false)
+{
+  if (perform && GetMpdecisionRunning()) {
+    mpdecision_stopped_ = true;
+    StopMpdecision();
+    int ncores = GetNumCores();
+    for (int i = 0; i < ncores; ++i) {
+      OnlineCore(i, 1);
+    }
+  }
+}
+
+HardwireCpuHelper::~HardwireCpuHelper()
+{
+  if (mpdecision_stopped_) {
+    RestartMpdecision();
+  }
+}
+
+bool HardwireCpuHelper::GetMpdecisionRunning()
+{
+#ifdef __BIONIC__
+  return android::base::GetProperty("init.svc.mpdecision", "") == "running";
+#else
+  return false;
+#endif
+}
+
+
+int HardwireCpuHelper::GetNumCores()
+{
+  int ncores = -1;
+  std::string possible(SYSFSCPU "/possible");
+  FILE *fp = fopen(possible.c_str(), "re");
+  if (fp) {
+    unsigned lo = 0, hi = 0;
+    if (fscanf(fp, "%u-%u", &lo, &hi) == 2) {
+      ncores = hi - lo + 1;
+    }
+    fclose(fp);
+  }
+  return ncores;
+}
+
+void HardwireCpuHelper::OnlineCore(int i, int onoff)
+{
+  std::stringstream ss;
+  ss << SYSFSCPU "/cpu" << i << "/online";
+  FILE *fp = fopen(ss.str().c_str(), "we");
+  if (fp) {
+    fprintf(fp, onoff ? "1\n" : "0\n");
+    fclose(fp);
+  } else {
+    PLOG(WARNING) << "open failed for " << ss.str();
+  }
+}
+
+void HardwireCpuHelper::StopMpdecision()
+{
+#ifdef __BIONIC__
+  if (!android::base::SetProperty("ctl.stop", "mpdecision")) {
+    LOG(ERROR) << "setprop ctl.stop mpdecision failed";
+  }
+#endif
+}
+
+void HardwireCpuHelper::RestartMpdecision()
+{
+#ifdef __BIONIC__
+  // Don't try to offline the cores we previously onlined -- let
+  // mpdecision figure out what to do
+
+  if (!android::base::SetProperty("ctl.start", "mpdecision")) {
+    LOG(ERROR) << "setprop ctl.start mpdecision failed";
+  }
+#endif
+}