Spatializer: track scheduler statistics

This requires the spatializer to be enabled to run.

Test: adb shell dumpsys media.audio_flinger
Test: atest media_process_tests
Bug: 228648325
Change-Id: I2315064a548d5dced82a08c7f64c7fc2e900905b
diff --git a/media/utils/Process.cpp b/media/utils/Process.cpp
new file mode 100644
index 0000000..8fe8003
--- /dev/null
+++ b/media/utils/Process.cpp
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2022 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.
+ */
+
+#define LOG_TAG "Process"
+#include <utils/Log.h>
+#include <mediautils/Process.h>
+
+#include <android-base/file.h>
+#include <android-base/strings.h>
+#include <cstdlib>
+
+namespace {
+
+void processLine(std::string_view s, std::map<std::string, double>& m) {
+    if (s.empty()) return;
+
+    const size_t colon_pos = s.find(':');
+    if (colon_pos == std::string_view::npos) return;
+
+    const size_t space_pos = s.find(' ');
+    if (space_pos == 0 || space_pos == std::string_view::npos || space_pos > colon_pos) return;
+    std::string key(s.data(), s.data() + space_pos);
+
+    const size_t value_pos = s.find_first_not_of(' ', colon_pos + 1);
+    if (value_pos == std::string_view::npos) return;
+
+    const double value = strtod(s.data() + value_pos, nullptr /* end */);
+    m[std::move(key)] = value;
+}
+
+} // namespace
+
+namespace android::mediautils {
+
+std::string getThreadSchedAsString(pid_t tid) {
+    const pid_t pid = getpid();
+    const std::string path = std::string("/proc/").append(std::to_string(pid))
+            .append("/task/").append(std::to_string(tid)).append("/sched");
+    std::string sched;
+    (void)android::base::ReadFileToString(path.c_str(), &sched);
+    return sched;
+}
+
+std::map<std::string, double> parseThreadSchedString(const std::string& schedString) {
+    std::map<std::string, double> m;
+    if (schedString.empty()) return m;
+    std::vector<std::string> stringlist = android::base::Split(schedString, "\n");
+
+    //  OK we use values not strings... m["summary"] = stringlist[0];
+    for (size_t i = 2; i < stringlist.size(); ++i) {
+        processLine(stringlist[i], m);
+    }
+    return m;
+}
+
+} // namespace android::mediautils