| package com.android.internal.os; |
| |
| import android.os.StrictMode; |
| import android.text.TextUtils; |
| import android.util.LongSparseLongArray; |
| import android.util.Slog; |
| |
| import com.android.internal.annotations.VisibleForTesting; |
| |
| import java.io.BufferedReader; |
| import java.io.FileReader; |
| import java.io.IOException; |
| |
| /** |
| * Reads DDR time spent at various frequencies and stores the data. Supports diff comparison with |
| * other KernelMemoryBandwidthStats objects. The sysfs file has the format: |
| * |
| * freq time_in_bucket ... time_in_bucket |
| * ... |
| * freq time_in_bucket ... time_in_bucket |
| * |
| * where time is measured in nanoseconds. |
| */ |
| public class KernelMemoryBandwidthStats { |
| private static final String TAG = "KernelMemoryBandwidthStats"; |
| |
| final protected LongSparseLongArray mBandwidthEntries = new LongSparseLongArray(); |
| private static final String mSysfsFile = "/sys/kernel/memory_state_time/show_stat"; |
| private static final boolean DEBUG = false; |
| |
| public void updateStats() { |
| StrictMode.ThreadPolicy policy = StrictMode.allowThreadDiskReads(); |
| try (BufferedReader reader = new BufferedReader(new FileReader(mSysfsFile))) { |
| parseStats(reader); |
| } catch (IOException e) { |
| Slog.e(TAG, "Failed to read memory bandwidth: " + e.getMessage()); |
| mBandwidthEntries.clear(); |
| } finally { |
| StrictMode.setThreadPolicy(policy); |
| } |
| } |
| |
| @VisibleForTesting |
| public void parseStats(BufferedReader reader) throws IOException { |
| String line; |
| TextUtils.SimpleStringSplitter splitter = new TextUtils.SimpleStringSplitter(' '); |
| mBandwidthEntries.clear(); |
| while ((line = reader.readLine()) != null) { |
| splitter.setString(line); |
| splitter.next(); |
| int bandwidth = 0; |
| int index; |
| do { |
| if ((index = mBandwidthEntries.indexOfKey(bandwidth)) >= 0) { |
| mBandwidthEntries.put(bandwidth, mBandwidthEntries.valueAt(index) |
| + Long.parseLong(splitter.next()) / 1000000); |
| } else { |
| mBandwidthEntries.put(bandwidth, Long.parseLong(splitter.next()) / 1000000); |
| } |
| if (DEBUG) { |
| Slog.d(TAG, String.format("bandwidth: %s time: %s", bandwidth, |
| mBandwidthEntries.get(bandwidth))); |
| } |
| bandwidth++; |
| } while(splitter.hasNext()); |
| } |
| } |
| |
| public LongSparseLongArray getBandwidthEntries() { |
| return mBandwidthEntries; |
| } |
| } |