Test for a fixed duration rather than fixed amount of traffic.

app/src/main/java/org/briarproject/interferometer/MainViewModel.java

@@ -59,7 +59,7 @@ public class MainViewModel extends AndroidViewModel {
 
 	private static final int BUFFER_SIZE = 4096;
 	private static final int MS_PER_UPDATE = 250;
-	private static final int BYTES_TO_TRANSFER = 10_000_000;
+	private static final int MS_PER_TRANSFER = 5_000;
 	private static final int TRANSFERS_PER_CONDITION = 10;
 
 	private static final String TAG = "Interferometer";
@@ -121,7 +121,7 @@ public class MainViewModel extends AndroidViewModel {
 				Future<?> discoveryTask = startDiscovery(adapter);
 				try {
 					testPhase.postValue(DISCOVERY);
-					Log.i(TAG, "Testing throughput with Bluetooth enabled");
+					Log.i(TAG, "Testing throughput with Bluetooth discovery");
 					List<Long> downloadDiscovery = new ArrayList<>();
 					List<Long> uploadDiscovery = new ArrayList<>();
 					if (!testThroughput(hostPort, downloadDiscovery, uploadDiscovery)) return;
@@ -265,24 +265,26 @@ public class MainViewModel extends AndroidViewModel {
 			Log.i(TAG, "Connected, requesting upload");
 			OutputStream out = s.getOutputStream();
 			out.write(CONNECTION_TYPE_UPLOAD);
+			out.flush();
 
 			byte[] buf = new byte[BUFFER_SIZE];
 			new Random().nextBytes(buf);
 			long start = System.nanoTime();
+			long now = start;
+			long end = start + MS_PER_TRANSFER * 1_000_000L;
 			long lastUpdate = 0;
 			int bytesSinceLastUpdate = 0;
 			int bytesTotal = 0;
 
-			while (bytesTotal < BYTES_TO_TRANSFER) {
-				int len = Math.min(BUFFER_SIZE, BYTES_TO_TRANSFER - bytesTotal);
-				out.write(buf, 0, len);
+			while (now < end) {
+				out.write(buf);
 				if (Thread.currentThread().isInterrupted()) {
 					Log.i(TAG, "Upload to " + hostPort + " interrupted");
 					return -1;
 				}
-				bytesSinceLastUpdate += len;
-				bytesTotal += len;
-				long now = System.nanoTime();
+				bytesSinceLastUpdate += BUFFER_SIZE;
+				bytesTotal += BUFFER_SIZE;
+				now = System.nanoTime();
 				long msSinceLastUpdate = (now - lastUpdate) / 1_000_000;
 				if (msSinceLastUpdate >= MS_PER_UPDATE) {
 					long bytesPerSecond = bytesSinceLastUpdate * 1000L / msSinceLastUpdate;
@@ -292,7 +294,6 @@ public class MainViewModel extends AndroidViewModel {
 				}
 			}
 			Log.i(TAG, "Upload to " + hostPort + " finished");
-			long now = System.nanoTime();
 			long msSinceStart = (now - start) / 1_000_000;
 			return bytesTotal * 1000L / msSinceStart;
 		} catch (IOException e) {
@@ -315,17 +316,19 @@ public class MainViewModel extends AndroidViewModel {
 			Log.i(TAG, "Connected, requesting download");
 			OutputStream out = s.getOutputStream();
 			out.write(CONNECTION_TYPE_DOWNLOAD);
+			out.flush();
 
 			InputStream in = s.getInputStream();
 			byte[] buf = new byte[BUFFER_SIZE];
 			long start = System.nanoTime();
+			long now = start;
+			long end = start + MS_PER_TRANSFER * 1_000_000L;
 			long lastUpdate = 0;
 			int bytesSinceLastUpdate = 0;
 			int bytesTotal = 0;
 
-			while (bytesTotal < BYTES_TO_TRANSFER) {
-				int len = Math.min(BUFFER_SIZE, BYTES_TO_TRANSFER - bytesTotal);
-				int read = in.read(buf, 0, len);
+			while (now < end) {
+				int read = in.read(buf);
 				if (read == -1) {
 					Log.w(TAG, "Download from " + hostPort + " finished early");
 					return -1;
@@ -336,7 +339,7 @@ public class MainViewModel extends AndroidViewModel {
 				}
 				bytesSinceLastUpdate += read;
 				bytesTotal += read;
-				long now = System.nanoTime();
+				now = System.nanoTime();
 				long msSinceLastUpdate = (now - lastUpdate) / 1_000_000;
 				if (msSinceLastUpdate >= MS_PER_UPDATE) {
 					long bytesPerSecond = bytesSinceLastUpdate * 1000L / msSinceLastUpdate;
@@ -346,7 +349,7 @@ public class MainViewModel extends AndroidViewModel {
 				}
 			}
 			Log.i(TAG, "Download from " + hostPort + " finished");
-			long now = System.nanoTime();
+			now = System.nanoTime();
 			long msSinceStart = (now - start) / 1_000_000;
 			return bytesTotal * 1000L / msSinceStart;
 		} catch (IOException e) {