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setReadQueue(...), enabled by default in SerialInputOutputManager

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for applications doing permanent read() with timeout=0, multiple buffers can be used to copy next data from Linux kernel, while the current data is processed.
This commit is contained in:
Kai Morich 2025-02-16 09:34:39 +01:00
parent 026355f61e
commit 90246e5c7b
7 changed files with 312 additions and 23 deletions
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68
usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/DeviceTest.java
View File

@ -14,6 +14,7 @@ import android.content.Context;
import android.hardware.usb.UsbDevice;
import android.hardware.usb.UsbDeviceConnection;
import android.hardware.usb.UsbManager;
import android.hardware.usb.UsbRequest;
import android.os.Process;
import androidx.test.core.app.ApplicationProvider;
import androidx.test.platform.app.InstrumentationRegistry;
@ -43,7 +44,6 @@ import com.hoho.android.usbserial.driver.UsbSerialPort.ControlLine;
import com.hoho.android.usbserial.driver.UsbSerialPort.FlowControl;
import com.hoho.android.usbserial.util.XonXoffFilter;
import org.junit.After;
import org.junit.AfterClass;
import org.junit.Assume;
@ -60,11 +60,13 @@ import java.io.IOException;
import java.nio.BufferOverflowException;
import java.util.Arrays;
import java.util.EnumSet;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;
import static org.hamcrest.CoreMatchers.anyOf;
import static org.hamcrest.MatcherAssert.assertThat;
@ -1148,7 +1150,7 @@ public class DeviceTest {
public void readBufferOverflow() throws Exception {
if(usb.serialDriver instanceof CdcAcmSerialDriver)
telnet.writeDelay = 10; // arduino_leonardo_bridge.ino sends each byte in own USB packet, which is horribly slow
usb.open();
usb.open(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_IOMANAGER_READQUEUE));
usb.setParameters(115200, 8, 1, UsbSerialPort.PARITY_NONE);
telnet.setParameters(115200, 8, 1, UsbSerialPort.PARITY_NONE);
@ -1198,6 +1200,64 @@ public class DeviceTest {
assertTrue(data.length() != expected.length());
}
@Test
public void readQueue() throws Exception {
class CountingUsbRequest extends UsbRequest {
int count;
@Override public Object getClientData() { count += 1; return super.getClientData(); }
}
usb.open(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_IOMANAGER_THREAD));
int len = usb.serialPort.getReadEndpoint().getMaxPacketSize();
usb.close();
CommonUsbSerialPortWrapper.setReadQueueRequestSupplier(usb.serialPort, CountingUsbRequest::new);
CommonUsbSerialPort port = (CommonUsbSerialPort) usb.serialPort;
port.setReadQueue(2, len);
usb.open(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_IOMANAGER_START));
usb.setParameters(115200, 8, 1, UsbSerialPort.PARITY_NONE);
telnet.setParameters(115200, 8, 1, UsbSerialPort.PARITY_NONE);
assertEquals(2, port.getReadQueueBufferCount());
assertEquals(4, usb.ioManager.getReadQueueBufferCount()); // not set at port yet
assertThrows(IllegalStateException.class, () -> usb.ioManager.setReadQueue(1)); // cannot reduce bufferCount
usb.ioManager.setReadQueue(2);
usb.ioManager.start();
port.setReadQueue(4, len);
// linux kernel does round-robin
LinkedList<UsbRequest> requests = CommonUsbSerialPortWrapper.getReadQueueRequests(usb.serialPort);
assertNotNull(requests);
for (int i=0; i<16; i++) {
telnet.write(new byte[1]);
usb.read(1);
}
List<Integer> requestCounts;
if(usb.serialDriver instanceof FtdiSerialDriver) {
for (UsbRequest request : requests) {
int count = ((CountingUsbRequest)request).count;
assertTrue(String.valueOf(count), count >= 4);
}
} else {
requestCounts = requests.stream().map(r -> ((CountingUsbRequest)r).count).collect(Collectors.toList());
assertThat(requestCounts, equalTo(Arrays.asList(4, 4, 4, 4)));
}
usb.ioManager.setReadQueue(6);
for (int i=0; i<18; i++) {
telnet.write(new byte[1]);
usb.read(1);
}
requestCounts = requests.stream().map(r -> ((CountingUsbRequest)r).count).collect(Collectors.toList());
if(!(usb.serialDriver instanceof FtdiSerialDriver)) {
assertThat(requestCounts, equalTo(Arrays.asList(7, 7, 7, 7, 3, 3)));
}
usb.close();
usb.open(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_IOMANAGER_START));
port.setReadQueue(8, len);
assertThrows(IllegalStateException.class, () -> usb.serialPort.read(new byte[len], 1) ); // cannot use timeout != 0
assertThrows(IllegalStateException.class, () -> usb.serialPort.read(new byte[4], 0) ); // cannot use different length
assertThrows(IllegalStateException.class, () -> usb.ioManager.start()); // cannot reduce bufferCount
}
@Test
public void readSpeed() throws Exception {
// see logcat for performance results
@ -1223,7 +1283,7 @@ public class DeviceTest {
if(usb.serialDriver instanceof CdcAcmSerialDriver)
writeAhead = 50;
usb.open(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_IOMANAGER_START));
usb.open(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_IOMANAGER_START, UsbWrapper.OpenCloseFlags.NO_IOMANAGER_READQUEUE));
usb.ioManager.setReadTimeout(readTimeout);
if(readBufferSize > 0)
usb.ioManager.setReadBufferSize(readBufferSize);
@ -1421,7 +1481,7 @@ public class DeviceTest {
usb.ioManager.setWriteTimeout(usb.ioManager.getWriteTimeout());
usb.close();
usb.open(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_IOMANAGER_START)); // creates new IoManager
usb.open(EnumSet.of(UsbWrapper.OpenCloseFlags.NO_IOMANAGER_START, UsbWrapper.OpenCloseFlags.NO_IOMANAGER_READQUEUE)); // creates new IoManager
usb.setParameters(19200, 8, 1, UsbSerialPort.PARITY_NONE);
telnet.setParameters(19200, 8, 1, UsbSerialPort.PARITY_NONE);
usb.ioManager.setThreadPriority(Process.THREAD_PRIORITY_DEFAULT);

16
usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/driver/CommonUsbSerialPortWrapper.java
View File

@ -1,8 +1,24 @@
package com.hoho.android.usbserial.driver;
import android.hardware.usb.UsbRequest;
import com.hoho.android.usbserial.util.UsbUtils;
import java.util.LinkedList;
public class CommonUsbSerialPortWrapper {
public static byte[] getWriteBuffer(UsbSerialPort serialPort) {
CommonUsbSerialPort commonSerialPort = (CommonUsbSerialPort) serialPort;
return commonSerialPort.mWriteBuffer;
}
public static LinkedList<UsbRequest> getReadQueueRequests(UsbSerialPort serialPort) {
CommonUsbSerialPort commonSerialPort = (CommonUsbSerialPort) serialPort;
return commonSerialPort.mReadQueueRequests;
}
public static void setReadQueueRequestSupplier(UsbSerialPort serialPort, UsbUtils.Supplier<UsbRequest> supplier) {
CommonUsbSerialPort commonSerialPort = (CommonUsbSerialPort) serialPort;
commonSerialPort.mUsbRequestSupplier = supplier;
}
}

6
usbSerialForAndroid/src/androidTest/java/com/hoho/android/usbserial/util/UsbWrapper.java
View File

@ -41,7 +41,7 @@ public class UsbWrapper implements SerialInputOutputManager.Listener {
public final static int USB_WRITE_WAIT = 500;
private static final String TAG = UsbWrapper.class.getSimpleName();
public enum OpenCloseFlags { NO_IOMANAGER_THREAD, NO_IOMANAGER_START, NO_CONTROL_LINE_INIT, NO_DEVICE_CONNECTION };
public enum OpenCloseFlags { NO_IOMANAGER_THREAD, NO_IOMANAGER_READQUEUE, NO_IOMANAGER_START, NO_CONTROL_LINE_INIT, NO_DEVICE_CONNECTION };
// constructor
final Context context;
@ -198,7 +198,7 @@ public class UsbWrapper implements SerialInputOutputManager.Listener {
serialPort.close();
} catch (Exception ignored) {
}
//usbSerialPort = null;
((CommonUsbSerialPort)serialPort).setReadQueue(0, 0);
}
if(!flags.contains(OpenCloseFlags.NO_DEVICE_CONNECTION)) {
deviceConnection = null; // closed in usbSerialPort.close()
@ -233,6 +233,8 @@ public class UsbWrapper implements SerialInputOutputManager.Listener {
}
if(!flags.contains(OpenCloseFlags.NO_IOMANAGER_THREAD)) {
ioManager = new SerialInputOutputManager(serialPort, this);
if(flags.contains(OpenCloseFlags.NO_IOMANAGER_READQUEUE))
ioManager.setReadQueue(0);
if(!flags.contains(OpenCloseFlags.NO_IOMANAGER_START))
ioManager.start();
}

103
usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/driver/CommonUsbSerialPort.java
View File

@ -14,10 +14,13 @@ import android.os.Build;
import android.util.Log;
import com.hoho.android.usbserial.util.MonotonicClock;
import com.hoho.android.usbserial.util.UsbUtils;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.EnumSet;
import java.util.LinkedList;
import java.util.Objects;
/**
* A base class shared by several driver implementations.
@ -38,8 +41,12 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
protected UsbDeviceConnection mConnection;
protected UsbEndpoint mReadEndpoint;
protected UsbEndpoint mWriteEndpoint;
protected UsbRequest mUsbRequest;
protected UsbRequest mReadRequest;
protected LinkedList<UsbRequest> mReadQueueRequests;
private int mReadQueueBufferCount;
private int mReadQueueBufferSize;
protected FlowControl mFlowControl = FlowControl.NONE;
protected UsbUtils.Supplier<UsbRequest> mUsbRequestSupplier = UsbRequest::new; // override for testing
/**
* Internal write buffer.
@ -110,6 +117,50 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
}
}
/**
* for applications doing permanent read() with timeout=0, multiple buffers can be
* used to copy next data from Linux kernel, while the current data is processed.
* @param bufferCount number of buffers to use for readQueue
* disabled with 0
* @param bufferSize size of each buffer
*/
public void setReadQueue(int bufferCount, int bufferSize) {
if (bufferCount < 0) {
throw new IllegalArgumentException("Invalid bufferCount");
}
if (bufferCount > 0 && bufferSize <= 0) {
throw new IllegalArgumentException("Invalid bufferSize");
}
if(isOpen()) {
if (bufferCount < mReadQueueBufferCount) {
throw new IllegalStateException("Cannot reduce bufferCount when port is open");
}
if (mReadQueueBufferCount != 0 && bufferSize != mReadQueueBufferSize) {
throw new IllegalStateException("Cannot change bufferSize when port is open");
}
if (bufferCount > 0) {
if (mReadQueueRequests == null) {
mReadQueueRequests = new LinkedList<>();
}
for (int i = mReadQueueRequests.size(); i < bufferCount; i++) {
ByteBuffer buffer = ByteBuffer.allocate(bufferSize);
UsbRequest request = mUsbRequestSupplier.get();
request.initialize(mConnection, mReadEndpoint);
request.setClientData(buffer);
request.queue(buffer, bufferSize);
mReadQueueRequests.add(request);
}
}
}
mReadQueueBufferCount = bufferCount;
mReadQueueBufferSize = bufferSize;
}
public int getReadQueueBufferCount() { return mReadQueueBufferCount; }
public int getReadQueueBufferSize() { return mReadQueueBufferSize; }
private boolean useReadQueue() { return mReadQueueBufferCount != 0; }
@Override
public void open(UsbDeviceConnection connection) throws IOException {
if (mConnection != null) {
@ -125,8 +176,9 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
if (mReadEndpoint == null || mWriteEndpoint == null) {
throw new IOException("Could not get read & write endpoints");
}
mUsbRequest = new UsbRequest();
mUsbRequest.initialize(mConnection, mReadEndpoint);
mReadRequest = mUsbRequestSupplier.get();
mReadRequest.initialize(mConnection, mReadEndpoint);
setReadQueue(mReadQueueBufferCount, mReadQueueBufferSize); // fill mReadQueueRequests
ok = true;
} finally {
if (!ok) {
@ -144,11 +196,19 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
if (mConnection == null) {
throw new IOException("Already closed");
}
UsbRequest usbRequest = mUsbRequest;
mUsbRequest = null;
UsbRequest readRequest = mReadRequest;
mReadRequest = null;
try {
usbRequest.cancel();
readRequest.cancel();
} catch(Exception ignored) {}
if(mReadQueueRequests != null) {
for(UsbRequest readQueueRequest : mReadQueueRequests) {
try {
readQueueRequest.cancel();
} catch(Exception ignored) {}
}
mReadQueueRequests = null;
}
try {
closeInt();
} catch(Exception ignored) {}
@ -168,7 +228,7 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
}
protected void testConnection(boolean full, String msg) throws IOException {
if(mUsbRequest == null) {
if(mReadRequest == null) {
throw new IOException("Connection closed");
}
if(!full) {
@ -199,6 +259,9 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
length = Math.min(length, dest.length);
final int nread;
if (timeout != 0) {
if(useReadQueue()) {
throw new IllegalStateException("Cannot use timeout!=0 if readQueue is enabled");
}
// bulkTransfer will cause data loss with short timeout + high baud rates + continuous transfer
// https://stackoverflow.com/questions/9108548/android-usb-host-bulktransfer-is-losing-data
// but mConnection.requestWait(timeout) available since Android 8.0 es even worse,
@ -216,15 +279,31 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
testConnection(MonotonicClock.millis() < endTime);
} else {
final ByteBuffer buf = ByteBuffer.wrap(dest, 0, length);
if (!mUsbRequest.queue(buf, length)) {
throw new IOException("Queueing USB request failed");
ByteBuffer buf = null;
if(useReadQueue()) {
if (length != mReadQueueBufferSize) {
throw new IllegalStateException("Cannot use different length if readQueue is enabled");
}
} else {
buf = ByteBuffer.wrap(dest, 0, length);
if (!mReadRequest.queue(buf, length)) {
throw new IOException("Queueing USB request failed");
}
}
final UsbRequest response = mConnection.requestWait();
if (response == null) {
throw new IOException("Waiting for USB request failed");
}
nread = buf.position();
if(useReadQueue()) {
buf = (ByteBuffer) response.getClientData();
System.arraycopy(buf.array(), 0, dest, 0, buf.position());
if(mReadRequest != null) { // re-queue if connection not closed
if (!response.queue(buf, buf.capacity())) {
throw new IOException("Queueing USB request failed");
}
}
}
nread = Objects.requireNonNull(buf).position();
// Android error propagation is improvable:
// response != null & nread == 0 can be: connection lost, buffer to small, ???
if(nread == 0) {
@ -297,7 +376,7 @@ public abstract class CommonUsbSerialPort implements UsbSerialPort {
@Override
public boolean isOpen() {
return mUsbRequest != null;
return mReadRequest != null;
}
@Override

31
usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/util/SerialInputOutputManager.java
View File

@ -9,6 +9,7 @@ package com.hoho.android.usbserial.util;
import android.os.Process;
import android.util.Log;
import com.hoho.android.usbserial.driver.CommonUsbSerialPort;
import com.hoho.android.usbserial.driver.UsbSerialPort;
import java.io.IOException;
@ -33,16 +34,18 @@ public class SerialInputOutputManager {
public static boolean DEBUG = false;
private static final String TAG = SerialInputOutputManager.class.getSimpleName();
private static final int BUFSIZ = 4096;
private static final int WRITE_BUFFER_SIZE = 4096;
private static final int READ_QUEUE_BUFFER_COUNT = 4;
private int mReadTimeout = 0;
private int mWriteTimeout = 0;
private int mReadQueueBufferCount; // = READ_QUEUE_BUFFER_COUNT
private final Object mReadBufferLock = new Object();
private final Object mWriteBufferLock = new Object();
private ByteBuffer mReadBuffer; // default size = getReadEndpoint().getMaxPacketSize()
private ByteBuffer mWriteBuffer = ByteBuffer.allocate(BUFSIZ);
private ByteBuffer mWriteBuffer = ByteBuffer.allocate(WRITE_BUFFER_SIZE);
private int mThreadPriority = Process.THREAD_PRIORITY_URGENT_AUDIO;
private final AtomicReference<State> mState = new AtomicReference<>(State.STOPPED);
@ -65,12 +68,13 @@ public class SerialInputOutputManager {
public SerialInputOutputManager(UsbSerialPort serialPort) {
mSerialPort = serialPort;
mReadBuffer = ByteBuffer.allocate(serialPort.getReadEndpoint().getMaxPacketSize());
mReadQueueBufferCount = serialPort instanceof CommonUsbSerialPort ? READ_QUEUE_BUFFER_COUNT : 0;
//readQueueBufferSize fixed to getMaxPacketSize()
}
public SerialInputOutputManager(UsbSerialPort serialPort, Listener listener) {
mSerialPort = serialPort;
this(serialPort);
mListener = listener;
mReadBuffer = ByteBuffer.allocate(serialPort.getReadEndpoint().getMaxPacketSize());
}
public synchronized void setListener(Listener listener) {
@ -145,6 +149,22 @@ public class SerialInputOutputManager {
return mWriteBuffer.capacity();
}
/**
* Set read queue. Set buffer size before.
* @param bufferCount number of buffers to use for readQueue
* disable with value 0,
* default enabled as value 4 (READ_QUEUE_BUFFER_COUNT)
*/
public void setReadQueue(int bufferCount) {
if (!(mSerialPort instanceof CommonUsbSerialPort)) {
throw new IllegalArgumentException("only for CommonUsbSerialPort based drivers");
}
mReadQueueBufferCount = bufferCount;
((CommonUsbSerialPort) mSerialPort).setReadQueue(getReadQueueBufferCount(), getReadBufferSize());
}
public int getReadQueueBufferCount() { return mReadQueueBufferCount; }
/**
* write data asynchronously
*/
@ -159,6 +179,9 @@ public class SerialInputOutputManager {
* start SerialInputOutputManager in separate threads
*/
public void start() {
if(mSerialPort instanceof CommonUsbSerialPort) {
((CommonUsbSerialPort) mSerialPort).setReadQueue(mReadQueueBufferCount, getReadBufferSize());
}
if(mState.compareAndSet(State.STOPPED, State.STARTING)) {
mStartuplatch = new CountDownLatch(2);
new Thread(this::runRead, this.getClass().getSimpleName() + "_read").start();

6
usbSerialForAndroid/src/main/java/com/hoho/android/usbserial/util/UsbUtils.java
View File

@ -6,6 +6,11 @@ import java.util.ArrayList;
public class UsbUtils {
// copied from java.util.function.Supplier which is not available < API 24
public interface Supplier<T> {
T get();
}
private UsbUtils() {
}
@ -29,5 +34,4 @@ public class UsbUtils {
return descriptors;
}
}

105
usbSerialForAndroid/src/test/java/com/hoho/android/usbserial/driver/CommonUsbSerialPortTest.java Normal file
View File

@ -0,0 +1,105 @@
package com.hoho.android.usbserial.driver;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertThrows;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;
import android.hardware.usb.UsbDevice;
import android.hardware.usb.UsbDeviceConnection;
import android.hardware.usb.UsbEndpoint;
import android.hardware.usb.UsbRequest;
import org.junit.Test;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;
public class CommonUsbSerialPortTest {
static class DummySerialDriver implements UsbSerialDriver {
ArrayList<UsbSerialPort> ports = new ArrayList<>();
DummySerialDriver() { ports.add(new DummySerialPort(null, 0)); }
@Override
public UsbDevice getDevice() { return null; }
@Override
public List<UsbSerialPort> getPorts() { return ports; }
}
static class DummySerialPort extends CommonUsbSerialPort {
public DummySerialPort(UsbDevice device, int portNumber) {
super(device, portNumber);
mUsbRequestSupplier = DummyUsbRequest::new;
}
@Override
protected void openInt() throws IOException { mReadEndpoint = mWriteEndpoint = mock(UsbEndpoint.class); }
@Override
protected void closeInt() { }
@Override
public UsbSerialDriver getDriver() { return null; }
@Override
public void setParameters(int baudRate, int dataBits, int stopBits, int parity) throws IOException { }
}
static class DummyUsbRequest extends UsbRequest {
@Override
public boolean initialize(UsbDeviceConnection connection, UsbEndpoint endpoint) { return true; }
@Override
public void setClientData(Object data) { }
@Override
public boolean queue(ByteBuffer buffer, int length) { return true; }
}
@Test
public void readQueue() throws Exception {
UsbDeviceConnection usbDeviceConnection = mock(UsbDeviceConnection.class);
DummySerialDriver driver = new DummySerialDriver();
CommonUsbSerialPort port = (CommonUsbSerialPort) driver.getPorts().get(0);
// set before open
port.setReadQueue(0, 0);
port.setReadQueue(0, -1);
assertThrows(IllegalArgumentException.class, () -> port.setReadQueue(-1, 1));
assertThrows(IllegalArgumentException.class, () -> port.setReadQueue(1, 0));
port.setReadQueue(2, 256);
assertNull(port.mReadQueueRequests);
// change after open
port.open(usbDeviceConnection);
assertNotNull(port.mReadQueueRequests);
assertEquals(2, port.mReadQueueRequests.size());
assertThrows(IllegalStateException.class, () -> port.setReadQueue(1, 256));
port.setReadQueue(3, 256);
assertEquals(3, port.mReadQueueRequests.size());
assertThrows(IllegalStateException.class, () -> port.setReadQueue(3, 128));
assertThrows(IllegalStateException.class, () -> port.setReadQueue(3, 512));
// set after open
port.close();
port.setReadQueue(0, 0);
port.open(usbDeviceConnection);
assertNull(port.mReadQueueRequests);
port.setReadQueue(3, 256);
// retain over close
port.close();
assertNull(port.mReadQueueRequests);
port.open(usbDeviceConnection);
assertEquals(3, port.mReadQueueRequests.size());
}
}