diff --git a/tests/benchmark/src/java/com/android/microdroid/benchmark/MicrodroidBenchmarks.java b/tests/benchmark/src/java/com/android/microdroid/benchmark/MicrodroidBenchmarks.java
index 612b1ae..4b11d77 100644
--- a/tests/benchmark/src/java/com/android/microdroid/benchmark/MicrodroidBenchmarks.java
+++ b/tests/benchmark/src/java/com/android/microdroid/benchmark/MicrodroidBenchmarks.java
@@ -29,6 +29,8 @@
 import android.app.Instrumentation;
 import android.os.Bundle;
 import android.os.ParcelFileDescriptor;
+import android.os.ParcelFileDescriptor.AutoCloseInputStream;
+import android.os.ParcelFileDescriptor.AutoCloseOutputStream;
 import android.os.Process;
 import android.os.RemoteException;
 import android.system.virtualmachine.VirtualMachine;
@@ -40,6 +42,7 @@
 import com.android.microdroid.test.common.ProcessUtil;
 import com.android.microdroid.test.device.MicrodroidDeviceTestBase;
 import com.android.microdroid.testservice.IBenchmarkService;
+import com.android.microdroid.testservice.ITestService;
 
 import org.junit.Before;
 import org.junit.Rule;
@@ -48,8 +51,14 @@
 import org.junit.runner.RunWith;
 import org.junit.runners.Parameterized;
 
+import java.io.BufferedReader;
 import java.io.File;
 import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.io.Writer;
 import java.nio.file.Files;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -616,4 +625,66 @@
         }
         reportMetrics(requestLatencies, "latency/rpcbinder", "us");
     }
+
+    @Test
+    public void testVsockLatency() throws Exception {
+        final int NUM_WARMUPS = 10;
+        final int NUM_REQUESTS = 10_000;
+
+        VirtualMachineConfig config =
+                newVmConfigBuilder()
+                        .setPayloadBinaryName("MicrodroidTestNativeLib.so")
+                        .setDebugLevel(DEBUG_LEVEL_NONE)
+                        .build();
+
+        List<Double> requestLatencies = new ArrayList<>(IO_TEST_TRIAL_COUNT * NUM_REQUESTS);
+        for (int i = 0; i < IO_TEST_TRIAL_COUNT; ++i) {
+            VirtualMachine vm = forceCreateNewVirtualMachine("test_vm_latency" + i, config);
+            TestResults testResults =
+                    runVmTestService(
+                            TAG,
+                            vm,
+                            (ts, tr) -> {
+                                ts.runEchoReverseServer();
+                                ParcelFileDescriptor pfd =
+                                        vm.connectVsock(ITestService.ECHO_REVERSE_PORT);
+                                try (InputStream input = new AutoCloseInputStream(pfd);
+                                        OutputStream output = new AutoCloseOutputStream(pfd)) {
+                                    BufferedReader reader =
+                                            new BufferedReader(new InputStreamReader(input));
+                                    Writer writer = new OutputStreamWriter(output);
+
+                                    // Correctness check.
+                                    writer.write("hello\n");
+                                    writer.flush();
+                                    tr.mFileContent = reader.readLine().trim();
+
+                                    // Warmup.
+                                    for (int j = 0; j < NUM_WARMUPS; ++j) {
+                                        String text = "test" + j + "\n";
+                                        writer.write(text);
+                                        writer.flush();
+                                        reader.readLine();
+                                    }
+
+                                    // Measured requests.
+                                    tr.mTimings = new long[NUM_REQUESTS];
+                                    for (int j = 0; j < NUM_REQUESTS; j++) {
+                                        String text = "test" + j + "\n";
+                                        long start = System.nanoTime();
+                                        writer.write(text);
+                                        writer.flush();
+                                        reader.readLine();
+                                        tr.mTimings[j] = System.nanoTime() - start;
+                                    }
+                                }
+                            });
+            testResults.assertNoException();
+            assertThat(testResults.mFileContent).isEqualTo("olleh");
+            for (long duration : testResults.mTimings) {
+                requestLatencies.add((double) duration / NANO_TO_MICRO);
+            }
+        }
+        reportMetrics(requestLatencies, "latency/vsock", "us");
+    }
 }
diff --git a/tests/testapk/src/native/testbinary.cpp b/tests/testapk/src/native/testbinary.cpp
index 365ea75..19d6cd4 100644
--- a/tests/testapk/src/native/testbinary.cpp
+++ b/tests/testapk/src/native/testbinary.cpp
@@ -84,28 +84,26 @@
         return ErrnoError() << "Failed to fdopen";
     }
 
-    char* line = nullptr;
-    size_t size = 0;
-    if (getline(&line, &size, input) < 0) {
-        return ErrnoError() << "Failed to read";
+    // Run forever, reverse one line at a time.
+    while (true) {
+        char* line = nullptr;
+        size_t size = 0;
+        if (getline(&line, &size, input) < 0) {
+            return ErrnoError() << "Failed to read";
+        }
+
+        std::string_view original = line;
+        if (!original.empty() && original.back() == '\n') {
+            original = original.substr(0, original.size() - 1);
+        }
+
+        std::string reversed(original.rbegin(), original.rend());
+        reversed += "\n";
+
+        if (write(connect_fd, reversed.data(), reversed.size()) < 0) {
+            return ErrnoError() << "Failed to write";
+        }
     }
-
-    if (fclose(input) != 0) {
-        return ErrnoError() << "Failed to fclose";
-    }
-
-    std::string_view original = line;
-    if (!original.empty() && original.back() == '\n') {
-        original = original.substr(0, original.size() - 1);
-    }
-
-    std::string reversed(original.rbegin(), original.rend());
-
-    if (write(connect_fd, reversed.data(), reversed.size()) < 0) {
-        return ErrnoError() << "Failed to write";
-    }
-
-    return {};
 }
 
 Result<void> start_echo_reverse_server() {