Average times and multiple test iterations.

README.md

@@ -3,39 +3,12 @@
 
 ## Examples
 
+Test with 8GB memory:
 ```shell
-java -Xms128g -Xmx128g  -XX:+UseLargePages -XX:+AlwaysPreTouch \
-  -XX:-UseParallelGC -XX:MaxGCPauseMillis=500 -Xgcthreads3  \
-  -jar memstress-0.0.1-all.jar -t 96
+java -Xms10g -Xmx10g -XX:+AlwaysPreTouch -jar memstress-0.0.1-all.jar -t 8
 ```
 
-
+Test with 100GB memory:
 ```shell
-java -Xms144g -Xmx144g  -XX:+UseLargePages -XX:+AlwaysPreTouch \
-  -XX:-UseParallelGC -XX:MaxGCPauseMillis=500 -Xgcthreads3  \
-  -jar memstress-0.0.1-all.jar -t 128
-```
-
-```shell
-java -Xms160g -Xmx160g  -XX:+UseLargePages -XX:+AlwaysPreTouch \
-  -XX:-UseParallelGC -XX:MaxGCPauseMillis=500 -Xgcthreads3  \
-  -jar memstress-0.0.1-all.jar -t 144
-```
-
-```shell
-java -Xms192g -Xmx192g  -XX:+UseLargePages -XX:+AlwaysPreTouch \
-  -XX:-UseParallelGC -XX:MaxGCPauseMillis=500 -Xgcthreads3  \
-  -jar memstress-0.0.1-all.jar -t 160
-```
-
-```shell
-java -Xms240g -Xmx240g  -XX:+UseLargePages -XX:+AlwaysPreTouch \
-  -XX:-UseParallelGC -XX:MaxGCPauseMillis=500 -Xgcthreads3  \
-  -jar memstress-0.0.1-all.jar -t 192
-```
-
-```shell
-java -Xms256g -Xmx256g  -XX:+UseLargePages -XX:+AlwaysPreTouch \
-  -XX:-UseParallelGC -XX:MaxGCPauseMillis=500 -Xgcthreads3  \
-  -jar memstress-0.0.1-all.jar -t 240
+java -Xms128g -Xmx128g -XX:+AlwaysPreTouch -jar memstress-0.0.1-all.jar -t 100
 ```

src/main/java/biz/nellemann/memstress/Application.java

@@ -3,6 +3,8 @@ package biz.nellemann.memstress;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import picocli.CommandLine;
+
+import java.time.Duration;
 import java.util.concurrent.Callable;
 
 @CommandLine.Command(name = "memstress", mixinStandardHelpOptions = true, versionProvider = VersionProvider.class, description = "Memory performance measurement tool.")
@@ -20,14 +22,25 @@ public class Application implements Callable<Integer> {
     @CommandLine.Option(names = { "-d", "--data" }, paramLabel = "NUM", description = "Create this much data (MB) pr. row [default: ${DEFAULT-VALUE}]")
     int maxDataPerRow = 100;
 
+    @CommandLine.Option(names = { "-i", "--iterations" }, paramLabel = "NUM", description = "Iterate test his many times [default: ${DEFAULT-VALUE}]")
+    int iterations = 3;
 
     @Override
     public Integer call() throws Exception {
 
-        MyDatabase database = new MyDatabase(maxTables, maxRowsPerTable, maxDataPerRow);
-        database.write("testDb");
-        database.read("testDb");
-        database.destroy("testDb");
+        long writeTimeMillis = 0;
+        long readTimeMillis = 0;
+
+        for(int i = 1; i <= iterations; i++) {
+            log.info("Starting test {} of {}", i, iterations);
+            MemDatabase database = new MemDatabase(maxTables, maxRowsPerTable, maxDataPerRow);
+            writeTimeMillis += database.write("testDb");
+            readTimeMillis += database.read("testDb");
+            database.destroy("testDb");
+        }
+
+        log.info("Average writing time: {}", Duration.ofMillis(writeTimeMillis / iterations));
+        log.info("Average reading time: {}", Duration.ofMillis(readTimeMillis / iterations));
 
         return 0;
     }

src/main/java/biz/nellemann/memstress/MemDatabase.java

@@ -14,9 +14,9 @@ import java.util.Arrays;
 import java.util.HashMap;
 import java.util.concurrent.atomic.AtomicLong;
 
-public class MyDatabase {
+public class MemDatabase {
 
-    final Logger log = LoggerFactory.getLogger(MyDatabase.class);
+    final Logger log = LoggerFactory.getLogger(MemDatabase.class);
 
     private final int BYTE_SIZE_1MB = 1_000_000;
     private final int BYTE_SIZE_1GB = 1_000_000_000;
@@ -35,7 +35,7 @@ public class MyDatabase {
     private char[] baseCar;
     private byte[] byteBase;
 
-    public MyDatabase(int tables, int rows, int size) {
+    public MemDatabase(int tables, int rows, int size) {
         this.maxTables = tables;
         this.maxRowsPerTable = rows;
         this.maxDataPerRow = size;
@@ -48,7 +48,7 @@ public class MyDatabase {
     }
 
 
-    public void write(String dbName) {
+    public long write(String dbName) {
         Instant instant1 = Instant.now();
         Database database = databaseManager.createDatabase(dbName);
 
@@ -74,11 +74,14 @@ public class MyDatabase {
         }
 
         Instant instant2 = Instant.now();
-        log.info("Done writing {}b to \"{}\" in {}", bytesWritten, dbName, Duration.between(instant1, instant2));
+        Duration duration = Duration.between(instant1, instant2);
+        log.info("Done writing {} bytes -> \"{}\" in {}", bytesWritten, dbName, duration);
+
+        return duration.toMillis();
     }
 
 
-    public void read(String dbName) {
+    public long read(String dbName) {
         Instant instant1 = Instant.now();
         Database database = databaseManager.getDatabase(dbName);
 
@@ -97,8 +100,10 @@ public class MyDatabase {
             });
         }
         Instant instant2 = Instant.now();
-        log.info("Done reading {}b from \"{}\" in {}", bytesRead.get(), dbName, Duration.between(instant1, instant2));
+        Duration duration = Duration.between(instant1, instant2);
+        log.info("Done reading {} bytes <- \"{}\" in {}", bytesRead.get(), dbName, duration);
 
+        return duration.toMillis();
     }