Second attempt with various improvements (#510)

* Initial chunked impl

* Bytes instead of chars

* Improved number parsing

* Custom hashmap

* Graal and some tuning

* Fix segmenting

* Fix casing

* Unsafe

* Inlining hash calc

* Improved loop

* Cleanup

* Speeding up equals

* Simplifying hash

* Replace concurrenthashmap with lock

* Small changes

* Script reorg

* Native

* Lots of inlining and improvements

* Add back length check

* Fixes

* Small changes

---------

Co-authored-by: Jamal Mulla <[email protected]>

Author: JamalMulla

calculate_average_JamalMulla.sh

@@ -15,5 +15,11 @@
 #  limitations under the License.
 #
 
-JAVA_OPTS="--enable-preview -XX:+UnlockExperimentalVMOptions -XX:+TrustFinalNonStaticFields -XX:+UseTransparentHugePages"
-java $JAVA_OPTS --class-path target/average-1.0.0-SNAPSHOT.jar dev.morling.onebrc.CalculateAverage_JamalMulla
+
+
+if [ -f target/CalculateAverage_JamalMulla_image ]; then
+    target/CalculateAverage_JamalMulla_image
+else
+    JAVA_OPTS="--enable-preview -XX:+UnlockExperimentalVMOptions -XX:+TrustFinalNonStaticFields -XX:+UseTransparentHugePages -XX:-TieredCompilation"
+    java $JAVA_OPTS --class-path target/average-1.0.0-SNAPSHOT.jar dev.morling.onebrc.CalculateAverage_JamalMulla
+fi

prepare_JamalMulla.sh

@@ -16,4 +16,10 @@
 #
 
 source "$HOME/.sdkman/bin/sdkman-init.sh"
-sdk use java 21.0.1-graal 1>&2
+sdk use java 21.0.2-graal 1>&2
+
+# ./mvnw clean verify removes target/ and will re-trigger native image creation.
+if [ ! -f target/CalculateAverage_JamalMulla_image ]; then
+    NATIVE_IMAGE_OPTS="--gc=epsilon -O3 -march=native --enable-preview --strict-image-heap --link-at-build-time -R:MaxHeapSize=64m -da -dsa --no-fallback --initialize-at-build-time=dev.morling.onebrc.CalculateAverage_JamalMulla"
+    native-image $NATIVE_IMAGE_OPTS -cp target/average-1.0.0-SNAPSHOT.jar -o target/CalculateAverage_JamalMulla_image dev.morling.onebrc.CalculateAverage_JamalMulla
+fi