Re: [tomcat] 02/02: LongAdder is a better choice for statistics collection

[Mark Thomas]

Patches welcome if that is an itch someone wants to scratch.

Mark


On 24/01/2023 13:22, Romain Manni-Bucau wrote:

If you care about the (perf) diff, shouldnt tomcat have a config to be able
to disable stats overhead at all (using a Runnable or Counter {incr(),
get()} as abstraction is sufficient) when it is not used (most of the time
in dev+prod - ie not sizing/tuning phases)?

Romain Manni-Bucau
@rmannibucau <https://twitter.com/rmannibucau> |  Blog
<https://rmannibucau.metawerx.net/> | Old Blog
<http://rmannibucau.wordpress.com> | Github <https://github.com/rmannibucau> |
LinkedIn <https://www.linkedin.com/in/rmannibucau> | Book
<https://www.packtpub.com/application-development/java-ee-8-high-performance>


Le mar. 24 janv. 2023 à 14:19, Rémy Maucherat <r...@apache.org> a écrit :

On Tue, Jan 24, 2023 at 1:26 PM <ma...@apache.org> wrote:

This is an automated email from the ASF dual-hosted git repository.

markt pushed a commit to branch 9.0.x
in repository https://gitbox.apache.org/repos/asf/tomcat.git

commit a7bf4d84f753d69acb66f5e45f5bc767a1d55e49
Author: Mark Thomas <ma...@apache.org>
AuthorDate: Tue Jan 24 12:22:01 2023 +0000

     LongAdder is a better choice for statistics collection

Never heard of that before, but I see it's already there in Java 8.

Rémy

---
  java/org/apache/catalina/webresources/Cache.java | 17 +++++++++--------
  1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/java/org/apache/catalina/webresources/Cache.java

b/java/org/apache/catalina/webresources/Cache.java

index 949117f521..4893a289cb 100644
--- a/java/org/apache/catalina/webresources/Cache.java
+++ b/java/org/apache/catalina/webresources/Cache.java
@@ -22,6 +22,7 @@ import java.util.TreeSet;
  import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.ConcurrentMap;
  import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.atomic.LongAdder;

  import org.apache.catalina.WebResource;
  import org.apache.catalina.WebResourceRoot.CacheStrategy;
@@ -48,8 +49,8 @@ public class Cache {
      private int objectMaxSize = (int) maxSize / OBJECT_MAX_SIZE_FACTOR;
      private CacheStrategy cacheStrategy;

-    private AtomicLong lookupCount = new AtomicLong(0);
-    private AtomicLong hitCount = new AtomicLong(0);
+    private LongAdder lookupCount = new LongAdder();
+    private LongAdder hitCount = new LongAdder();

      private final ConcurrentMap<String, CachedResource> resourceCache =

new ConcurrentHashMap<>();

@@ -70,7 +71,7 @@ public class Cache {
              }
          }

-        lookupCount.incrementAndGet();
+        lookupCount.increment();

          CachedResource cacheEntry = resourceCache.get(path);

@@ -138,14 +139,14 @@ public class Cache {
                  cacheEntry.validateResource(useClassLoaderResources);
              }
          } else {
-            hitCount.incrementAndGet();
+            hitCount.increment();
          }

          return cacheEntry;
      }

      protected WebResource[] getResources(String path, boolean

useClassLoaderResources) {

-        lookupCount.incrementAndGet();
+        lookupCount.increment();

          // Don't call noCache(path) since the class loader only caches
          // individual resources. Therefore, always cache collections

here

@@ -196,7 +197,7 @@ public class Cache {
                  cacheEntry.validateResources(useClassLoaderResources);
              }
          } else {
-            hitCount.incrementAndGet();
+            hitCount.increment();
          }

          return cacheEntry.getWebResources();
@@ -291,11 +292,11 @@ public class Cache {
      }

      public long getLookupCount() {
-        return lookupCount.get();
+        return lookupCount.sum();
      }

      public long getHitCount() {
-        return hitCount.get();
+        return hitCount.sum();
      }

      public void setObjectMaxSize(int objectMaxSize) {


---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscr...@tomcat.apache.org
For additional commands, e-mail: dev-h...@tomcat.apache.org

---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscr...@tomcat.apache.org
For additional commands, e-mail: dev-h...@tomcat.apache.org

---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscr...@tomcat.apache.org
For additional commands, e-mail: dev-h...@tomcat.apache.org