[skywalking] branch master updated: improve ContextManager.stopSpan performance: call ThreadLocal only once (#3068)

[wusheng]

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wusheng pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/skywalking.git


The following commit(s) were added to refs/heads/master by this push:
     new c7916d9  improve ContextManager.stopSpan performance: call ThreadLocal 
only once (#3068)
c7916d9 is described below

commit c7916d9f2715ff9d3c415f86418d8f81c97a21e7
Author: qxo <qxodr...@gmail.com>
AuthorDate: Thu Jul 18 00:17:04 2019 +0800

    improve ContextManager.stopSpan performance: call ThreadLocal only once 
(#3068)
    
    * improve ContextManager.stopSpan and awaitFinishAsync performance: call 
ThreadLocal only once
    For the [JMH benchmark 
test](https://gitlab.com/qxo1/Common-JMH-benchmark/-/jobs/251025992) :
    On gitlab CI(java 8): call ThreadLocal once vs twice fast over 10%
    My T480 java 8 : fast over 40%; java 11: fast over 50%;
    
    [The JMH benchmark code 
](https://github.com/qxo/Common-JMH-benchmark/blob/master/src/main/java/test/ThreadLocalGetXTimeBenchmark.java)
    
    * Update 
apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/context/ContextManager.java
    
    Co-Authored-By: kezhenxu94 <kezhenx...@163.com>
    
    * Update 
apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/context/ContextManager.java
    
    Co-Authored-By: kezhenxu94 <kezhenx...@163.com>
    
    * Update 
apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/context/ContextManager.java
    
    Co-Authored-By: 吴晟 Wu Sheng <wu.sh...@foxmail.com>
---
 .../apm/agent/core/context/ContextManager.java        | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git 
a/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/context/ContextManager.java
 
b/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/context/ContextManager.java
index 9c3f48d..90ffdb1 100644
--- 
a/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/context/ContextManager.java
+++ 
b/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/context/ContextManager.java
@@ -150,11 +150,12 @@ public class ContextManager implements BootService {
     }
 
     public static AbstractTracerContext awaitFinishAsync(AbstractSpan span) {
-        AbstractSpan activeSpan = activeSpan();
+        final AbstractTracerContext context = get();
+        AbstractSpan activeSpan = context.activeSpan();
         if (span != activeSpan) {
             throw new RuntimeException("Span is not the active in current 
context.");
         }
-        return get().awaitFinishAsync();
+        return context.awaitFinishAsync();
     }
 
     /**
@@ -165,12 +166,22 @@ public class ContextManager implements BootService {
         return get().activeSpan();
     }
 
+    /**
+    * Recommend use ContextManager::stopSpan(AbstractSpan span), because in 
that way, 
+    * the TracingContext core could verify this span is the active one, in 
order to avoid stop unexpected span.
+    * If the current span is hard to get or only could get by low-performance 
way, this stop way is still acceptable.
+    */
     public static void stopSpan() {
-        stopSpan(activeSpan());
+        final AbstractTracerContext context = get();
+        stopSpan(context.activeSpan(),context);
     }
 
     public static void stopSpan(AbstractSpan span) {
-        if (get().stopSpan(span)) {
+        stopSpan(span, get());
+    }
+
+    private static void stopSpan(AbstractSpan span, final 
AbstractTracerContext context) {
+        if (context.stopSpan(span)) {
             CONTEXT.remove();
             RUNTIME_CONTEXT.remove();
         }