Index: src/protocol/http/org/apache/jmeter/protocol/http/sampler/HTTPHC4Impl.java
===================================================================
--- src/protocol/http/org/apache/jmeter/protocol/http/sampler/HTTPHC4Impl.java	(revision 1825273)
+++ src/protocol/http/org/apache/jmeter/protocol/http/sampler/HTTPHC4Impl.java	(working copy)
@@ -483,8 +483,6 @@
 
     private volatile HttpUriRequest currentRequest; // Accessed from multiple threads
 
-    private volatile boolean resetSSLContext;
-
     protected HTTPHC4Impl(HTTPSamplerBase testElement) {
         super(testElement);
     }
@@ -539,6 +537,7 @@
             log.debug("Start : sample {} method {} followingRedirect {} depth {}", 
                     url, method, areFollowingRedirect, frameDepth);            
         }
+        JMeterVariables jMeterVariables = JMeterContextService.getContext().getVariables();
 
         HTTPSampleResult res = createSampleResult(url, method);
 
@@ -549,7 +548,7 @@
         clientContext.setAttribute(CONTEXT_ATTRIBUTE_AUTH_MANAGER, getAuthManager());
 
         try {
-            httpClient = setupClient(url, clientContext);
+            httpClient = setupClient(jMeterVariables, url, clientContext);
             URI uri = url.toURI();
             if (method.equals(HTTPConstants.POST)) {
                 httpRequest = new HttpPost(uri);
@@ -589,7 +588,7 @@
             return res;
         }
 
-        setupClientContextBeforeSample(localContext);
+        setupClientContextBeforeSample(jMeterVariables, localContext);
         
         res.sampleStart();
 
@@ -609,7 +608,7 @@
 
             // Needs to be done after execute to pick up all the headers
             final HttpRequest request = (HttpRequest) localContext.getAttribute(HttpCoreContext.HTTP_REQUEST);
-            extractClientContextAfterSample(localContext);
+            extractClientContextAfterSample(jMeterVariables, localContext);
             // We've finished with the request, so we can add the LocalAddress to it for display
             if (localAddress != null) {
                 request.addHeader(HEADER_LOCAL_ADDRESS, localAddress.toString());
@@ -718,14 +717,14 @@
     /**
      * Store in JMeter Variables the UserToken so that the SSL context is reused
      * See <a href="https://bz.apache.org/bugzilla/show_bug.cgi?id=57804">Bug 57804</a>
+     * @param jMeterVariables {@link JMeterVariables}
      * @param localContext {@link HttpContext}
      */
-    private void extractClientContextAfterSample(HttpContext localContext) {
+    private void extractClientContextAfterSample(JMeterVariables jMeterVariables, HttpContext localContext) {
         Object userToken = localContext.getAttribute(HttpClientContext.USER_TOKEN);
         if(userToken != null) {
             log.debug("Extracted from HttpContext user token:{} storing it as JMeter variable:{}", userToken, JMETER_VARIABLE_USER_TOKEN);
             // During recording JMeterContextService.getContext().getVariables() is null
-            JMeterVariables jMeterVariables = JMeterContextService.getContext().getVariables();
             if (jMeterVariables != null) {
                 jMeterVariables.putObject(JMETER_VARIABLE_USER_TOKEN, userToken); 
             }
@@ -735,12 +734,12 @@
     /**
      * Configure the UserToken so that the SSL context is reused
      * See <a href="https://bz.apache.org/bugzilla/show_bug.cgi?id=57804">Bug 57804</a>
+     * @param jMeterVariables {@link JMeterVariables}
      * @param localContext {@link HttpContext}
      */
-    private void setupClientContextBeforeSample(HttpContext localContext) {
+    private void setupClientContextBeforeSample(JMeterVariables jMeterVariables, HttpContext localContext) {
         Object userToken = null;
         // During recording JMeterContextService.getContext().getVariables() is null
-        JMeterVariables jMeterVariables = JMeterContextService.getContext().getVariables();
         if(jMeterVariables != null) {
             userToken = jMeterVariables.getObject(JMETER_VARIABLE_USER_TOKEN);            
         }
@@ -934,7 +933,7 @@
         }
     }
 
-    private CloseableHttpClient setupClient(URL url, HttpClientContext clientContext) throws GeneralSecurityException {
+    private CloseableHttpClient setupClient(JMeterVariables jMeterVariables, URL url, HttpClientContext clientContext) throws GeneralSecurityException {
 
         Map<HttpClientKey, Pair<CloseableHttpClient, PoolingHttpClientConnectionManager>> mapHttpClientPerHttpClientKey = 
                 HTTPCLIENTS_CACHE_PER_THREAD_AND_HTTPCLIENTKEY.get();
@@ -972,7 +971,7 @@
             httpClient = pair != null ? pair.getLeft() : null;
         }
 
-        resetSSLStateIfNeeded(url, clientContext, pair);
+        resetStateIfNeeded(jMeterVariables, clientContext, mapHttpClientPerHttpClientKey);
 
         if (httpClient == null) { // One-time init for this client
             DnsResolver resolver = this.testElement.getDNSResolver();
@@ -1080,21 +1079,36 @@
      *  <li>Close current Idle or Expired connections that hold SSL State</li>
      *  <li>Remove HttpClientContext.USER_TOKEN from {@link HttpClientContext}</li>
      * </ul>
-     * @param url {@link URL}
+     * @param jMeterVariables {@link JMeterVariables}
      * @param clientContext {@link HttpClientContext}
-     * @param pair {@link Pair} holding {@link CloseableHttpClient} and {@link PoolingHttpClientConnectionManager}
+     * @param mapHttpClientPerHttpClientKey Map of {@link Pair} holding {@link CloseableHttpClient} and {@link PoolingHttpClientConnectionManager}
      */
-    private void resetSSLStateIfNeeded(URL url, HttpClientContext clientContext,
-            Pair<CloseableHttpClient, PoolingHttpClientConnectionManager> pair) {
-        if (resetSSLContext && HTTPConstants.PROTOCOL_HTTPS.equalsIgnoreCase(url.getProtocol())) {
-            if(pair != null) {
-                PoolingHttpClientConnectionManager poolingHttpClientConnectionManager = pair.getRight();
-                poolingHttpClientConnectionManager.closeExpiredConnections();
-                poolingHttpClientConnectionManager.closeIdleConnections(1L, TimeUnit.MICROSECONDS);
-            }
+    private void resetStateIfNeeded(JMeterVariables jMeterVariables, 
+            HttpClientContext clientContext,
+            Map<HttpClientKey, Pair<CloseableHttpClient, PoolingHttpClientConnectionManager>> mapHttpClientPerHttpClientKey) {
+        if (resetSSLContext.get()) {
+            closeCurrentConnections(mapHttpClientPerHttpClientKey);
             clientContext.removeAttribute(HttpClientContext.USER_TOKEN);
             ((JsseSSLManager) SSLManager.getInstance()).resetContext();
-            resetSSLContext = false;
+            resetSSLContext.set(false);
+        }
+        if (closeConnections.get()) {
+            closeCurrentConnections(mapHttpClientPerHttpClientKey);
+            clientContext.removeAttribute(HttpClientContext.USER_TOKEN);
+            closeConnections.set(false);
+        }
+    }
+
+    /**
+     * @param mapHttpClientPerHttpClientKey
+     */
+    private void closeCurrentConnections(
+            Map<HttpClientKey, Pair<CloseableHttpClient, PoolingHttpClientConnectionManager>> mapHttpClientPerHttpClientKey) {
+        for (Pair<CloseableHttpClient, PoolingHttpClientConnectionManager> pair :
+                mapHttpClientPerHttpClientKey.values()) {
+            PoolingHttpClientConnectionManager poolingHttpClientConnectionManager = pair.getRight();
+            poolingHttpClientConnectionManager.closeExpiredConnections();
+            poolingHttpClientConnectionManager.closeIdleConnections(1L, TimeUnit.MICROSECONDS);
         }
     }
 
@@ -1700,8 +1714,11 @@
 
     @Override
     protected void notifyFirstSampleAfterLoopRestart() {
-        log.debug("notifyFirstSampleAfterLoopRestart");
-        resetSSLContext = !USE_CACHED_SSL_CONTEXT;
+        log.debug("notifyFirstSampleAfterLoopRestart called "
+                + "with config(reuse.http.connections={}, https.use.cached.ssl.context={})",
+                REUSE_HTTP_CONNECTIONS, USE_CACHED_SSL_CONTEXT);
+        closeConnections.set(!REUSE_HTTP_CONNECTIONS);
+        resetSSLContext.set(!USE_CACHED_SSL_CONTEXT);
     }
 
     @Override
Index: src/protocol/http/org/apache/jmeter/protocol/http/sampler/HTTPHCAbstractImpl.java
===================================================================
--- src/protocol/http/org/apache/jmeter/protocol/http/sampler/HTTPHCAbstractImpl.java	(revision 1825265)
+++ src/protocol/http/org/apache/jmeter/protocol/http/sampler/HTTPHCAbstractImpl.java	(working copy)
@@ -78,10 +78,28 @@
     // -1 means not defined
     protected static final int SO_TIMEOUT = JMeterUtils.getPropDefault("httpclient.timeout", -1);
     
+    // Control reuse of HTTP connections in subsequent iterations
+    protected static final boolean REUSE_HTTP_CONNECTIONS = 
+            JMeterUtils.getPropDefault("reuse.http.connections", false);//$NON-NLS-1$
+
     // Control reuse of cached SSL Context in subsequent iterations
     protected static final boolean USE_CACHED_SSL_CONTEXT = 
             JMeterUtils.getPropDefault("https.use.cached.ssl.context", true);//$NON-NLS-1$
 
+    /**
+     *  Whether SSL State/Context should be reset
+     *  Shared state for any HC based implementation, because SSL contexts are the same 
+     */
+    protected static final ThreadLocal<Boolean> resetSSLContext =
+            ThreadLocal.withInitial(() -> Boolean.FALSE);
+
+    /**
+     *  Whether connections should be closed
+     *  Shared state for any HC based implementation, 
+     */
+    protected static final ThreadLocal<Boolean> closeConnections =
+            ThreadLocal.withInitial(() -> Boolean.FALSE);
+    
     static {
         if(!StringUtils.isEmpty(JMeterUtils.getProperty("httpclient.timeout"))) { //$NON-NLS-1$
             log.warn("You're using property 'httpclient.timeout' that will soon be deprecated for HttpClient3.1, you should either set "
Index: src/protocol/http/org/apache/jmeter/protocol/http/sampler/HTTPSamplerProxy.java
===================================================================
--- src/protocol/http/org/apache/jmeter/protocol/http/sampler/HTTPSamplerProxy.java	(revision 1825265)
+++ src/protocol/http/org/apache/jmeter/protocol/http/sampler/HTTPSamplerProxy.java	(working copy)
@@ -36,8 +36,6 @@
 
     private transient HTTPAbstractImpl impl;
     
-    private transient volatile boolean notifyFirstSampleAfterLoopRestart;
-
     public HTTPSamplerProxy(){
         super();
     }
@@ -66,11 +64,6 @@
                 return errorResult(ex, new HTTPSampleResult());
             }
         }
-        // see https://bz.apache.org/bugzilla/show_bug.cgi?id=51380
-        if(notifyFirstSampleAfterLoopRestart) {
-            impl.notifyFirstSampleAfterLoopRestart();
-            notifyFirstSampleAfterLoopRestart = false;
-        }
         return impl.sample(u, method, areFollowingRedirect, depth);
     }
 
@@ -97,6 +90,8 @@
      */
     @Override
     public void testIterationStart(LoopIterationEvent event) {
-        notifyFirstSampleAfterLoopRestart = true;
+        if (impl != null) {
+            impl.notifyFirstSampleAfterLoopRestart();
+        }
     }
 }