test/hotspot/jtreg/runtime/appcds/TestCommon.java

@@ -143,10 +143,19 @@
         String[] cmdLine = cmd.toArray(new String[cmd.size()]);
         ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(true, cmdLine);
         return executeAndLog(pb, "dump");
     }
 
+    // This allows you to run the AppCDS tests with JFR enabled at runtime (though not at
+    // dump time, as that's uncommon for typical AppCDS users).
+    //
+    // To run in this special mode, specify the following in your jtreg command-line
+    //    -vmoptions:-Dtest.cds.run.with.jfr=true
+    //
+    // Some AppCDS tests are not compatible with this mode. See the group
+    // hotspot_appcds_with_jfr in ../../TEST.ROOT for details.
+    private static final boolean RUN_WITH_JFR = Boolean.getBoolean("test.cds.run.with.jfr");
 
     // Execute JVM using AppCDS archive with specified AppCDSOptions
     public static OutputAnalyzer runWithArchive(AppCDSOptions opts)
         throws Exception {
 

@@ -164,10 +173,26 @@
             cmd.add(opts.appJar);
         }
 
         for (String s : opts.suffix) cmd.add(s);
 
+        if (RUN_WITH_JFR) {
+            boolean usesJFR = false;
+            for (String s : cmd) {
+                if (s.startsWith("-XX:StartFlightRecording=") || s.startsWith("-XX:FlightRecorderOptions")) {
+                    System.out.println("JFR option might have been specified. Don't interfere: " + s);
+                    usesJFR = true;
+                    break;
+                }
+            }
+            if (!usesJFR) {
+                System.out.println("JFR option not specified. Enabling JFR ...");
+                cmd.add(0, "-XX:StartFlightRecording=dumponexit=true");
+                System.out.println(cmd);
+            }
+        }
+
         String[] cmdLine = cmd.toArray(new String[cmd.size()]);
         ProcessBuilder pb = ProcessTools.createJavaProcessBuilder(true, cmdLine);
         return executeAndLog(pb, "exec");
     }