01_before

bin/jruby --dev -e "require 'active_support/all'"  9.30s user 0.35s system 186% cpu 5.177 total
bin/jruby --dev -e "require 'active_support/all'"  8.66s user 0.30s system 186% cpu 4.795 total
bin/jruby --dev -e "require 'active_support/all'"  8.76s user 0.32s system 186% cpu 4.860 total
bin/jruby --dev -e "require 'active_support/all'"  8.76s user 0.26s system 184% cpu 4.887 total
bin/jruby --dev -e "require 'active_support/all'"  8.78s user 0.28s system 186% cpu 4.864 total
bin/jruby --dev -e "require 'active_support/all'"  9.01s user 0.28s system 184% cpu 5.046 total
bin/jruby --dev -e "require 'active_support/all'"  9.02s user 0.31s system 185% cpu 5.025 total
bin/jruby --dev -e "require 'active_support/all'"  8.97s user 0.26s system 182% cpu 5.054 total
bin/jruby --dev -e "require 'active_support/all'"  8.75s user 0.34s system 184% cpu 4.919 total
bin/jruby --dev -e "require 'active_support/all'"  8.62s user 0.26s system 182% cpu 4.870 total

02_after

bin/jruby --dev -e "require 'active_support/all'"  8.01s user 0.31s system 175% cpu 4.738 total
bin/jruby --dev -e "require 'active_support/all'"  8.60s user 0.34s system 185% cpu 4.824 total
bin/jruby --dev -e "require 'active_support/all'"  8.32s user 0.36s system 185% cpu 4.688 total
bin/jruby --dev -e "require 'active_support/all'"  8.30s user 0.30s system 184% cpu 4.656 total
bin/jruby --dev -e "require 'active_support/all'"  8.33s user 0.31s system 185% cpu 4.646 total
bin/jruby --dev -e "require 'active_support/all'"  7.82s user 0.27s system 185% cpu 4.370 total
bin/jruby --dev -e "require 'active_support/all'"  8.19s user 0.28s system 185% cpu 4.553 total
bin/jruby --dev -e "require 'active_support/all'"  8.25s user 0.26s system 183% cpu 4.648 total
bin/jruby --dev -e "require 'active_support/all'"  8.17s user 0.31s system 185% cpu 4.572 total
bin/jruby --dev -e "require 'active_support/all'"  8.07s user 0.27s system 184% cpu 4.516 total

toggle.patch

diff --git a/core/src/main/java/org/jruby/RubyClass.java b/core/src/main/java/org/jruby/RubyClass.java
index 9c8d88e..338ab0d 100644
--- a/core/src/main/java/org/jruby/RubyClass.java
+++ b/core/src/main/java/org/jruby/RubyClass.java
@@ -696,12 +696,19 @@ public class RubyClass extends RubyModule {
         }
         else {
             IRubyObject oldExc = runtime.getGlobalVariables().get("$!"); // Save $!
+            boolean lastHooksEnabled = context.isEventHooksEnabled();
+            boolean lastExceptionsEnabled = context.exceptionBacktracesEnabled();
+            context.setEventHooksEnabled(false);
+            context.setExceptionBacktracesEnabled(false);
             try {
                 return checkFuncallExec(context, self, method, args);
             } catch (RaiseException e) {
                 IRubyObject ret = checkFuncallFailed(context, self, method, runtime.getNoMethodError(), args);
                 runtime.getGlobalVariables().set("$!", oldExc); // restore $!
                 return ret;
+            } finally {
+                context.setEventHooksEnabled(lastHooksEnabled);
+                context.setExceptionBacktracesEnabled(lastExceptionsEnabled);
             }
         }
     }
diff --git a/core/src/main/java/org/jruby/exceptions/RaiseException.java b/core/src/main/java/org/jruby/exceptions/RaiseException.java
index cf4098f..91ac5ed 100644
--- a/core/src/main/java/org/jruby/exceptions/RaiseException.java
+++ b/core/src/main/java/org/jruby/exceptions/RaiseException.java
@@ -191,7 +191,7 @@ public class RaiseException extends JumpException {
     }
 
     private void preRaise(ThreadContext context) {
-        preRaise(context, (IRubyObject)null);
+        preRaise(context, (IRubyObject) null);
     }
 
     private void preRaise(ThreadContext context, StackTraceElement[] javaTrace) {
@@ -211,20 +211,23 @@ public class RaiseException extends JumpException {
 
         if (RubyInstanceConfig.LOG_EXCEPTIONS) TraceType.dumpException(exception);
 
-        if (backtrace == null) {
-            exception.prepareBacktrace(context, nativeException);
-        } else {
-            exception.forceBacktrace(backtrace);
-        }
+        if (context.exceptionBacktracesEnabled()) {
+            // System.out.println(String.format("Exception: %s", exception));
+            if (backtrace == null) {
+                exception.prepareBacktrace(context, nativeException);
+            } else {
+                exception.forceBacktrace(backtrace);
+            }
 
-        // call Throwable.setStackTrace so that when RaiseException appears nested inside another exception,
-        // Ruby stack trace gets displayed
+            // call Throwable.setStackTrace so that when RaiseException appears nested inside another exception,
+            // Ruby stack trace gets displayed
 
-        // JRUBY-2673: if wrapping a NativeException, use the actual Java exception's trace as our Java trace
-        if (exception instanceof NativeException) {
-            setStackTrace(((NativeException)exception).getCause().getStackTrace());
-        } else {
-            setStackTrace(RaiseException.javaTraceFromRubyTrace(exception.getBacktraceElements()));
+            // JRUBY-2673: if wrapping a NativeException, use the actual Java exception's trace as our Java trace
+            if (exception instanceof NativeException) {
+                setStackTrace(((NativeException)exception).getCause().getStackTrace());
+            } else {
+                setStackTrace(RaiseException.javaTraceFromRubyTrace(exception.getBacktraceElements()));
+            }
         }
     }
 
diff --git a/core/src/main/java/org/jruby/runtime/ThreadContext.java b/core/src/main/java/org/jruby/runtime/ThreadContext.java
index 9a6d4d8..eed62bf 100644
--- a/core/src/main/java/org/jruby/runtime/ThreadContext.java
+++ b/core/src/main/java/org/jruby/runtime/ThreadContext.java
@@ -121,6 +121,7 @@ public final class ThreadContext {
     private ProfileCollection profileCollection;
 	
     private boolean eventHooksEnabled = true;
+    private boolean exceptionBacktracesEnabled = true;
 
     CallType lastCallType;
 
@@ -739,7 +740,16 @@ public final class ThreadContext {
     public void setEventHooksEnabled(boolean flag) {
         eventHooksEnabled = flag;
     }
-    
+
+    public boolean exceptionBacktracesEnabled() {
+        return exceptionBacktracesEnabled;
+    }
+
+    public void setExceptionBacktracesEnabled(boolean flag) {
+        exceptionBacktracesEnabled = flag;
+    }
+
+
     /**
      * Create an Array with backtrace information.
      * @param level