diff --git a/arch/x86/scc/icc.c b/arch/x86/scc/icc.c
index ecb71e3a..e0825836 100644
--- a/arch/x86/scc/icc.c
+++ b/arch/x86/scc/icc.c
@@ -210,7 +210,7 @@ int icc_halt(void)
 	return 0;
 }
 
-#define ROUNDS 100000
+#define ROUNDS 10000
 
 int icc_mail_ping( void )
 {	
@@ -271,6 +271,61 @@ int icc_mail_ping( void )
 	return 0;
 }
 
+
+int icc_mail_ping_irq( void )
+{
+	/* return if not core 0 */
+	if( my_ue ) return;
+
+	uint32_t flags;
+	uint64_t timer;
+	int rem_rank = (my_ue+1)%2;
+	int i;
+	iRCCE_MAIL_HEADER* recv_header = NULL;
+
+	kprintf( "Hello from mail_ping ... \n" );
+	
+	// disable interrupts
+	flags = irq_nested_disable();
+	
+	for( i=0; i<ROUNDS+1; ++i ) {
+		if( my_ue == 0 ) {
+			/* send ping request */ 
+			iRCCE_mail_send(0, PING_REQ, 0, NULL, rem_rank);
+		
+
+			/* send interrupt */
+			icc_send_irq(rem_rank);
+			
+			/* wait for response */
+			do {
+				iRCCE_mail_recv(&recv_header);
+			} while( !recv_header );
+
+			/* release mail */
+			iRCCE_mail_release(&recv_header);
+		}
+	
+		/* start timer in first round */
+		if( i == 0 ) timer = rdtsc();
+
+	}
+
+	/* stop timer */
+	timer = rdtsc() - timer;
+
+
+	kprintf( "timer = %d\n", timer );
+	if( my_ue == 0 ) {
+		kprintf( "mail_pingpong needs in average %f µsec (%d ticks)!\n",
+				timer/(2.0*ROUNDS*533), timer/(2*ROUNDS) );
+	}
+
+	irq_nested_enable(flags);
+
+	return 0;
+}
+
 void icc_mail_check(void)
 {
 	iRCCE_MAIL_HEADER* header = NULL;
@@ -279,18 +334,24 @@ void icc_mail_check(void)
 
 	// empty mailbox and interpret headers
 	while( 	(res = iRCCE_mail_recv( &header )) == iRCCE_SUCCESS ) {
-		if( header->tag == 1 ) {
-			iRCCE_mail_send( 0, 2, 0, NULL, header->source );	
-		}
-		else if( header->tag == iRCCE_ANYLENGTH ) {
+		switch( header->tag ) {
+		case iRCCE_ANYLENGTH:
 			recv_buffer = (char*)kmalloc( header->size );
-			iRCCE_irecv( recv_buffer, header->size, header->source, NULL );
-			iRCCE_mail_send( 0, 2, 0, NULL, header->source );	
-		}
-		else if( header->tag == iRCCE_ANYLENGTH_PIGGYBACK ) {
-			iRCCE_mail_send( 0, 2, 0, NULL, header->source );
+			iRCCE_irecv(recv_buffer, header->size, 
+					header->source, NULL );
+			iRCCE_mail_send(0, 2, 0, NULL, header->source);	
+			break;
+
+		case iRCCE_ANYLENGTH_PIGGYBACK:
+			iRCCE_mail_send(0, 2, 0, NULL, header->source);
+			break;	
+
+		case PING_REQ:
+			iRCCE_mail_send(0, PING_RESP, 0, NULL, header->source);
+			break;
 		}
 
+
 		iRCCE_mail_release( &header );
 	}
 }
diff --git a/kernel/tests.c b/kernel/tests.c
index e3528a7b..6d5a0e72 100644
--- a/kernel/tests.c
+++ b/kernel/tests.c
@@ -88,7 +88,8 @@ static int STDCALL foo(void* arg)
 
 #ifdef CONFIG_ROCKCREEK
 int STDCALL mail_ping(void* arg) {
-		icc_mail_ping();        
+	//	icc_mail_ping();        
+		icc_mail_ping_irq();        
 		icc_halt();
 
 	return 0;