From 273d70e6d992c80dad69b0198cb21577ad7b3ba2 Mon Sep 17 00:00:00 2001
From: Miguel Sofer <miguel.sofer@gmail.com>
Date: Tue, 30 Mar 2004 19:17:55 +0000
Subject: 	* generic/tclExecute.c (TEBC): reverting to the previous
 method 	for async tests in TEBC, as the new method turned out to be
 too 	costly. Async tests now run every 64 instructions.

---
 ChangeLog            |  6 ++++++
 generic/tclExecute.c | 50 ++++++++++++++++++++++++++++++++++++--------------
 2 files changed, 42 insertions(+), 14 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 5848e79..e7e26b1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 2004-03-30  Miguel Sofer <msofer@users.sf.net>
 
+	* generic/tclExecute.c (TEBC): reverting to the previous method
+	for async tests in TEBC, as the new method turned out to be too
+	costly. Async tests now run every 64 instructions.
+	
+2004-03-30  Miguel Sofer <msofer@users.sf.net>
+
 	* generic/tclCompile.c:     New instruction code INST_START_CMD
 	* generic/tclCompile.h:     that allows checking the bytecode's  
 	* generic/tclExecute.c:     validity [Bug 729692] and the interp's  
diff --git a/generic/tclExecute.c b/generic/tclExecute.c
index 3ff411d..5a13482 100644
--- a/generic/tclExecute.c
+++ b/generic/tclExecute.c
@@ -11,7 +11,7 @@
  * See the file "license.terms" for information on usage and redistribution
  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclExecute.c,v 1.122 2004/03/30 16:22:21 msofer Exp $
+ * RCS: @(#) $Id: tclExecute.c,v 1.123 2004/03/30 19:17:57 msofer Exp $
  */
 
 #include "tclInt.h"
@@ -61,6 +61,16 @@ int errno;
 #   endif /* MAXDOUBLE */
 #endif /* !DBL_MAX */
 
+/*
+ * A mask (should be 2**n-1) that is used to work out when the
+ * bytecode engine should call Tcl_AsyncReady() to see whether there
+ * is a signal that needs handling.
+ */
+
+#ifndef ASYNC_CHECK_COUNT_MASK
+#   define ASYNC_CHECK_COUNT_MASK	63
+#endif /* !ASYNC_CHECK_COUNT_MASK */
+
 
 /*
  * Boolean flag indicating whether the Tcl bytecode interpreter has been
@@ -1089,6 +1099,8 @@ TclExecuteByteCode(interp, codePtr)
     int traceInstructions = (tclTraceExec == 3);
     char cmdNameBuf[21];
 #endif
+    int instructionCount = 0;	/* Counter that is used to work out
+				 * when to call Tcl_AsyncReady() */
     Namespace *namespacePtr;
     int codeCompileEpoch = codePtr->compileEpoch;
     int codeNsEpoch = codePtr->nsEpoch;
@@ -1213,21 +1225,23 @@ TclExecuteByteCode(interp, codePtr)
     iPtr->stats.instructionCount[*pc]++;
 #endif
 
-    switch (*pc) {
-    case INST_START_CMD:
-	/*
-	 * Check for asynchronous handlers [Bug 746722].
-	 */
+    /*
+     * Check for asynchronous handlers [Bug 746722]; we
+     * do the check every ASYNC_CHECK_COUNT_MASK instruction,
+     * of the form (2**n-1).
+     */
 
-	if (Tcl_AsyncReady()) {
-	    DECACHE_STACK_INFO();
-	    result = Tcl_AsyncInvoke(interp, result);
-	    CACHE_STACK_INFO();
-	    if (result == TCL_ERROR) {
-		goto checkForCatch;
-	    }
+    if (!(instructionCount++ & ASYNC_CHECK_COUNT_MASK) && Tcl_AsyncReady()) {
+	DECACHE_STACK_INFO();
+	result = Tcl_AsyncInvoke(interp, result);
+	CACHE_STACK_INFO();
+	if (result == TCL_ERROR) {
+	    goto checkForCatch;
 	}
-	
+    }
+
+    switch (*pc) {
+    case INST_START_CMD:
 	if ((!(iPtr->flags & DELETED)
 		    && (codeCompileEpoch == iPtr->compileEpoch)
 		    && (codeNsEpoch == namespacePtr->resolverEpoch))
@@ -1551,6 +1565,14 @@ TclExecuteByteCode(interp, codePtr)
 	    preservedStackRefCountPtr = (char **) (eePtr->stackPtr-1);
 	    ++*preservedStackRefCountPtr;
 
+ 	    /*
+	     * Reset the instructionCount variable, since we're about
+	     * to check for async stuff anyway while processing
+	     * TclEvalObjvInternal.
+	     */
+
+	    instructionCount = 1;
+
 	    /*
 	     * Finally, let TclEvalObjvInternal handle the command. 
 	     */
-- 
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