[m-rev.] for review: remove a slow declarative debugger consistency check.

[Ian MacLarty]

On Fri, Apr 15, 2005 at 09:25:40AM +1000, Zoltan Somogyi wrote:
> On 14-Apr-2005, Ian MacLarty <maclarty at cs.mu.OZ.AU> wrote:
> > Remove the search space consistency check from decide_analyser_response/4.
> 
> It would be better to leave the checks in, but execute them only if a flag
> is set, with the flag being clear by default.
> 

Estimated hours taken: 1
Branches: main and 0.12

Only perform a consistency check on the search space if the
MR_DD_CHECK_SEARCH_SPACE C macro is defined.  This check was slowing the
declarative debugger down considerably.  The debugger/declarative/binary_search
test now takes about a second or two, instead of around 5-7 seconds previously
(these are estimates).

browser/declarative_analyser.m:
	Call a wrapper predicate which only performs the check if
	the C macro is defined.

browser/declarative_edt.m:
	Add a wrapper predicate which only performs the check if the
	C macro is defined.

Index: browser//declarative_analyser.m
===================================================================
RCS file: /home/mercury1/repository/mercury/browser/declarative_analyser.m,v
retrieving revision 1.22
diff -u -r1.22 declarative_analyser.m
--- browser//declarative_analyser.m	11 Apr 2005 06:43:33 -0000	1.22
+++ browser//declarative_analyser.m	15 Apr 2005 01:57:14 -0000
@@ -465,10 +465,7 @@
 	is det <= mercury_edt(S, T).
 
 decide_analyser_response(Store, Response, !Analyser) :-
-	% Do a sanity check before the search.  So we can determine afterwards
-	% if the search corrupted the search space at all.
-	% XXX this should be removed at some stage as it's relatively slow.
-	check_search_space_consistency(Store, !.Analyser ^ search_space,
+	maybe_check_search_space_consistency(Store, !.Analyser ^ search_space,
 		"Start of decide_analyser_response"),
 	some [!SearchSpace] (
 		!:SearchSpace = !.Analyser ^ search_space,
@@ -494,10 +491,7 @@
 				!Analyser, Response)
 		)
 	),
-	% Do a sanity check after the search to determine if the search 
-	% corrupted the search space at all. 
-	% XXX this should be removed at some stage as it's relatively slow.
-	check_search_space_consistency(Store, !.Analyser ^ search_space,
+	maybe_check_search_space_consistency(Store, !.Analyser ^ search_space,
 		"End of decide_analyser_response").
 
 :- pred handle_search_response(S::in, search_response::in, 
Index: browser//declarative_edt.m
===================================================================
RCS file: /home/mercury1/repository/mercury/browser/declarative_edt.m,v
retrieving revision 1.6
diff -u -r1.6 declarative_edt.m
--- browser//declarative_edt.m	11 Apr 2005 06:43:33 -0000	1.6
+++ browser//declarative_edt.m	15 Apr 2005 02:33:30 -0000
@@ -487,12 +487,13 @@
 :- pred revise_root(S::in, search_space(T)::in, search_space(T)::out) 
 	is det <= mercury_edt(S, T).
 
-	% Check the consistency of the search space and throw an exception
+	% Check the consistency of the search space if the
+	% MR_DD_CHECK_SEARCH_SPACE C macro is defined.  Throw an exception
 	% if it's not consistent.  Used for assertion checking during
 	% debugging.
 	%
-:- pred check_search_space_consistency(S::in, search_space(T)::in, string::in) 
-	is det <= mercury_edt(S, T).
+:- pred maybe_check_search_space_consistency(S::in, search_space(T)::in,
+	string::in) is det <= mercury_edt(S, T).
 
 	% Return the proc_label for the given suspect.
 	%
@@ -1127,6 +1128,18 @@
 		StopSuspects = []
 	).
 
+maybe_check_search_space_consistency(Store, SearchSpace, Context) :-
+	(
+		should_check_search_space_consistency
+	->
+		check_search_space_consistency(Store, SearchSpace, Context)
+	;
+		true
+	).
+
+:- pred check_search_space_consistency(S::in, search_space(T)::in,
+	string::in) is det <= mercury_edt(S, T).
+
 check_search_space_consistency(Store, SearchSpace, Context) :-
 	(
 		find_inconsistency_in_weights(Store, SearchSpace, Message)
@@ -1136,6 +1149,19 @@
 	;
 		true
 	).
+
+:- pred should_check_search_space_consistency is semidet.
+
+:- pragma foreign_proc("C", 
+	should_check_search_space_consistency, 
+	[will_not_call_mercury, promise_pure, thread_safe],
+"
+	#ifdef MR_DD_CHECK_SEARCH_SPACE
+		SUCCESS_INDICATOR = MR_TRUE;
+	#else
+		SUCCESS_INDICATOR = MR_FALSE;
+	#endif
+").


Ian.
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