patch 8.2.5036: using two counters for timeout check in NFA engine
Problem: Using two counters for timeout check in NFA engine.
Solution: Use only one counter. Tune the counts based on guessing.
diff --git a/src/regexp_nfa.c b/src/regexp_nfa.c
index 1e7cd9b..9c521f3 100644
--- a/src/regexp_nfa.c
+++ b/src/regexp_nfa.c
@@ -4053,7 +4053,6 @@
#ifdef FEAT_RELTIME
static proftime_T *nfa_time_limit;
static int *nfa_timed_out;
-static int nfa_time_count;
#endif
static void copy_sub(regsub_T *to, regsub_T *from);
@@ -5646,22 +5645,26 @@
}
#ifdef FEAT_RELTIME
+/*
+ * Check if we are past the time limit, if there is one.
+ * To reduce overhead, only check one in "count" times.
+ */
static int
-nfa_did_time_out()
+nfa_did_time_out(int count)
{
static int tm_count = 0;
- // Check for timeout once in 800 times to avoid excessive overhead from
- // reading the clock. The value has been picked to check about once per
- // msec on a modern CPU.
+ // Check for timeout once in "count" times to avoid excessive overhead from
+ // reading the clock.
if (nfa_time_limit != NULL)
{
- if (tm_count == 800)
+ if (tm_count >= count)
{
if (profile_passed_limit(nfa_time_limit))
{
if (nfa_timed_out != NULL)
*nfa_timed_out = TRUE;
+ tm_count = 99999;
return TRUE;
}
// Only reset the count when not timed out, so that when it did
@@ -5722,7 +5725,8 @@
if (got_int)
return FALSE;
#ifdef FEAT_RELTIME
- if (nfa_did_time_out())
+ // Check relatively often here, since this is the toplevel matching.
+ if (nfa_did_time_out(100))
return FALSE;
#endif
@@ -5876,12 +5880,9 @@
if (got_int)
break;
#ifdef FEAT_RELTIME
- if (nfa_time_limit != NULL && ++nfa_time_count == 20)
- {
- nfa_time_count = 0;
- if (nfa_did_time_out())
- break;
- }
+ // do not check very often here, since this is a loop in a loop
+ if (nfa_did_time_out(2000))
+ break;
#endif
t = &thislist->t[listidx];
@@ -7126,13 +7127,9 @@
if (got_int)
break;
#ifdef FEAT_RELTIME
- // Check for timeout once in a twenty times to avoid overhead.
- if (nfa_time_limit != NULL && ++nfa_time_count == 20)
- {
- nfa_time_count = 0;
- if (nfa_did_time_out())
- break;
- }
+ // check regularly but not too often here
+ if (nfa_did_time_out(800))
+ break;
#endif
}
@@ -7178,7 +7175,6 @@
#ifdef FEAT_RELTIME
nfa_time_limit = tm;
nfa_timed_out = timed_out;
- nfa_time_count = 0;
#endif
#ifdef ENABLE_LOG