Keep Intel C++ from claiming that it is gcc.

[p5sagit/p5-mst-13.2.git] / lib / Benchmark.pm

diff --git a/lib/Benchmark.pm b/lib/Benchmark.pm
index 854851c..24e3390 100644 (file)
--- a/lib/Benchmark.pm
+++ b/lib/Benchmark.pm
@@ -552,6 +552,8 @@ sub timediff {
     for (my $i=0; $i < @$a; ++$i) {
        push(@r, $a->[$i] - $b->[$i]);
     }
+    #die "Bad timediff(): ($r[1] + $r[2]) <= 0 (@$a[1,2]|@$b[1,2])\n"
+    #        if ($r[1] + $r[2]) < 0;
     bless \@r;
 }
 
@@ -717,9 +719,16 @@ sub countit {
     my ($n, $tc);
 
     # First find the minimum $n that gives a significant timing.
+    my $zeros=0;
     for ($n = 1; ; $n *= 2 ) {
        my $td = timeit($n, $code);
        $tc = $td->[1] + $td->[2];
+       if ( $tc <= 0 and $n > 1024 ) {
+           ++$zeros > 16
+               and die "Timing is consistently zero in estimation loop, cannot benchmark. N=$n\n";
+       } else {
+           $zeros = 0;
+       }
        last if $tc > 0.1;
     }
 
@@ -753,7 +762,7 @@ sub countit {
     # with stable times and avoiding extra timeit()s is nice for
     # accuracy's sake.
     $n = int( $n * ( 1.05 * $tmax / $tc ) );
-
+    $zeros=0;
     while () {
        my $td = timeit($n, $code);
        $ntot  += $n;
@@ -764,7 +773,12 @@ sub countit {
        $cstot += $td->[4];
        $ttot = $utot + $stot;
        last if $ttot >= $tmax;
-
+       if ( $ttot <= 0 ) {
+           ++$zeros > 16
+               and die "Timing is consistently zero, cannot benchmark. N=$n\n";
+       } else {
+           $zeros = 0;
+       }
         $ttot = 0.01 if $ttot < 0.01;
        my $r = $tmax / $ttot - 1; # Linear approximation.
        $n = int( $r * $ntot );