[igt-dev] [PATCH i-g-t 11/11] trace.pl: Fix request split mode

[Tvrtko Ursulin]

From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Request split mode had several bugs, both in the original version and also
after the recent refactorings.

One big one was that it wasn't considering different submit ports as a
reason to split execution, and also that it was too time based instead of
looking at relevant timelines.

In this refactoring we address the former by using the engine timelines
introduced in the previous patch. Secondary port submissions are moved
to follow the preceding submission as a first step in the correction
process.

In the second step, we add context timelines and use then in a similar
fashion to separate start and end time of coalesced requests. For each
coalesced request we know its boundaries by looking at the engine
timeline (via global seqnos), and we know the previous request it should
only start after, by looking at the context timeline.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Cc: John Harrison <John.C.Harrison at intel.com>
---
 scripts/trace.pl | 129 ++++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 103 insertions(+), 26 deletions(-)

diff --git a/scripts/trace.pl b/scripts/trace.pl
index 768bb015da99..653215819f34 100755
--- a/scripts/trace.pl
+++ b/scripts/trace.pl
@@ -572,41 +572,118 @@ sub sortStart {
 	return $val;
 }
 
-my @sorted_keys = sort sortStart keys %db;
-my $re_sort = 0;
+my $re_sort = 1;
+my @sorted_keys;
 
-die "Database changed size?!" unless scalar(@sorted_keys) == $key_count;
+sub maybe_sort_keys
+{
+	if ($re_sort) {
+		@sorted_keys = sort sortStart keys %db;
+		$re_sort = 0;
+		die "Database changed size?!" unless scalar(@sorted_keys) ==
+						     $key_count;
+	}
+}
 
-foreach my $key (@sorted_keys) {
-	my $ring = $db{$key}->{'ring'};
-	my $end = $db{$key}->{'end'};
+maybe_sort_keys();
+
+my %ctx_timelines;
+
+sub sortContext {
+	my $as = $db{$a}->{'seqno'};
+	my $bs = $db{$b}->{'seqno'};
+	my $val;
 
-	# correct duration of merged batches
-	if ($correct_durations and exists $db{$key}->{'no-end'}) {
+	$val = $as <=> $bs;
+
+	die if $val == 0;
+
+	return $val;
+}
+
+sub get_ctx_timeline {
+	my ($ctx, $ring, $key) = @_;
+	my @timeline;
+
+	return $ctx_timelines{$key} if exists $ctx_timelines{$key};
+
+	@timeline = grep { $db{$_}->{'ring'} == $ring and
+			   $db{$_}->{'ctx'} == $ctx } @sorted_keys;
+	# FIXME seqno restart
+	@timeline = sort sortContext @timeline;
+
+	$ctx_timelines{$key} = \@timeline;
+
+	return \@timeline;
+}
+
+# Split out merged batches if requested.
+if ($correct_durations) {
+	my @port1;
+	my @no_end;
+
+	# Shift port1 requests start time to after the previous port0 context on
+	# the same timeline has finished.
+	@port1 = grep { $db{$_}->{'port'} == 1 } @sorted_keys;
+	foreach my $key (@port1) {
+		my $timeline = get_engine_timeline($db{$key}->{'ring'});
+		my $i = List::Util::first { ${$timeline}[$_] eq $key } 0..$#{$timeline};
+		my $prev_key;
+		my $start;
+
+		die if $i == 0;
+
+		$prev_key = ${$timeline}[$i - 1];
+		$start = $db{$prev_key}->{'end'};
+		$db{$key}->{'start'} = $start;
+		die if $start > $db{$key}->{'end'};
+
+		# Timeline has just been modified so we'll need to adjust it.
+		# First delete the current key from the timeline.
+		splice @{$timeline}, $i, 1;
+		# Now find the new correct position for the key and insert it
+		# there.
+		while ($i < $#{$timeline}) {
+			last if $db{${$timeline}[$i]}->{'global'} >= $db{$key}->{'global'};
+			$i = $i + 1;
+		}
+		splice @{$timeline}, $i, 0, $key;
+		$re_sort = 1;
+	}
+
+	maybe_sort_keys();
+
+	# Batch with no-end (no request_out) means it was submitted as part of
+	# colaesced context. This means it's start time should be set to the end
+	# time of a precedeing request on this timeline.
+	@no_end = grep { exists $db{$_}->{'no-end'} } @sorted_keys;
+	foreach my $key (@no_end) {
 		my $ctx = $db{$key}->{'ctx'};
-		my $seqno = $db{$key}->{'seqno'};
-		my $start = $db{$key}->{'start'};
-		my $next_key;
-		my $i = 1;
-
-		do {
-			$next_key = db_key($ring, $ctx, $seqno + $i);
-			$i++;
-		} until (exists $db{$next_key} or $i > $key_count);  # ugly stop hack
-
-		# 20us tolerance
-		if (exists $db{$next_key} and $db{$next_key}->{'start'} < $start + 20) {
-			my $notify = $db{$key}->{'notify'};
+		my $ring = $db{$key}->{'ring'};
+		my $tkey = $ctx . '/' . $ring;
+		my $timeline = get_ctx_timeline($ctx, $ring, $tkey);
+		my $i;
+
+		$i = List::Util::first { ${$timeline}[$_] eq $key } 0..$#{$timeline};
+		if ($i > 0) {
+			my $prev_key = ${$timeline}[$i - 1];
+
+			if ($db{$prev_key}->{'global'} == $db{$key}->{'global'}) {
+				$db{$key}->{'start'} = $db{$prev_key}->{'notify'};
+				$re_sort = 1;
+			}
+		}
+
+		if ($i < $#{$timeline}) {
+			my $next_key = ${$timeline}[$i + 1];
+
+			$db{$next_key}->{'start'} = $db{$key}->{'notify'};
 			$re_sort = 1;
-			$db{$next_key}->{'start'} = $notify;
-			$db{$next_key}->{'start'} = $db{$next_key}->{'end'} if $db{$next_key}->{'start'} > $db{$next_key}->{'end'};
-			die if $db{$next_key}->{'start'} > $db{$next_key}->{'end'};
 		}
-		die if $start > $end;
 	}
 }
 
- at sorted_keys = sort sortStart keys %db if $re_sort;
+maybe_sort_keys();
 
 # GPU time accounting
 my (%running, %runnable, %queued, %batch_avg, %batch_total_avg, %batch_count);
-- 
2.14.1