On 10/05/2019 13:33, Chris Wilson wrote:
Quoting Tvrtko Ursulin (2019-05-08 13:10:38)
From: Tvrtko Ursulin <tvrtko.ursu...@intel.com>

After the removal of engine global seqnos and the corresponding
intel_engine_notify tracepoints the script needs to be adjusted to cope
with the new state of things.

To keep working it switches over using the dma_fence:dma_fence_signaled:
tracepoint and keeps one extra internal map to connect the ctx-seqno pairs
with engines.

It also needs to key the completion events on the full engine/ctx/seqno
tokens, and adjust correspondingly the timeline sorting logic.

v2:
  * Do not use late notifications (received after context complete) when
    splitting up coalesced requests. They are now much more likely and can
    not be used.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursu...@intel.com>
---
  scripts/trace.pl | 82 ++++++++++++++++++++++++------------------------
  1 file changed, 41 insertions(+), 41 deletions(-)

diff --git a/scripts/trace.pl b/scripts/trace.pl
index 18f9f3b18396..95dc3a645e8e 100755
--- a/scripts/trace.pl
+++ b/scripts/trace.pl
@@ -27,7 +27,8 @@ use warnings;
  use 5.010;
my $gid = 0;
-my (%db, %queue, %submit, %notify, %rings, %ctxdb, %ringmap, %reqwait, 
%ctxtimelines);
+my (%db, %queue, %submit, %notify, %rings, %ctxdb, %ringmap, %reqwait,
+    %ctxtimelines, %ctxengines);
  my @freqs;

So what's ctxengines? Or rings for that matter?

rings go back to the beginnings of the tool when I think the visualizaiton library needed an unique integer value for every timeline (so engine). And there is a ringmap from this id back to our engine name. Perhaps this would be clearer if reversed, but I am not sure how much churn would that be without actually doing it. Renaming rings to engines would also make sense.

I take it ctxengines is really the last engine which we saw this context
execute on?

Correct.

I guess there is a problem if dma_fence_signaled is delayed past another request_in. Hm but I also have a die if engine is different.. that cannot be right, but why it didn't fail.. I need to double check this.


my $max_items = 3000;
@@ -66,7 +67,7 @@ Notes:
                                i915:i915_request_submit, \
                                i915:i915_request_in, \
                                i915:i915_request_out, \
-                              i915:intel_engine_notify, \
+                              dma_fence:dma_fence_signaled, \
                                i915:i915_request_wait_begin, \
                                i915:i915_request_wait_end \
                                [command-to-be-profiled]
@@ -161,7 +162,7 @@ sub arg_trace
                        'i915:i915_request_submit',
                        'i915:i915_request_in',
                        'i915:i915_request_out',
-                      'i915:intel_engine_notify',
+                      'dma_fence:dma_fence_signaled',
                        'i915:i915_request_wait_begin',
                        'i915:i915_request_wait_end' );
@@ -312,13 +313,6 @@ sub db_key
         return $ring . '/' . $ctx . '/' . $seqno;
  }
-sub global_key
-{
-       my ($ring, $seqno) = @_;
-
-       return $ring . '/' . $seqno;
-}
-
  sub sanitize_ctx
  {
         my ($ctx, $ring) = @_;
@@ -419,6 +413,8 @@ while (<>) {
                 $req{'ring'} = $ring;
                 $req{'seqno'} = $seqno;
                 $req{'ctx'} = $ctx;
+               die if exists $ctxengines{$ctx} and $ctxengines{$ctx} ne $ring;
+               $ctxengines{$ctx} = $ring;
                 $ctxtimelines{$ctx . '/' . $ring} = 1;
                 $req{'name'} = $ctx . '/' . $seqno;
                 $req{'global'} = $tp{'global'};
@@ -429,16 +425,29 @@ while (<>) {
                 $ringmap{$rings{$ring}} = $ring;
                 $db{$key} = \%req;
         } elsif ($tp_name eq 'i915:i915_request_out:') {
-               my $gkey = global_key($ring, $tp{'global'});
+               my $gkey;
+

# Must be paired with a previous i915_request_in
+               die unless exists $ctxengines{$ctx};

I'd suggest next unless, because there's always a change the capture is
started part way though someone's workload.

That would need much more work.


+               $gkey = db_key($ctxengines{$ctx}, $ctx, $seqno);
+
+               if ($tp{'completed?'}) {
+                       die unless exists $db{$key};
+                       die unless exists $db{$key}->{'start'};
+                       die if exists $db{$key}->{'end'};
+
+                       $db{$key}->{'end'} = $time;
+                       $db{$key}->{'notify'} = $notify{$gkey}
+                                               if exists $notify{$gkey};

Hmm. With preempt-to-busy, a request can complete when we are no longer
tracking it (it completes before we preempt it).

They will still get the schedule-out tracepoint, but marked as
incomplete, and there will be a signaled tp later before we try and
resubmit.

This sounds like the request would disappear from the scripts view.


+               } else {
+                       delete $db{$key};
+               }
+       } elsif ($tp_name eq 'dma_fence:dma_fence_signaled:') {
+               my $gkey;
- die unless exists $db{$key};
-               die unless exists $db{$key}->{'start'};
-               die if exists $db{$key}->{'end'};
+               die unless exists $ctxengines{$tp{'context'}};
- $db{$key}->{'end'} = $time;
-               $db{$key}->{'notify'} = $notify{$gkey} if exists $notify{$gkey};
-       } elsif ($tp_name eq 'i915:intel_engine_notify:') {
-               my $gkey = global_key($ring, $seqno);
+               $gkey = db_key($ctxengines{$tp{'context'}}, $tp{'context'}, 
$tp{'seqno'});
$notify{$gkey} = $time unless exists $notify{$gkey};
         } elsif ($tp_name eq 'i915:intel_gpu_freq_change:') {
@@ -452,7 +461,7 @@ while (<>) {
  # find the largest seqno to be used for timeline sorting purposes.
  my $max_seqno = 0;
  foreach my $key (keys %db) {
-       my $gkey = global_key($db{$key}->{'ring'}, $db{$key}->{'global'});
+       my $gkey = db_key($db{$key}->{'ring'}, $db{$key}->{'ctx'}, 
$db{$key}->{'seqno'});
die unless exists $db{$key}->{'start'}; @@ -478,14 +487,13 @@ my $key_count = scalar(keys %db); my %engine_timelines; -sub sortEngine {
-       my $as = $db{$a}->{'global'};
-       my $bs = $db{$b}->{'global'};
+sub sortStart {
+       my $as = $db{$a}->{'start'};
+       my $bs = $db{$b}->{'start'};
         my $val;
$val = $as <=> $bs;
-
-       die if $val == 0;
+       $val = $a cmp $b if $val == 0;
return $val;
  }
@@ -497,9 +505,7 @@ sub get_engine_timeline {
         return $engine_timelines{$ring} if exists $engine_timelines{$ring};
@timeline = grep { $db{$_}->{'ring'} eq $ring } keys %db;
-       # FIXME seqno restart
-       @timeline = sort sortEngine @timeline;
-
+       @timeline = sort sortStart @timeline;
         $engine_timelines{$ring} = \@timeline;
return \@timeline;
@@ -561,20 +567,10 @@ foreach my $gid (sort keys %rings) {
                         $db{$key}->{'no-notify'} = 1;
                 }
                 $db{$key}->{'end'} = $end;
+               $db{$key}->{'notify'} = $end if $db{$key}->{'notify'} > $end;
         }
  }
-sub sortStart {
-       my $as = $db{$a}->{'start'};
-       my $bs = $db{$b}->{'start'};
-       my $val;
-
-       $val = $as <=> $bs;
-       $val = $a cmp $b if $val == 0;
-
-       return $val;
-}
-
  my $re_sort = 1;
  my @sorted_keys;
@@ -670,9 +666,13 @@ if ($correct_durations) {
                         next unless exists $db{$key}->{'no-end'};
                         last if $pos == $#{$timeline};
- # Shift following request to start after the current one
+                       # Shift following request to start after the current
+                       # one, but only if that wouldn't make it zero duration,
+                       # which would indicate notify arrived after context
+                       # complete.
                         $next_key = ${$timeline}[$pos + 1];
-                       if (exists $db{$key}->{'notify'}) {
+                       if (exists $db{$key}->{'notify'} and
+                           $db{$key}->{'notify'} < $db{$key}->{'end'}) {
                                 $db{$next_key}->{'engine-start'} = 
$db{$next_key}->{'start'};
                                 $db{$next_key}->{'start'} = 
$db{$key}->{'notify'};
                                 $re_sort = 1;
@@ -750,9 +750,9 @@ foreach my $gid (sort keys %rings) {
         # Extract all GPU busy intervals and sort them.
         foreach my $key (@sorted_keys) {
                 next unless $db{$key}->{'ring'} eq $ring;
+               die if $db{$key}->{'start'} > $db{$key}->{'end'};

Heh, we're out of luck if we want to trace across seqno wraparound.

Yeah, that's another missing thing.


It makes enough sense,
Reviewed-by: Chris Wilson <ch...@chris-wilson.co.uk>

Thanks. Overall the script could use a cleanup so I'll try to find some time towards it when this settles.

Regards,

Tvrtko


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