[igt-dev] [PATCH i-g-t v2 1/9] trace.pl: Improve time axis labels

[John Harrison]

On 7/17/2018 1:56 AM, Tvrtko Ursulin wrote:
>
> On 16/07/2018 18:53, John Harrison wrote:
>> On 7/13/2018 2:55 AM, Tvrtko Ursulin wrote:
>>> From: Tvrtko Ursulin<tvrtko.ursulin at intel.com>
>>>
>>> It is possible to customize the axis display so change it to display
>>> timestamps in seconds on the major axis (with six decimal spaces) and
>>> millisecond offsets on the minor axis.
>>>
>>> v2:
>>>   * Give up on broken relative timestamps.
>>>
>>> Signed-off-by: Tvrtko Ursulin<tvrtko.ursulin at intel.com>
>>> Suggested-by: Chris Wilson<chris at chris-wilson.co.uk>
>>> Cc: Chris Wilson<chris at chris-wilson.co.uk>
>>> Cc: John Harrison<John.C.Harrison at Intel.com>
>>> ---
>>>   scripts/trace.pl | 37 +++++++++++++++++++++++++++++++++++++
>>>   1 file changed, 37 insertions(+)
>>>
>>> diff --git a/scripts/trace.pl b/scripts/trace.pl
>>> index fc1713e4f9a7..41f10749a153 100755
>>> --- a/scripts/trace.pl
>>> +++ b/scripts/trace.pl
>>> @@ -1000,6 +1000,42 @@ $first_ts = ts($first_ts);
>>>   print <<ENDHTML;
>>>     ]);
>>>   +  function majorAxis(date, scale, step) {
>>> +    var s = date / 1000;
>>> +    var precision;
>>> +
>>> +    if (scale == 'millisecond')
>>> +        precision = 6;
>>> +    else if (scale == 'second')
>>> +        precision = 3;
>>> +    else
>>> +        precision = 0;
>>> +
>>> +    return s.toFixed(precision) + "s";
>>> +  }
>>> +
>>> +  function minorAxis(date, scale, step) {
>>> +    var ms = date;
>>> +    var precision;
>>> +    var unit;
>>> +
>>> +    if (scale == 'millisecond') {
>>> +        ms %= 1000;
>>> +        precision = 0;
>>> +        unit = 'ms';
>>> +    } else if (scale == 'second') {
>>> +        ms /= 1000;
>>> +        precision = 1;
>>> +        unit = 's';
>>> +    } else {
>>> +        ms /= 1000;
>>> +        precision = 0;
>>> +        unit = 's';
>>> +    }
>>> +
>>> +    return ms.toFixed(precision) + unit;
>>> +  }
>>> +
>>>     // Configuration for the Timeline
>>>     var options = { groupOrder: 'content',
>>>             horizontalScroll: true,
>>> @@ -1007,6 +1043,7 @@ print <<ENDHTML;
>>>             stackSubgroups: false,
>>>             zoomKey: 'ctrlKey',
>>>             orientation: 'top',
>>> +          format: { majorLabels: majorAxis, minorLabels: minorAxis },
>>>             start: '$first_ts',
>>>             end: '$end_ts'};
>>
>> I'm still seeing some kind of strange offset. However, it appears to 
>> be browser dependent. If I use Chrome then the offset is +28.8 
>> seconds. With Firefox it is -59958115.2 seconds! On the other hand, 
>> if I try Edge or IE then I don't get a graph at all. I'm wondering if 
>> the issue is with Vis browser compatibility rather than anything in 
>> the trace.pl script. Are you seeing anything at all similar?
>>
>> Hmm, if I comment out the 'format:' line and go back to the 
>> unformatted time stamps then IE & Edge still show nothing. However, 
>> Firefox shows dates based on a year of 0097 whereas Chrome says 1997.
>>
>> Either way, I can't spot anything in this patch that could cause a 
>> random offset. So...
>
> Yeah, I can see that now that I tried in Firefox. I was using Chromium 
> so far and there timestamps are exactly matching the ones from the 
> tracepoint log. Which is what we want for easy correlation between the 
> log and HTML..
>
> Firefox corrupts that somehow by applying the large negative offset to 
> everyhting. Perhaps around two year worth of negative seconds if my 
> rough calculation can be trusted. Or Vis under Firefox, I wouldn't 
> know really who is to blame.
>
> I have no idea what to do here. :(
>
> Regards,
>
> Tvrtko

I think ship it for now. It is better than it was. Certainly reporting 
in date format is vaguely meaningless at best and totally meaningless 
with the x1000 scale factor.

Note that chromium on Ubuntu 16.04 does the same as Chrome on Windows 
for me - 28.8 seconds offset. It's not as bad as the 1.9 years of 
Firefox but it is still out :(. I'm guessing it is a bug in the date -> 
absolute seconds conversion going on within either Javascript itself or 
Vis in particular. The timestamps are still encoded as dates in the HTML 
file (and referenced from 0 not from 1900 or 1970 or whatever). So any 
difference in calculating leap years between the Perl script and the 
browser would potentially cause quite a significant delta.

Is it at all possible to put absolute seconds style values in the HTML 
file instead of dates? That would seem like the obvious answer. I don't 
know if Vis would cope with that, though?

John.