I had a look at the code and it is not exactly what I had in mind for the
measurements. The problem with your measurements is that the canvas is
re-drawn only when needed, so the time between two calls to on-paint is not
relevant for performance measurements.
For the on-paint, the time of the draw itself needs to be measured:
(define/override (on-paint)
(define begin-timestamp (current-inexact-milliseconds))
(super on-paint)
(define end-timestamp (current-inexact-milliseconds))
(set! paint-event-stats
(update-statistics paint-event-stats (- end-timestamp begin-
timestamp))))
For the mouse event, the time between when the event is created and the
time it is passed to the callback:
(define ((make-current-value-renderer fn) snip event x y)
(define delta (- (current-inexact-milliseconds) (send event get-time-stamp
)))
(set! mouse-event-stats (update-statistics mouse-event-stats delta))
(define overlays
(and x y (eq? (send event get-event-type) 'motion)
(list (vrule x #:style 'long-dash)
(point-label (vector x (fn x)) #:anchor 'auto))))
(send snip set-overlay-renderers overlays))
Alex.
On Wednesday, June 5, 2019 at 8:06:26 PM UTC+8, evdubs wrote:
>
> Thanks for responding, Alex.
>
> Here's what I came up with <http://pasterack.org/pastes/893> that I think
> satisfies your recommendations. It shows the sin() plot, expects
> interaction for 10 seconds, then prints min/max/mean/std dev for both the
> mouse-event-callback for the snip and on-paint for the editor-canvas%.
>
> Here's the output from running that with Racket 7.2 and Racket 7.3.0.4:
>
> $ ./racket-7.2/bin/racket ~/Code/racket/chart-lag-test.rkt
> Mouse
> Min: 1.115966796875
> Max: 1209.123046875
> Mean: 40.23961775104986
> StdDev: 81.88591520019294
>
> Paint
> Min: 3.35302734375
> Max: 275.579833984375
> Mean: 79.6534423828125
> StdDev: 113.45367443728956
>
> $ ./racket-7.3.0.4/bin/racket ~/Code/racket/chart-lag-test.rkt
> Mouse
> Min: 1.072021484375
> Max: 1095.2412109375
> Mean: 21.93592705160883
> StdDev: 54.53777963909044
>
> Paint
> Min: 3.18798828125
> Max: 284.447998046875
> Mean: 80.8831787109375
> StdDev: 117.90272049413493
>
> These numbers seem to suggest that 7.3 is an improvement, at least from
> the mouse-event stats, even though that is counter to the experience from
> interacting with the plot. Have any other ideas?
>
> Evan
>
> On Tuesday, June 4, 2019 at 1:39:49 PM UTC-10, Alex Harsanyi wrote:
>>
>>
>>
>> On Tuesday, June 4, 2019 at 11:32:42 AM UTC+8, evdubs wrote:
>>>
>>> Thanks for trying it out.
>>>
>>> I just tried using the bash installer from
>>> https://download.racket-lang.org/ and I experience the same issue of
>>> lagginess in 7.3. I also tried using a snapshot release from
>>> https://plt.eecs.northwestern.edu/snapshots/ and I experienced the same
>>> issue.
>>>
>>> I am not sure what I should try next other than maybe profiling, but I
>>> have not had much luck making effective use of the profiler in the past for
>>> interactive applications.
>>>
>>
>> Here are a few things you can try:
>>
>> First, check again whether there’s a performance drop in Racket 7.2 too
>> -- you
>> don’t want to spend time tracking down a Racket problem only to find out
>> that
>> the latest Ubuntu update disabled the hardware acceleration on the
>> graphics
>> card.
>>
>> If it is indeed a regression in Racket 7.3, you can try narrowing the
>> problem
>> down to either rendering or mouse event delays:
>>
>> * you can measure the time it takes to render the plot by measuring the
>> time
>> the paint method of the `editor-canvas%`. You will need to create a
>> custom
>> `editor-canvas%` and override `on-paint` and use
>> `current-inexact-milliseconds` to measure the time.
>>
>> * to check if mouse events are delivered too late to the callback. You
>> can use
>> the `get-time-stamp` method on the event and compare it against
>> `current-inexact-milliseconds` to determine the delay.
>>
>> You will need to compare both values against Racket 7.2 to see which one
>> is
>> causing the slow down.
>>
>> Alex.
>>
>
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