Re: How to measure frame rate in fps?

[Dmitry Gutov]

On 01.06.2021 14:43, Eli Zaretskii wrote:
> You just need to remember to include some command that
> would affect the display, or else redisplay will do very little and
> redraw nothing.

Speaking of redisplay redrawing nothing, as long as tool-bar-mode is on, 
my GTK3 build (with -Q even) evaluates (benchmark 1 '(redisplay)) to a 
sequence of results like this:

Elapsed time: 0.040924s
Elapsed time: 0.026343s
Elapsed time: 0.023473s
Elapsed time: 0.025162s
Elapsed time: 0.030074s
Elapsed time: 0.041305s (0.026917s in 1 GCs)
Elapsed time: 0.031169s
Elapsed time: 0.020957s
Elapsed time: 0.034885s
Elapsed time: 0.035338s
Elapsed time: 0.030864s

and with tool-bar-mode off:

Elapsed time: 0.007189s
Elapsed time: 0.006181s
Elapsed time: 0.007358s
Elapsed time: 0.004177s
Elapsed time: 0.007754s
Elapsed time: 0.007557s

Not so noticeable if it just happens once, but easily affects the 
performance of code which performs "virtual" redisplay, such as 
posn-at-point.

Sometimes the effect disappears (even with tool-bar-mode on), but to 
bring it back I only had to call (redisplay t) once.