Re: How to measure frame rate in fps?

[Arthur Miller <arthur.miller@live.com>]

Jimmy Yuen Ho Wong <wyuenho@gmail.com> writes:

> Hi everyone,
>
> I've gotten into a discussion with isort's author about how fast
> editors can actually render text.

FPS is not necessary the measure of how fast you can render text. Sure
it directly affects fps, but fps is more complex than just how fast text
is rendered. It is also affected by how fast your hardware and OS can
swap frames, how your OS multitasks processes etc. When you read
benchmarks at sites like Tomshardware, notice that they use different
games and applications to measure the performance. They really are
concerned with how the underlaying hardware and OS perform in that
particular game and application. Different games will result with
different number of FPS. So FPS is just a relative measure for the
application at hand.

How fast text can be rendered on any computer depends on the hardware of
course and how efficiently code used to render text use that
hardware. Most "normal" applications like text processors will use
whatever the OS provides. I guess you have to ask Mr. Eliz & Co for the
details about how Emacs renders text, or look at the source.

Anyway, you could create small app to some teoretical speed of how much
text you could render on your own computer with your choice of the
library. "Theoretical" because it is really difficult to get 
reliable measure when it comes to just rendering speed on modern
computers since cpus run at variable speed to save the energy, OSs are
scheduling processes and stuff at they will, data has to be send over
the bus to gpu if there is one, and so on. 

For the Emacs I don't think you can get a meaningful measure "out of the
box" since Emacs run in a blocking event qeue, which means Emacs does
nothing unless there is input. Maybe you could construct a test and
render a considerably big piece of text in an empty buffer and take the
time, repeat several times and take mean time, to give you some feel of
howa fast it happends, but I am not sure how reliably you could do this
in Emacs.

I don't think it matters much either. Most CPUs can render "enough" text,
fast enough that it really isn't important. What does it matter if one
can render 10 billion characters at 144 fps, if one can display only few
hundreds or max few thousands at the time on the screen? Who
cares. Consider a Ferrari vs a Volvo. Sure, Ferrari is faster, but Volvo
will do the jobb 99% of the time for 99% of the people.