Re: [ft-devel] "Inside the fastest font renderer in the world"

[Alexei Podtelezhnikov]

On Thu, Aug 4, 2016 at 4:23 PM, Behdad Esfahbod <address@hidden> wrote:

>> Conceptually, are we into parallelizing Freetype rendering engine? As
>> I alluded earlier this can be happily delegated to text layout
>> engines. Hence we used to care about thread safety in Freetype, while
>> the text layout engine is busy processing 8 letters at once. Raph uses
>> at least 8-core processor. I would be interested to see how his
>> renderer performs on a single core, without parallel tricks.
>
> You are seriously misunderstanding what font-rs is doing.  It's using
> SIMD instructions [0].  That's still one core.  And, he's also showing
> 6x speedup without SIMD.  Really, it's just plain honest tight piece
> of code.  No magic involved.

Alright. Last time somebody has done actual profiling [1], it was
arithmetic of calculating coverages that took all the time,
specifically divisions. Is that the problem solved by font-rs? You do
not even need 'g' to stress-test rendering: a slanted line or a '/'
would do. I do not understand how 6x is even possible. I wish the
paper analyzed weaknesses of Freetype in more details.

[1] http://lists.nongnu.org/archive/html/freetype-devel/2015-10/msg00027.html