fixed point was a mistake

[muri@troet.cafe]

@eniko what a rollercoaster of emotions!

[gabrielesvelto@mas.to]

@ratsnakegames @eniko

[gabrielesvelto@mas.to]

@ratsnakegames @eniko I wanted to write COBOL not FORTRAN but my brain missed a beat

[ratsnakegames@mastodon.social]

@gabrielesvelto @eniko we still do that sh*t in Java or .NET these days because financial regulators really frown upon money vanishing because of floating point errors

[gabrielesvelto@mas.to]

@ratsnakegames and I commend you for that! In a past life I worked for a high-frquency trading firm and their software did financial calculations using floating point numbers 🤷

[gabrielesvelto@mas.to]

@eniko jumpscare

[m3t00@app.wafrn.net]

when 64kb ram was all anyone would ever need

[sabik@rants.au]

@gabrielesvelto @ratsnakegames
Eh, as long as there's enough bits in the mantissa...

[kevingranade@mastodon.gamedev.place]

@eniko following with interest.

[eniko@mastodon.gamedev.place]

I have completed the triangle rasterizer fixed point conversion

The benchmarks have all improved between 0 and 35%

Except for threaded random triangles with flat color. That metric has increased 106%. As in its twice as fast as before

I have no idea why but I'm fairly sure I've ruled out bugs in my benchmarking

I am very confused

[atridas@mastodon.gamedev.place]

@eniko fixed point is very fun

[lina@vt.social]

@eniko Hyperthreading? That has very different behavior depending on the kind of code being run. A single core might have twice the int resources to handle two threads of throughput but not twice the float resources (and then it depends on how bottlenecked by things like memory latency the benchmark is).

[eniko@mastodon.gamedev.place]

@lina I don't know? >_> I just split the screen between 4 worker threads that all draw each triangle to their quadrant

[lina@vt.social]

@eniko How many cores/threads does your machine have? Can you pin app threads to specific cores/threads?

[natty@astolfo.social]

@eniko@mastodon.gamedev.place @lina@vt.social do you happen to own a Bulldozer CPU? ​​

[eniko@mastodon.gamedev.place]

@lina not sure offhand and I'm in bed now but my CPU is a Ryzen 7 5600g

[eniko@mastodon.gamedev.place]

@natty @lina my CPU is a Ryzen 5 5600g?

[slyecho@mdon.ee]

@eniko mutex/locking/semaphores?

[snowfox@tech.lgbt]

@eniko (Highly speculative, since FPUs are pretty good these days:) If the CPU has hyperthreading: Maybe two fixed-point threads share ALUs better than two floating-point threads share FPUs?

You might even find that combined fixed and float makes better overall use of a modern CPU, provided you can do both on a single thread or jump through the hoops to get both threads scheduled on the same core.

[lina@vt.social]

@eniko That doesn't exist... Ryzen 5 or different model number?

If it's the 5 5600G then that's 6 cores, so with 4 threads you shouldn't have HT effects as long as the OS scheduler isn't dumb about it...