This author also has other things like: A compiler that emits only `mov` instructions and another compiler that deliberately messes with the control flow so that, if disassembled, common debuggers will draw symbols like skulls or threats. https://github.com/xoreaxeaxeax/repsych
It'd be really interesting to see whether the winning (losing?) instructions/strategies would be different on other architectures. At least right now the top spot (`fxrstor64` on MMIO, starve PCIe) seems relatively architecture-independent, but maybe something about MMIO ordering rules on e.g. POWER would be different enough to change that -- or perhaps open up new avenues?
I wonder what the actual limit on this `fxrstor64` is right now. If you can stall the PCIe bus for that long, then why not indefinitely? Certainly there's no forward progress guarantee here.
There’s definitely strategies here; A lot of the floating point operations use subnormals, and a lot of the worst instructions are slowed down by really, really fucking with MMIO.
This author also has other things like: A compiler that emits only `mov` instructions and another compiler that deliberately messes with the control flow so that, if disassembled, common debuggers will draw symbols like skulls or threats. https://github.com/xoreaxeaxeax/repsych
what im seeing from this chart is that we should be using the nop instruction for everything
Well the best code is no code. Nop could be second best though.
A great resource for any performance deoptimization.
It'd be really interesting to see whether the winning (losing?) instructions/strategies would be different on other architectures. At least right now the top spot (`fxrstor64` on MMIO, starve PCIe) seems relatively architecture-independent, but maybe something about MMIO ordering rules on e.g. POWER would be different enough to change that -- or perhaps open up new avenues?
I wonder what the actual limit on this `fxrstor64` is right now. If you can stall the PCIe bus for that long, then why not indefinitely? Certainly there's no forward progress guarantee here.
There’s definitely strategies here; A lot of the floating point operations use subnormals, and a lot of the worst instructions are slowed down by really, really fucking with MMIO.
It’s crazy how computers still seem to get perceivably slow every few years, given how many instructions can be executed in 1ms. Shameful, even..
What’s that law called about programmers wasting all the compute on abstraction?
The new windows notepad is a disgrace
Huh? A millisecond is an eternity!