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johannesvollmer / exrs

100% Safe Rust OpenEXR file library
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how to use the library with maximum performance #209

Open johannesvollmer opened 1 year ago

johannesvollmer commented 1 year ago

What can be improved or is missing?

the documentation should provide the basic steps necessary to obtain the best performance. for example, setting the target cpu to native in .cargo/config.toml. But also LTO. feature flags in dependencies, like half: use-intrinsics. and which exr variants are faster and whatnot.

Shnatsel commented 1 year ago

We should also back that up with benchmarks. I doubt LTO is going to be much of a gain. -C codegen-units=1 is also worth a shot. And if -Ctarget-cpu=native does indeed help, we should just identify the functions that get a speedup and multiversion them using the multiversion crate - that way the speedups will be accessible to everyone without the need to use -Ctarget-cpu=native.

johannesvollmer commented 1 year ago

great ideas :)

Shnatsel commented 1 year ago

The latest version of half crate now uses the f16 conversion intrinsics on stable Rust, so reading to f16 will be a lot faster on half v2.3.1 and later.

johannesvollmer commented 1 year ago

awesome, does that mean we can finally continue that pull request from some time ago? :) #191