Release the GIL for long-running functions?

[TheRealQuantam]

Would it be possible to release the GIL for long-running functions?

e.g WebPAnimEncoder.add (especially at high quality settings).

[radarhere]

Could you provide some more information? What negative situation are you experiencing that caused you to figure out that Pillow wasn't releasing?

[TheRealQuantam]

The test was really simple: I just spawned 2 threads and had both call save for 2 different WebP Images (though I don't know if it matters, but both were Image.copy's of the same image). It took about 2x as long as a single thread saving 1 image. That and CPU usage never went above 12.5%.

[radarhere]

You may be interested in #7782, which releases the GIL while calling WebPAnimDecoderGetNext