ECDSA example runs slower than expected?

[matthiasgeihs]

I've been running the ECDSA example on an M1 Pro (10/16 cores) with Metal enabled (cargo run --release --features=risc0-zkvm/metal) at latest commit (83cf686).

The README suggests that this should take about 17s. However, I'm measuring a prover running time of about 52s. Where is that difference coming from?

[pdg744]

This performance hit was caused by the v0.20 release and addressed in the v0.20.1 release.