Fix gpu cancel issue

[n13]

Problem

Canceling GPU would have to wait out the entire GPU batch range

This would also block all CPU threads

Solution

• Canceling GPU asynchronously
• GPU batch size adjusts to optional GPU time, default 3 seconds

Future improvements

• Clean up logs - they all need targets and most of them should be debug
• See if we can initialize GPU more efficiently - we lose a lot compared to the benchmarks