Problem:

Users may see slower upload speeds when transferring files to S3 on AWS in a job using a macOS M1 executor. This is likely due to an issue with the Apple virtualization framework on macOS M1 instances.

Solutions:

• Disable TSO (TCP segmentation offload)

  • To disable TSO, please add the following run step in your job before any steps interacting with S3:
    - run: sudo sysctl net.inet.tcp.tso=0

Outcome:

After disabling TSO, users can likely see improved transfer speeds.
However, please note that disabling TSO can increase CPU overhead for TCP/IP operations.
This solution may cause overall job slowness for jobs that are network-heavy.