Can't run two concurrent asv jobs in same directory

[astrofrog]

I tried doing this, but all concurrent jobs try and build the project in the same env sub-directory

[pv]

The only way to do this would be to use different environments for the different runs, as the project also needs to be installed in the env.

[astrofrog]

I wonder if we could add a flag that means 'randomize the environment ID for this run' or something similar.

[pv]

Probably better would be to use a different env_dir for the different parallel runs.
Also probably needs some locking in producing the output files etc.

[pv]

For example, if some magic is ok here, using env/1/a9747819ec1127665def08a36932eab6 as a fallback if it is determined that env/a9747819ec1127665def08a36932eab6 is locked by a different asv process.

[mdboom]

I think it's going to be pretty hard to do this kind of parallelism from the outside, since we can't control how it's done. There is some support for parallel environment building, however. I guess I need a better sense of the use case here.