Speed up kernel comparison / loading from cache

Things working:

• !139 (merged)

Things left to do:

• Instructions should not have to be analyzed at all along the fast path from "loading from cache" to "execute".

  • Cache generation of invokers (this is also a non-trivial latency penalty). Invoker generation looks at the instructions and so prevents us from being fully lazy.
  • Kernel.copy() iterates through all instructions; add an option to disable this

• Full use of lazy data structures

  • Add code to generate eq keys and persistent hash keys for instructions (among other things, this has to handle pymbolic expressions, and to normalize the order of sets)
  • Use LazilyUnpicklingList for the list of instructions

cc: @inducer

See also: pytential#38

We decided that a compressed string representation of the kernel could stand in for a comparison key.

I was honestly thinking just the expressions to start...

I was honestly thinking just the expressions to start...

Besides the potential extra effort in making sure the string representation is an isomorphism, why not go the whole way?

changed title from Speed up kernel comparison to Speed up kernel comparison / loading from cache

Besides the potential extra effort in making sure the string representation is an isomorphism, why not go the whole way?

Just that really. If we could make the string representation be valid Python, that would add another bit of utility that would make it worth the effort.

(to me)

!117 (merged) and !118 (closed)

mentioned in issue #80 (closed)

changed the description

mentioned in commit c10458b0

mentioned in merge request !142 (merged)

mentioned in commit c62ff88a

marked the checklist item Kernel.copy() iterates through all instructions; add an option to disable this as completed

mentioned in merge request !144 (merged)

mentioned in commit b47307af

mentioned in merge request !145 (closed)

mentioned in merge request !148 (merged)

marked the checklist item Add code to generate eq keys and persistent hash keys for instructions (among other things, this has to handle pymbolic expressions, and to normalize the order of sets) as completed