tree 8c6d055c551f9468e534f306882b17523b992e1a
parent 961d4dc80a8a6cde7210fb2bbd7d1c091a0092ff
author Matthias Boehm <mboehm7@gmail.com> 1597772836 +0200
committer Matthias Boehm <mboehm7@gmail.com> 1597772837 +0200

[SYSTEMDS-2600,2626] Fix federated backend request interference

This patch fixes two major issues of request interference from multiple
coordinator threads.

First, we now properly maintain separate execution context at the
federated site for different request streams from parfor workers which
otherwise could interfer (e.g., on rmvar instructions for shared input
variables)

Second, even within a stream of federated requests (e.g., execute and
cleanup) could out output each other if there are no data dependencies
or synchronization between them. We now added barriers for federated
requests wherever this was necessary.

Last, this patch also fixes unnecessary warning messages of the parfor
optimizer, specifically in a setting with forced singlenode execution.

Closes #1028.