Hi all, are we going to have a meeting in 15 minutes?
No, there was no meeting scheduled for today (as far as I know)
That's fine. Shall we make it an async follow-up on current progress? @Zoxc @simulacrum Would you like to give some key points from the data you gathered during past week? Are they positive or negative in general?
Beyond gathering data, I believe we can always discuss about how to accomplish the experiment in following phases. From my recent experience of trying
parallel-rustc, the only convincing way to have two kinds of rustc and compare their performance is to have two copy of rust repo locally and compiled them with
parallel-compiler = true and
parallel-compiler = false respectively. This workflow is too inconvenient to have other users opt-in and do the comparison. Do you have any idea on how to make the experiment user-friendly?
I think for a limited set of platforms (e.g., the ones we currently publish
-alt builds for) we could enable parallel compiler builds on just those
That's linux, macOS, and Windows (64bit).
Unfortunately we currently enable LLVM asserts for those builds so they're slower but potentially we could disable those for the time being? cc @Alex Crichton
We can also publish one-off try builds with the parallel compiler enabled and suggest installation via
I'm not really sure what the context of this is, but the
*-alt builders are currently the builders with llvm assertions enabled
@Alex Crichton ah, I thought that we had some others that ran tests -- I guess we consider bootstrapping "the test" though with -alt
we basically want to ask for community feedback on a parallel-enabled compiler and to do so would wants somewhat regular updates of a parallel compiler build
Our roadmap is to have two experiment phases,
opt-out. In any of them, the users should be able to switch
parallel-rustc on or off. So how can we make it? In detail , during the first phase, what is the default behavior of the rustc? Is it a compiler with
parallel-compiler = false? Or
parallel-compiler = true & -Zthreads=1? As far as I know, the later one is what we can provide technically. While the first one is what we should have for comparison, so that we can measure the overhead added by
parallel-rustc. This is the contradiction that troubles me .