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aebd84b525
The previous logic was made really messy by the fact that upon entry to the step eval worker, the step may not be ready to run, we may be racing with other workers doing the same check, and we had already acquired our RSS requirement even though we might not run. It also required iterating all dependencies each time we were called to check whether we were even ready to run yet. A much better strategy is for each step to have an atomic counter representing how many of its dependencies are yet to complete. When a step completes (successfully or otherwise), it decrements this value for all of its dependants, and if it drops any to 0, it schedules that step to run. This means each step is scheduled exactly once, and only when all of its dependencies have finished, reducing redundant checks and hence contention. If the step being scheduled needs to claim RSS which isn't available, then it is instead added to `memory_blocked_steps`, which is iterated by the step worker after a step with an RSS claim finishes. This logic is more concise than before, simpler to understand, generally more efficient, and fixes a bug in the RSS tracking. Also, as a nice side effect, it should also play a little bit nicer with `Io.Threaded`'s scheduling strategy, because we no longer spawn extremely short-lived tasks all the time as we previously did. Resolves: https://codeberg.org/ziglang/zig/issues/30742 |
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| FsEvents.zig | ||