Optimize try_mark_green and eliminate the lock on dep node colors #57065
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@bors try |
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⌛ Trying commit 84aa34d621f10826957bb64c08699307a3f69fc3 with merge 2897f68c5b419b38ac5e1a32910abe9112ea8a3c... |
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☀️ Test successful - status-travis |
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Nice @rust-timer build 2897f68c5b419b38ac5e1a32910abe9112ea8a3c |
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@rust-timer build 2897f68c5b419b38ac5e1a32910abe9112ea8a3c |
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Success: Queued 2897f68c5b419b38ac5e1a32910abe9112ea8a3c with parent fa922ab, comparison URL. |
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Finished benchmarking try commit 2897f68c5b419b38ac5e1a32910abe9112ea8a3c |
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This is another case where measuring with parallel queries would be useful... |
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@michaelwoerister Benchmarks on x86 won't be useful, since the atomic operations lowers to regular load/stores, so this literally just removes the lock on dep node colors. |
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I know but that lock can only be really expensive with parallel queries because of contention, right? |
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☔ The latest upstream changes (presumably #57607) made this pull request unmergeable. Please resolve the merge conflicts. |
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It would have been nice to have a performance comparison for the multi-threaded case but that's complicated and not really worth the effort. The changes already show a small win in single-threaded mode and it can only improve the situation with parallel queries, so let's go ahead and merge.
r=me with the nits addressed.
Great work, @Zoxc!
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| debug_assert!(data.colors.borrow().get(prev_dep_node_index).is_none()); | ||
| fn try_mark_previous_green<'tcx>( |
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Could you add a doc comment here? Something like "Try to mark a dep-node green for which we already know that it existed in the previous compilation session".
src/librustc/dep_graph/graph.rs
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| // We never try to mark inputs as green | ||
| // FIXME: Make an debug_assert! | ||
| assert!(!dep_node.kind.is_input()); |
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We already do the debug assertion a few lines above. You can just remove this one (and move the comment up).
src/librustc/dep_graph/graph.rs
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| // This DepNode and the corresponding query invocation existed | ||
| // in the previous compilation session too, so we can try to | ||
| // mark it as green by recursively marking all of its | ||
| // dependencies green. |
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Could you move this comment into the None branch of the match below?
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@bors r=michaelwoerister |
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📌 Commit 1313678 has been approved by |
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Optimize try_mark_green and eliminate the lock on dep node colors Blocked on rust-lang#56614 r? @michaelwoerister
Rollup of 6 pull requests Successful merges: - #56884 (rustdoc: overhaul code block lexing errors) - #57065 (Optimize try_mark_green and eliminate the lock on dep node colors) - #57107 (Add a regression test for mutating a non-mut #[thread_local]) - #57268 (Add a target option "merge-functions", and a corresponding -Z flag (works around #57356)) - #57551 (resolve: Add a test for issue #57539) - #57598 (Add missing unpretty option help message) Failed merges: r? @ghost
Optimize try_mark_green and eliminate the lock on dep node colors Blocked on rust-lang#56614 r? @michaelwoerister
Optimize try_mark_green and eliminate the lock on dep node colors Blocked on rust-lang#56614 r? @michaelwoerister
Optimize try_mark_green and eliminate the lock on dep node colors Blocked on rust-lang#56614 r? @michaelwoerister
Optimize try_mark_green and eliminate the lock on dep node colors Blocked on #56614 r? @michaelwoerister
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☀️ Test successful - checks-travis, status-appveyor |
Blocked on #56614
r? @michaelwoerister