relax assertion involving pg->nold to reflect that it may be a bit in… #50466
Conversation
d-netto
added
GC
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If we're fine with losing a bit of precision due to data races we can probably relax the atomic here to separate loads and stores. |
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What I'm saying is that we can still use that information to skip a sweep even when multithreaded, so the mark_threads == 0 should only potentially guard the assertion. |
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I believe this could lead us to incorrectly skip the page. As an example, we may have a case where the racy increment would cause nold to be exactly prev_nold, while a non-racy update would lead nold to be less than prev_nold. In this case, the racy update will lead us to take an incorrect sweeping decision. |
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Fair enough, LGTM |
oscardssmith
removed
the
merge me
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I guess we might sweep more than necessary in this case then, which is fine, but still less than with this pr where we always sweep? |
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I believe this would be incorrect since a race on setting the mark-bits in Two threads may end up marking the same object twice, but actually calling |
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Ah, right, you might have still needed |
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This causes quite a big regression in some cases. So it seems it's not worth it . |
Backported PRs: - [x] #50411 <!-- Fix weird dispatch of * with zero arguments --> - [x] #50202 <!-- Remove dynamic dispatch from _wait/wait2 --> - [x] #50064 <!-- Fix numbered prompt with input only with comment --> - [x] #50026 <!-- Store heapsnapshot files in tempdir() instead of current directory --> - [x] #50402 <!-- Add CPU feature helper function --> - [x] #50387 <!-- update newpages pointer after actually sweeping pages --> - [x] #50424 <!-- avoid potential type-instability in _replace_(str, ...) --> - [x] #50444 <!-- Optimize getfield lowering to avoid boxing in some cases --> - [x] #50474 <!-- docs: Fix a `!!! note` which was miscapitalized --> - [x] #50466 <!-- relax assertion involving pg->nold to reflect that it may be a bit in… --> - [x] #50490 <!-- Fix compat annotation for italic printstyled --> - [x] #50488 <!-- fix typo in `Base.isassigned` with `Tridiagonal` --> - [x] #50476 <!-- Profile: Add specifying dir for `take_heap_snapshot` and handling if current dir is unwritable --> - [x] #50461 <!-- fix typo in the --gcthreads argument description --> - [x] #50528 <!-- ssair: Correctly handle stmt insertion at end of basic block --> - [x] #50533 <!-- ensure internal_obj_base_ptr checks whether objects past freelist pointer are in freelist --> - [x] #49322 <!-- improve cat design / performance --> - [x] #50540 <!-- gc: remove over-eager assertion --> - [x] #50542 <!-- gf: remove unnecessary assert cycle==depth --> - [x] #50559 <!-- Expand kwcall lowering positional default check to vararg --> - [x] #50058 <!-- Add unwrapping mechanism for triangular mul and solves --> - [x] #50551 <!-- typeintersect: also record chained `innervars` --> - [x] #50552 <!-- read(io, Char): fix read with too many leading ones --> - [x] #50541 <!-- precompile: ensure globals are not accidentally created where disallowed --> - [x] #50576 <!-- use atomic compare exchange when setting the GC mark-bit --> - [x] #50578 <!-- gf: make method overwrite/delete an error during precompile --> - [x] #50516 <!-- Fix visibility of assert on GCC12/13 --> - [x] #50597 <!-- Fix memory corruption if task is launched inside finalizer --> - [x] #50591 <!-- build: fix various makefile bugs --> - [x] #50599 <!-- faster invalid object lookup in conservative gc --> - [x] #50634 <!-- 🤖 [master] Bump the SparseArrays stdlib from b4b0e72 to 99c99b4 --> - [x] #50639 <!-- Backport LLVM patches to fix various issues. --> - [x] #50546 <!-- Revert storage of method instance in LineInfoNode --> - [x] #50631 <!-- Shift DCE pass to optimize imaging mode code better --> - [x] #50525 <!-- only check that values are finite in `generic_lufact` when `check=true` --> - [x] #50587 <!-- isassigned for ranges with BigInt indices --> - [x] #50144 <!-- Page based heap size heuristics --> Need manual backport: - [ ] #50595 <!-- Rename ENV variable `JULIA_USE_NEW_PARSER` -> `JULIA_USE_FLISP_PARSER` --> Non-merged PRs with backport label: - [ ] #50637 <!-- Remove SparseArrays legacy code --> - [ ] #50618 <!-- inference: continue const-prop' when concrete-eval returns non-inlineable --> - [ ] #50598 <!-- only limit types in stack traces in the REPL --> - [ ] #50594 <!-- Disallow non-index Integer types in isassigned --> - [ ] #50568 <!-- `Array(::AbstractRange)` should return an `Array` --> - [ ] #50523 <!-- Avoid generic call in most cases for getproperty --> - [ ] #50172 <!-- print feature flags used for matching pkgimage -->
KristofferC
removed
the
backport 1.10
…accurate with parallel marking
Should fix #50419.