create a "provisional cache" to restore performance in the case of cycles #61754
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It does not, in fact, execute in a recursive context.
I tried to propagate this information with the return value, but I found a curiosity (actually, something that I'm not keen on in general) -- in particular, the candidate cache urrently invokes evaluation, which may detect a cycle, but the "depth" that results from that are is easily propagated back out. This probably means that the candidate caching mechanism *itself* is sort of problematic, but I'm choosing to ignore that in favor of a more ambitious rewrite later.
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So I think I found the bug causing cycle-cache-err-60010.rs to unexpectedly pass -- copy-and-paste error. Working on a fix. UPDATE: Or...not. Not sure what problem is. |
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I think the problem is fixed, not sure what's up with travis |
| /// error. When we pop the node at `reached_depth` from the stack, we | ||
| /// can commit all the things that remain in the provisional cache. | ||
| struct ProvisionalEvaluationCache<'tcx> { | ||
| /// next "depth first number" to issue -- just a counter |
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nit: add (DFN) after "depth first number" as a way of informally binding the acronym in a manner that makes it show up when one does a (case-sensitive) search to find such a binding in the docs.
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(oh I guess it does show up in this "binding" fashion below in the doc for struct ProvisionalEvaluation)
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You might also explicitly state that it is "depth-first number" (and not just "depth") is that this identifies where a node falls in the graph when laid out in depth-first order, right?
(I briefly thought "there must be a standard term for this notion that is less awkward, but I didn't see anything better than "DFS number", which does not seem superior to "DFN")
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DFN is terminology that I took from various prolog papers -- probably this one:
Efficient Top-Down Computation of Queries Under the Well-formed Semantics (Chen, Swift, and Warren; Journal of Logic Programming '95)
so it's not totally unstandard =)
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Actually, I'm not sure why i'm tracking both depth and dfn -- I think you only need the DFN.
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I think I just started with depth and had to add DFN later and didn't realize I could simplify it.
put back negative impls to ensure `Span` is not `Send` nor `Sync`
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none of my feedback is severe enough to block an r+, so I'll go ahead and mark it so. |
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@bors r+ rollup=never |
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📌 Commit bb97fe0 has been approved by |
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Shouldn't this be removed as well? rust/src/libsyntax/tokenstream.rs Lines 52 to 60 in bb97fe0 |
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You'll need |
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Is that a flaky |
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It doesn't look like it should be based on the amount of panics, but I'm not sure. It does use quickcheck which introduces a level of randomness which could lead to it being spurious and/or not related to this PR in particular (cc @BurntSushi as the author). Since I suspect it is unrelated to this PR, let's @bors retry xsv spurious test |
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create a "provisional cache" to restore performance in the case of cycles Introduce a "provisional cache" that caches the results of auto trait resolutions but keeps them from entering the *main* cache until everything is ready. This turned out a bit more complex than I hoped, but I don't see another short term fix -- happy to take suggestions! In the meantime, it's very clear we need to rework the trait solver. This resolves the extreme performance slowdown experienced in #60846 -- I plan to add a perf.rust-lang.org regression test to track this. Caveat: I've not run `x.py test` in full yet. r? @pnkfelix cc @arielb1 Fixes #60846
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☀️ Test successful - checks-travis, status-appveyor |
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Given the number of beta-regressions that we believe were injected by PR #60444 (see #61960), I am beta-nominating this PR. However, I am also a little nervous about back-porting this PR to the current beta, which (if I understand correctly) is scheduled to become the stable release in about two weeks, but his PR itself only landed on nightly 3 days ago. So: Do not immediately assume my nomination is also an endorsement for a backport; I am just trying to initiate discussion of the matter. |
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discussed at T-compiler meeting. Given that this just landed in nightly, we're going to give this a week to bake before officially accepting for beta backport. (But our current inclination is to accept.) |
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@rust-lang/compiler We need to get beta backports approved a little earlier this cycle as we're promoting beta->stable on Saturday. If we could get an FCP going for beta-accepted on this PR that'd be great; or if someone wants to unilaterally beta accept that works too. |
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I'm going to unilaterally beta-accept this. We did talk about the beta-nom of #61754 at the T-compiler meeting last week, and the main misgivings we had were: 1. it didn't seem to resolve all of the performance and overflow issues, 2. it was a bit big+risky for a backport, and 3. it hadn't had much time to bake. But, now it has had time to bake, and (as also stated at the meeting), it fixes a critical issue. So, accepting for beta-backport. |
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…caching-perf-3, r=pnkfelix create a "provisional cache" to restore performance in the case of cycles Introduce a "provisional cache" that caches the results of auto trait resolutions but keeps them from entering the *main* cache until everything is ready. This turned out a bit more complex than I hoped, but I don't see another short term fix -- happy to take suggestions! In the meantime, it's very clear we need to rework the trait solver. This resolves the extreme performance slowdown experienced in rust-lang#60846 -- I plan to add a perf.rust-lang.org regression test to track this. Caveat: I've not run `x.py test` in full yet. r? @pnkfelix cc @arielb1 Fixes rust-lang#60846
[beta] Rollup backports Rolled up: * [beta] Comment out dev key #61700 Cherry picked: * Dont ICE on an attempt to use GAT without feature gate #61118 * Fix cfg(test) build for x86_64-fortanix-unknown-sgx #61503 * Handle index out of bound errors during const eval without panic #61598 * Hygienize macros in the standard library #61629 * Fix ICE involving mut references #61947 * rustc_typeck: correctly compute `Substs` for `Res::SelfCtor`. #61896 * Revert "Set test flag when rustdoc is running with --test option" #61199 * create a "provisional cache" to restore performance in the case of cycles #61754 r? @ghost
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This should have had the beta-nominated flag removed as part of PR #62065, right? |
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Introduce a "provisional cache" that caches the results of auto trait resolutions but keeps them from entering the main cache until everything is ready. This turned out a bit more complex than I hoped, but I don't see another short term fix -- happy to take suggestions! In the meantime, it's very clear we need to rework the trait solver. This resolves the extreme performance slowdown experienced in #60846 -- I plan to add a perf.rust-lang.org regression test to track this.
Caveat: I've not run
x.py testin full yet.r? @pnkfelix
cc @arielb1
Fixes #60846