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Make intern_lazy_const actually intern its argument. #58207

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merged 1 commit into from
Feb 9, 2019
Merged

Make intern_lazy_const actually intern its argument. #58207

merged 1 commit into from
Feb 9, 2019

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nnethercote
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Currently it just unconditionally allocates it in the arena.

For a "Clean Check" build of the the packed-simd benchmark, this
change reduces both the max-rss and faults counts by 59%; it
slightly (~3%) increases the instruction counts but the wall-time is
unchanged.

For the same builds of a few other benchmarks, max-rss and faults
drop by 1--5%, but instruction counts and wall-time changes are in the
noise.

Fixes #57432, fixes #57829.

@nnethercote
Make intern_lazy_const actually intern its argument.
f2871a9 
Currently it just unconditionally allocates it in the arena.

For a "Clean Check" build of the the `packed-simd` benchmark, this
change reduces both the `max-rss` and `faults` counts by 59%; it
slightly (~3%) increases the instruction counts but the `wall-time` is
unchanged.

For the same builds of a few other benchmarks, `max-rss` and `faults`
drop by 1--5%, but instruction counts and `wall-time` changes are in the
noise.

Fixes rust-lang#57432, fixes rust-lang#57829.
@rust-highfive
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r? @petrochenkov

(rust_highfive has picked a reviewer for you, use r? to override)

@rust-highfive rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Feb 6, 2019
@nnethercote
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I'm no expert on interning but this appears to do the trick.

r? @oli-obk

cc @RalfJung

@rust-highfive rust-highfive assigned oli-obk and unassigned petrochenkov Feb 6, 2019
@nnethercote
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@bors try

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bors commented Feb 6, 2019

⌛ Trying commit f2871a9 with merge 75a5b718ee128eee283eb50bc379c66401add1e5...

@Zoxc
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Zoxc commented Feb 6, 2019

I find it amusing that this removes intern from the name, but actually adds interning.

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bors commented Feb 6, 2019

☀️ Test successful - checks-travis
State: approved= try=True

@nnethercote
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@rust-timer build 75a5b718ee128eee283eb50bc379c66401add1e5

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Success: Queued 75a5b718ee128eee283eb50bc379c66401add1e5 with parent 65e647c, comparison URL.

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Finished benchmarking try commit 75a5b718ee128eee283eb50bc379c66401add1e5

@nnethercote
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Perf results are very similar to what I saw locally: big max-rss and faults wins, minor instruction count increases, but no obvious corresponding wall-time increases.

@oli-obk
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oli-obk commented Feb 6, 2019

@bors r+

awesome!

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bors commented Feb 6, 2019

📌 Commit f2871a9 has been approved by oli-obk

@bors bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Feb 6, 2019
@RalfJung
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RalfJung commented Feb 9, 2019

Given the impact of the regression this fixes, is it appropriate to give it higher priority?

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@bors p=1

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bors commented Feb 9, 2019

⌛ Testing commit f2871a9 with merge d329d46...

bors added a commit that referenced this pull request Feb 9, 2019
@bors
Auto merge of #58207 - nnethercote:intern_lazy_const, r=oli-obk
d329d46 
Make `intern_lazy_const` actually intern its argument.

Currently it just unconditionally allocates it in the arena.

For a "Clean Check" build of the the `packed-simd` benchmark, this
change reduces both the `max-rss` and `faults` counts by 59%; it
slightly (~3%) increases the instruction counts but the `wall-time` is
unchanged.

For the same builds of a few other benchmarks, `max-rss` and `faults`
drop by 1--5%, but instruction counts and `wall-time` changes are in the
noise.

Fixes #57432, fixes #57829.
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bors commented Feb 9, 2019

☀️ Test successful - checks-travis, status-appveyor
Approved by: oli-obk
Pushing d329d46 to master...

@bors bors added the merged-by-bors This PR was explicitly merged by bors. label Feb 9, 2019
@bors bors merged commit f2871a9 into rust-lang:master Feb 9, 2019
@bors bors mentioned this pull request Feb 9, 2019
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@nnethercote nnethercote deleted the intern_lazy_const branch February 11, 2019 00:42
@nnethercote
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Perf results from landing are as expected.

@RalfJung
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Strange, why did max-rss increase by 15% for some benchmarks?

@Zoxc
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Zoxc commented Feb 11, 2019

@RalfJung You have to store a map to each constant value, which is wasteful if you only have distinct constant values. Maybe that's why? The max-rss benchmarks are also noisy =P

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And inflate and keccak are particularly noisy. Earlier runs didn't show a regression for them.

@oli-obk oli-obk added the beta-nominated Nominated for backporting to the compiler in the beta channel. label Feb 11, 2019
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oli-obk commented Feb 11, 2019

nominating for beta backport as per #57829 (comment)

We can also create a less invasive backport by just doing the changes in https://github.com/rust-lang/rust/pull/58207/files#diff-c8a6d543f758cb294320bcac3b5268ae without renaming the method

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triage, beta-accepted.

@pnkfelix pnkfelix added the beta-accepted Accepted for backporting to the compiler in the beta channel. label Feb 14, 2019
@pietroalbini pietroalbini mentioned this pull request Feb 17, 2019
Merged
@pietroalbini pietroalbini removed beta-nominated Nominated for backporting to the compiler in the beta channel. labels Feb 17, 2019
bors added a commit that referenced this pull request Feb 17, 2019
@bors
Auto merge of #58537 - pietroalbini:beta-backports, r=pietroalbini
1456495 
[beta] Rollup backports

Cherry-picked:

* #58207: Make `intern_lazy_const` actually intern its argument.
* #58161: Lower constant patterns with ascribed types.
* #57908: resolve: Fix span arithmetics in the import conflict error
* #57835: typeck: remove leaky nested probe during trait object method resolution
* #57885: Avoid committing to autoderef in object method probing
* #57646: Fixes text becoming invisible when element targetted

Rolled up:

* #58522: [BETA] Update cargo

r? @ghost
bors added a commit that referenced this pull request Feb 20, 2019
@bors
Auto merge of #58537 - pietroalbini:beta-backports, r=pietroalbini
1f84156 
[beta] Rollup backports

Cherry-picked:

* #58207: Make `intern_lazy_const` actually intern its argument.
* #58161: Lower constant patterns with ascribed types.
* #57908: resolve: Fix span arithmetics in the import conflict error
* #57835: typeck: remove leaky nested probe during trait object method resolution
* #57885: Avoid committing to autoderef in object method probing
* #57646: Fixes text becoming invisible when element targetted

Rolled up:

* #58522: [BETA] Update cargo

r? @ghost
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