[WIP] make nightly compilers able to parallelize #101566

SparrowLii · 2022-09-08T09:17:36Z

Try to complete the work of #59667. Refactor data structures such as Lock to make parallel compilation available while minimizing regressions and remaining thread safety.

lqd · 2022-09-08T09:52:43Z

@bors try @rust-timer queue

rust-timer · 2022-09-08T09:52:45Z

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

bors · 2022-09-08T09:52:53Z

⌛ Trying commit 9201feb16c93bd27499fb0625495e7f6bf447bfd with merge 49d1d103e085e772150709059f0bbb75c5a37a89...

Nilstrieb · 2022-09-08T10:08:54Z

compiler/rustc_data_structures/src/sync.rs

+#[cfg(not(parallel_compiler))]
+static mut SHARED: bool = false;
+#[cfg(parallel_compiler)]
+static mut SHARED: bool = true;


Can you use the unstable SyncUnsafeCell<T> instead of static mut for both versions? This would be a great place to test it out.

Thanks, will try it!

is it ever mutated ?

not for now, but I think we should change it based on -Z threads=n option in a early stage of compilation

We use SyncUnsafeCell<T> now

Nilstrieb · 2022-09-08T10:10:20Z

compiler/rustc_data_structures/src/sync.rs

+static THREADS_COUNTER: std::sync::atomic::AtomicU32 = std::sync::atomic::AtomicU32::new(0);
+
+fn next() -> u32 {
+    THREADS_COUNTER.fetch_add(1, SeqCst)


This can be Relaxed instead

bors · 2022-09-08T11:43:15Z

☀️ Try build successful - checks-actions
Build commit: 49d1d103e085e772150709059f0bbb75c5a37a89 (49d1d103e085e772150709059f0bbb75c5a37a89)

rust-timer · 2022-09-08T11:43:17Z

Queued 49d1d103e085e772150709059f0bbb75c5a37a89 with parent 44adfcc, future comparison URL.

rust-timer · 2022-09-08T22:19:41Z

Finished benchmarking commit (49d1d103e085e772150709059f0bbb75c5a37a89): comparison URL.

Overall result: ❌ regressions - ACTION NEEDED

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please fix the regressions and do another perf run. If the next run shows neutral or positive results, the label will be automatically removed.

@bors rollup=never
@rustbot label: +S-waiting-on-review -S-waiting-on-perf +perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean¹	range	count²
Regressions ❌ (primary)	7.9%	[0.6%, 15.7%]	239
Regressions ❌ (secondary)	7.6%	[0.3%, 31.7%]	250
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	7.9%	[0.6%, 15.7%]	239

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean¹	range	count²
Regressions ❌ (primary)	1.5%	[1.2%, 1.7%]	3
Regressions ❌ (secondary)	2.4%	[1.5%, 4.4%]	15
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.0%	[-3.5%, -2.7%]	3
All ❌✅ (primary)	1.5%	[1.2%, 1.7%]	3

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean¹	range	count²
Regressions ❌ (primary)	4.5%	[1.4%, 8.2%]	173
Regressions ❌ (secondary)	5.0%	[1.7%, 18.7%]	168
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	4.5%	[1.4%, 8.2%]	173

the arithmetic mean of the percent change ↩ ↩² ↩³
number of relevant changes ↩ ↩² ↩³

SparrowLii · 2022-09-08T23:34:17Z

Well, the refactored implementation of Lock still reduces the overall efficiency of the compiler by around 8%, which is frustrating but not unexpected.
In fact, I have some crazier ideas for parallel compilation without losing efficiency, which means a new language feature.
That is, if we could allow 'incomplete' generic parameters in struct declarations like this:

trait S<T> {
    type Item = T;
}

struct MyStruct<S<_>> {
    feild1: S<u8>,
    feild2: S<i32>,
    feild3: S<f64>,
}

We only need to decide whether S is RefCell or Mutex, and we can implement both shared and non-shared instances for MyStruct.
I think it's a very exciting idea, and I'll go get more perspectives in the community.

vacuus · 2022-09-09T00:45:52Z

If I'm not mistaken, the proposed code is using some sort of higher-kinded type (HKT) feature. The generic associated type feature is close to being ~~merged~~ stabilized (#96709), and is a subset of a theoretical HKT feature. I'm not remotely a lang dev, but GATs have been hard enough to be mostly accepted, and based on the discussion in that PR, getting full HKTs will at least be a slog. At least discussion around HKTs can use parallel rustc as a motivating example. GATs might need to be more established within the culture before HKTs have a fighting chance to be implemented.
In any case, parallel rustc is an awesome effort. Much thanks to you and all the other contributors!

SparrowLii · 2022-09-09T08:43:13Z

Let me try if we can solve the above mentioned problem with GAT.

eggyal · 2022-09-09T08:54:19Z

The pattern can be achieved with GATs: https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021&gist=c087b818a1f98c23bf6df235c193e9cf

SparrowLii · 2022-10-12T11:20:38Z

Since std::sync::Mutex was optimized not long ago, let's try using it first

Kobzol · 2022-10-12T11:50:14Z

@bors try @rust-timer queue

rust-timer · 2022-10-12T11:50:15Z

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

bors · 2022-10-12T11:50:23Z

⌛ Trying commit 0ecf80ccd388abf402c417ffad6ce2cafd864bed with merge d7be50832a0dcadf25609eb8b25f87da3e05dbb3...

bors · 2022-10-12T13:43:41Z

☀️ Try build successful - checks-actions
Build commit: d7be50832a0dcadf25609eb8b25f87da3e05dbb3 (d7be50832a0dcadf25609eb8b25f87da3e05dbb3)

rust-timer · 2022-10-12T13:43:43Z

Queued d7be50832a0dcadf25609eb8b25f87da3e05dbb3 with parent e6ce562, future comparison URL.

rust-timer · 2022-10-12T15:04:35Z

Finished benchmarking commit (d7be50832a0dcadf25609eb8b25f87da3e05dbb3): comparison URL.

Overall result: ❌ regressions - ACTION NEEDED

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please fix the regressions and do another perf run. If the next run shows neutral or positive results, the label will be automatically removed.

@bors rollup=never
@rustbot label: +S-waiting-on-review -S-waiting-on-perf +perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean¹	range	count²
Regressions ❌ (primary)	4.6%	[0.4%, 10.2%]	230
Regressions ❌ (secondary)	4.6%	[0.4%, 18.1%]	241
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	4.6%	[0.4%, 10.2%]	230

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean¹	range	count²
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-2.8%	[-2.8%, -2.7%]	2
Improvements ✅ (secondary)	-2.7%	[-3.7%, -2.0%]	26
All ❌✅ (primary)	-2.8%	[-2.8%, -2.7%]	2

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean¹	range	count²
Regressions ❌ (primary)	5.4%	[1.6%, 13.2%]	191
Regressions ❌ (secondary)	6.8%	[2.1%, 25.8%]	201
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	5.4%	[1.6%, 13.2%]	191

the arithmetic mean of the percent change ↩ ↩² ↩³
number of relevant changes ↩ ↩² ↩³

bors · 2023-04-23T03:39:23Z

⌛ Trying commit f925ea0 with merge da328d6533d0dfe64e6cfd676472a6b2057b2aa9...

bors · 2023-04-23T05:21:23Z

☀️ Try build successful - checks-actions
Build commit: da328d6533d0dfe64e6cfd676472a6b2057b2aa9 (da328d6533d0dfe64e6cfd676472a6b2057b2aa9)

rust-timer · 2023-04-23T07:33:03Z

Finished benchmarking commit (da328d6533d0dfe64e6cfd676472a6b2057b2aa9): comparison URL.

Overall result: ❌ regressions - ACTION NEEDED

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please fix the regressions and do another perf run. If the next run shows neutral or positive results, the label will be automatically removed.

@bors rollup=never
@rustbot label: -S-waiting-on-perf +perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	3.7%	[0.3%, 6.5%]	221
Regressions ❌ (secondary)	3.7%	[0.6%, 10.3%]	234
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	3.7%	[0.3%, 6.5%]	221

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	6.6%	[0.7%, 18.9%]	127
Regressions ❌ (secondary)	4.4%	[0.8%, 15.8%]	128
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.8%	[-3.8%, -3.8%]	1
All ❌✅ (primary)	6.6%	[0.7%, 18.9%]	127

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	4.7%	[0.7%, 20.8%]	207
Regressions ❌ (secondary)	5.1%	[1.2%, 10.6%]	204
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	4.7%	[0.7%, 20.8%]	207

Introduce `DynSend` and `DynSync` auto trait for parallel compiler part of parallel-rustc rust-lang#101566 This PR introduces `DynSend / DynSync` trait and `FromDyn / IntoDyn` structure in rustc_data_structure::marker. `FromDyn` can dynamically check data structures for thread safety when switching to parallel environments (such as calling `par_for_each_in`). This happens only when `-Z threads > 1` so it doesn't affect single-threaded mode's compile efficiency. r? `@cjgillot`

SparrowLii · 2023-05-19T08:30:29Z

(1) Switch serial/parallel at runtime(refactor Lock、Sharded、RwLock etc. in rustc_data_structures)
(2) Specialization for QueryCache
(3) Enable parallel compilation only in Full and IncrFull scenarios

With methods above, under 8 threads, Full and IncrFull have an average performance improvement of 10.6%, while IncrUnchanged and IncrPatched have a regression of 3.8%.
#109776 (comment)
Under single thread, the regression is 2.1% on average.
#109776 (comment)

SparrowLii · 2023-08-08T10:43:40Z

We have solved perf problem under multi-threads at current, and will finish the work under single thread this month.

bjorn3 · 2023-11-24T13:00:30Z

#117435 has enabled parallel rustc on nightly.

SparrowLii · 2023-11-25T00:48:52Z

Yea, we should close this now

rustbot added the T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. label Sep 8, 2022

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Sep 8, 2022

Nilstrieb reviewed Sep 8, 2022

View reviewed changes

rustbot added perf-regression Performance regression. S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-perf Status: Waiting on a perf run to be completed. labels Sep 8, 2022

SparrowLii force-pushed the sync_data_structure branch from 9201feb to 0ecf80c Compare October 12, 2022 11:19

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Oct 12, 2022

rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Oct 12, 2022

rustbot added the A-query-system Area: The rustc query system (https://rustc-dev-guide.rust-lang.org/query.html) label Oct 24, 2022

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rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Apr 23, 2023

Dylan-DPC marked this pull request as draft May 20, 2023 13:58

SparrowLii mentioned this pull request Aug 2, 2023

get auto traits for parallel rustc #114321

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SparrowLii closed this Nov 25, 2023

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[WIP] make nightly compilers able to parallelize #101566

[WIP] make nightly compilers able to parallelize #101566

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[WIP] make nightly compilers able to parallelize #101566

[WIP] make nightly compilers able to parallelize #101566

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Overall result: ❌ regressions - ACTION NEEDED

Footnotes

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rust-timer commented Oct 12, 2022

Overall result: ❌ regressions - ACTION NEEDED

Footnotes

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Overall result: ❌ regressions - ACTION NEEDED

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