Stabilize support for Profile-guided Optimization #61268
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Team member @michaelwoerister has proposed to merge this. The next step is review by the rest of the tagged team members:
No concerns currently listed. Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up! See this document for info about what commands tagged team members can give me. |
alexcrichton
approved these changes
May 28, 2019
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| - It is recommended to use *absolute paths* for the argument of | ||
| `-Cprofile-generate` and `-Cprofile-use`. Cargo can invoke `rustc` with | ||
| varying working directories, meaning that `.profraw` files might show up |
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Hm this isn't quite right I think, don't .profraw files show up in the cwd by default? When compiling with profile-use, however, I think you definitely want to use absolute paths.
That being said absolute paths I think are still always your best bet.
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True, things would still work for the "generate" case. I'll re-word but keep the recommendation for using absolute paths.
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The job Click to expand the log.I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact |
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☔ The latest upstream changes (presumably #61274) made this pull request unmergeable. Please resolve the merge conflicts. |
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@alexcrichton, I removed the |
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I mentioned above that I wouldn't switch CGUs by default just yet, but I would also expect ThinLTO to take PGO data into account to know what to inline, but I could very well be wrong about that! |
OK, let's keep the two settings independent then. ThinLTO should indeed take PGO data into account since PGO adds regular This is mostly my general slight mistrust in (Thin)LTO speaking. It's just one more step where things can go wrong (and have done so in the past). I personally would always default to one CGU for any kind of production code. But that's a topic for another discussion |
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☔ The latest upstream changes (presumably #61005) made this pull request unmergeable. Please resolve the merge conflicts. |
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alexcrichton
approved these changes
Jun 4, 2019
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🔔 This is now entering its final comment period, as per the review above. 🔔 |
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The final comment period, with a disposition to merge, as per the review above, is now complete. As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed. The RFC will be merged soon. |
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☔ The latest upstream changes (presumably #61739) made this pull request unmergeable. Please resolve the merge conflicts. |
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@bors r=alexcrichton (right?) |
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📌 Commit b7fe2ca has been approved by |
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This PR doesn't appear on https://buildbot2.rust-lang.org/homu/queue/rust |
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@bors: r+ |
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💡 This pull request was already approved, no need to approve it again.
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📌 Commit b7fe2ca has been approved by |
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⌛ Testing commit b7fe2ca with merge 30fcafb37fb86899f2be848f1507848f4049c8eb... |
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@bors p=50 |
bors
added a commit
that referenced
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Jul 2, 2019
Stabilize support for Profile-guided Optimization This PR makes profile-guided optimization available via the `-C profile-generate` / `-C profile-use` pair of commandline flags and adds end-user documentation for the feature to the [rustc book](https://doc.rust-lang.org/rustc/). The PR thus ticks the last two remaining checkboxes of the [stabilization tracking issue](#59913). From the tracking issue: > Profile-guided optimization (PGO) is a common optimization technique for ahead-of-time compilers. It works by collecting data about a program's typical execution (e.g. probability of branches taken, typical runtime values of variables, etc) and then uses this information during program optimization for things like inlining decisions, machine code layout, or indirect call promotion. If you are curious about how this can be used, there is a rendered version of the documentation this PR adds available [here]( https://github.com/michaelwoerister/rust/blob/stabilize-pgo/src/doc/rustc/src/profile-guided-optimization.md). r? @alexcrichton cc @rust-lang/compiler
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☀️ Test successful - checks-azure, checks-travis, status-appveyor |
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netbsd-srcmastr
pushed a commit
to NetBSD/pkgsrc
that referenced
this pull request
Aug 29, 2019
Pkgsrc changes:
* Add a patch to llvm to deal with const dli_saddr.
* Adapt two other patches.
* Cross-build currently fails, so i386, powerpc and sparc64 bootstrap
kits for 1.37.0 are built natively. Missing aarch64 hardware, so that's
not available yet.
* Bump bootstrap requirements to 1.36.0 except for armv7-unknown-netbsd-eabihf
which I've not managed to cross-build.
Upstream changes:
Version 1.37.0 (2019-08-15)
==========================
Language
--------
- `#[must_use]` will now warn if the type is contained in a [tuple][61100],
[`Box`][62228], or an [array][62235] and unused.
- [You can now use the `cfg` and `cfg_attr` attributes on
generic parameters.][61547]
- [You can now use enum variants through type alias.][61682] e.g. You can
write the following:
```rust
type MyOption = Option<u8>;
fn increment_or_zero(x: MyOption) -> u8 {
match x {
MyOption::Some(y) => y + 1,
MyOption::None => 0,
}
}
```
- [You can now use `_` as an identifier for consts.][61347] e.g. You can write
`const _: u32 = 5;`.
- [You can now use `#[repr(align(X)]` on enums.][61229]
- [The `?`/_"Kleene"_ macro operator is now available in the
2015 edition.][60932]
Compiler
--------
- [You can now enable Profile-Guided Optimization with the `-C profile-generate`
and `-C profile-use` flags.][61268] For more information on how to use profile
guided optimization, please refer to the [rustc book][rustc-book-pgo].
- [The `rust-lldb` wrapper script should now work again.][61827]
Libraries
---------
- [`mem::MaybeUninit<T>` is now ABI-compatible with `T`.][61802]
Stabilized APIs
---------------
- [`BufReader::buffer`]
- [`BufWriter::buffer`]
- [`Cell::from_mut`]
- [`Cell<[T]>::as_slice_of_cells`][`Cell<slice>::as_slice_of_cells`]
- [`DoubleEndedIterator::nth_back`]
- [`Option::xor`]
- [`Wrapping::reverse_bits`]
- [`i128::reverse_bits`]
- [`i16::reverse_bits`]
- [`i32::reverse_bits`]
- [`i64::reverse_bits`]
- [`i8::reverse_bits`]
- [`isize::reverse_bits`]
- [`slice::copy_within`]
- [`u128::reverse_bits`]
- [`u16::reverse_bits`]
- [`u32::reverse_bits`]
- [`u64::reverse_bits`]
- [`u8::reverse_bits`]
- [`usize::reverse_bits`]
Cargo
-----
- [`Cargo.lock` files are now included by default when publishing executable crates
with executables.][cargo/7026]
- [You can now specify `default-run="foo"` in `[package]` to specify the
default executable to use for `cargo run`.][cargo/7056]
Misc
----
Compatibility Notes
-------------------
- [Using `...` for inclusive range patterns will now warn by default.][61342]
Please transition your code to using the `..=` syntax for inclusive
ranges instead.
- [Using a trait object without the `dyn` will now warn by default.][61203]
Please transition your code to use `dyn Trait` for trait objects instead.
[62228]: rust-lang/rust#62228
[62235]: rust-lang/rust#62235
[61802]: rust-lang/rust#61802
[61827]: rust-lang/rust#61827
[61547]: rust-lang/rust#61547
[61682]: rust-lang/rust#61682
[61268]: rust-lang/rust#61268
[61342]: rust-lang/rust#61342
[61347]: rust-lang/rust#61347
[61100]: rust-lang/rust#61100
[61203]: rust-lang/rust#61203
[61229]: rust-lang/rust#61229
[60932]: rust-lang/rust#60932
[cargo/7026]: rust-lang/cargo#7026
[cargo/7056]: rust-lang/cargo#7056
[`BufReader::buffer`]: https://doc.rust-lang.org/std/io/struct.BufReader.html#method.buffer
[`BufWriter::buffer`]: https://doc.rust-lang.org/std/io/struct.BufWriter.html#method.buffer
[`Cell::from_mut`]: https://doc.rust-lang.org/std/cell/struct.Cell.html#method.from_mut
[`Cell<slice>::as_slice_of_cells`]: https://doc.rust-lang.org/std/cell/struct.Cell.html#method.as_slice_of_cells
[`DoubleEndedIterator::nth_back`]: https://doc.rust-lang.org/std/iter/trait.DoubleEndedIterator.html#method.nth_back
[`Option::xor`]: https://doc.rust-lang.org/std/option/enum.Option.html#method.xor
[`RefCell::try_borrow_unguarded`]: https://doc.rust-lang.org/std/cell/struct.RefCell.html#method.try_borrow_unguarded
[`Wrapping::reverse_bits`]: https://doc.rust-lang.org/std/num/struct.Wrapping.html#method.reverse_bits
[`i128::reverse_bits`]: https://doc.rust-lang.org/std/primitive.i128.html#method.reverse_bits
[`i16::reverse_bits`]: https://doc.rust-lang.org/std/primitive.i16.html#method.reverse_bits
[`i32::reverse_bits`]: https://doc.rust-lang.org/std/primitive.i32.html#method.reverse_bits
[`i64::reverse_bits`]: https://doc.rust-lang.org/std/primitive.i64.html#method.reverse_bits
[`i8::reverse_bits`]: https://doc.rust-lang.org/std/primitive.i8.html#method.reverse_bits
[`isize::reverse_bits`]: https://doc.rust-lang.org/std/primitive.isize.html#method.reverse_bits
[`slice::copy_within`]: https://doc.rust-lang.org/std/primitive.slice.html#method.copy_within
[`u128::reverse_bits`]: https://doc.rust-lang.org/std/primitive.u128.html#method.reverse_bits
[`u16::reverse_bits`]: https://doc.rust-lang.org/std/primitive.u16.html#method.reverse_bits
[`u32::reverse_bits`]: https://doc.rust-lang.org/std/primitive.u32.html#method.reverse_bits
[`u64::reverse_bits`]: https://doc.rust-lang.org/std/primitive.u64.html#method.reverse_bits
[`u8::reverse_bits`]: https://doc.rust-lang.org/std/primitive.u8.html#method.reverse_bits
[`usize::reverse_bits`]: https://doc.rust-lang.org/std/primitive.usize.html#method.reverse_bits
[rustc-book-pgo]: https://doc.rust-lang.org/rustc/profile-guided-optimization.html
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This PR makes profile-guided optimization available via the
-C profile-generate/-C profile-usepair of commandline flags and adds end-user documentation for the feature to the rustc book. The PR thus ticks the last two remaining checkboxes of the stabilization tracking issue.From the tracking issue:
If you are curious about how this can be used, there is a rendered version of the documentation this PR adds available here.
r? @alexcrichton
cc @rust-lang/compiler