Inline cfg(bootstrap) version of debug_assertions intrinsic
#121112
Closed
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This speeds up the stage1 build of the library by about 10s on my computer.
rustbot
added
S-waiting-on-review
|
Ah, in bootstrap, not the version used later. Yup, makes sense to me. @bors r+ |
bors
added
S-waiting-on-bors
|
☔ The latest upstream changes (presumably #120500) made this pull request unmergeable. Please resolve the merge conflicts. |
bors
added
S-waiting-on-author
|
I think have a nicer and more effective solution to fix the rustc perf impact. |
Noratrieb
added a commit
to Noratrieb/rust
that referenced
this pull request
Feb 20, 2024
…aethlin Always inline check in `assert_unsafe_precondition` with cfg(debug_assertions) The current complexities in `assert_unsafe_precondition` are delicately balancing several concerns, among them compile times for the cases where there are no debug assertions. This comes at a large runtime cost when the assertions are enabled, making the debug assertion compiler a lot slower, which is very annoying. To avoid this, we always inline the check when building with debug assertions. Numbers (compiling stage1 library after touching core): - master: 80s - just adding `#[inline(always)]` to the `cfg(bootstrap)` `debug_assertions` (equivalent to a bootstrap bump (uhh, i just realized that i was on a slightly outdated master so this bump might have happened already), (rust-lang#121112)): 67s - this: 54s So this seems like a good solution. I think we can still get the same run-time perf improvements for other users too by massaging this code further (see my other PR about adding `#[rustc_no_mir_inline]` rust-lang#121114) but this is a simpler step that solves the imminent problem of "holy shit my rustc is sooo slow". Funny consequence: This now means compiling the standard library with dbeug assertions makes it faster (than without, when using debug assertions downstream)! r? `@saethlin` (or anyone else if someone wants to review this) fixes rust-lang#121110, supposedly
Noratrieb
added a commit
to Noratrieb/rust
that referenced
this pull request
Feb 20, 2024
…aethlin Always inline check in `assert_unsafe_precondition` with cfg(debug_assertions) The current complexities in `assert_unsafe_precondition` are delicately balancing several concerns, among them compile times for the cases where there are no debug assertions. This comes at a large runtime cost when the assertions are enabled, making the debug assertion compiler a lot slower, which is very annoying. To avoid this, we always inline the check when building with debug assertions. Numbers (compiling stage1 library after touching core): - master: 80s - just adding `#[inline(always)]` to the `cfg(bootstrap)` `debug_assertions` (equivalent to a bootstrap bump (uhh, i just realized that i was on a slightly outdated master so this bump might have happened already), (rust-lang#121112)): 67s - this: 54s So this seems like a good solution. I think we can still get the same run-time perf improvements for other users too by massaging this code further (see my other PR about adding `#[rustc_no_mir_inline]` rust-lang#121114) but this is a simpler step that solves the imminent problem of "holy shit my rustc is sooo slow". Funny consequence: This now means compiling the standard library with dbeug assertions makes it faster (than without, when using debug assertions downstream)! r? ``@saethlin`` (or anyone else if someone wants to review this) fixes rust-lang#121110, supposedly
Noratrieb
added a commit
to Noratrieb/rust
that referenced
this pull request
Feb 20, 2024
…aethlin Always inline check in `assert_unsafe_precondition` with cfg(debug_assertions) The current complexities in `assert_unsafe_precondition` are delicately balancing several concerns, among them compile times for the cases where there are no debug assertions. This comes at a large runtime cost when the assertions are enabled, making the debug assertion compiler a lot slower, which is very annoying. To avoid this, we always inline the check when building with debug assertions. Numbers (compiling stage1 library after touching core): - master: 80s - just adding `#[inline(always)]` to the `cfg(bootstrap)` `debug_assertions` (equivalent to a bootstrap bump (uhh, i just realized that i was on a slightly outdated master so this bump might have happened already), (rust-lang#121112)): 67s - this: 54s So this seems like a good solution. I think we can still get the same run-time perf improvements for other users too by massaging this code further (see my other PR about adding `#[rustc_no_mir_inline]` rust-lang#121114) but this is a simpler step that solves the imminent problem of "holy shit my rustc is sooo slow". Funny consequence: This now means compiling the standard library with dbeug assertions makes it faster (than without, when using debug assertions downstream)! r? ```@saethlin``` (or anyone else if someone wants to review this) fixes rust-lang#121110, supposedly
rust-timer
added a commit
to rust-lang-ci/rust
that referenced
this pull request
Feb 20, 2024
Rollup merge of rust-lang#121196 - Nilstrieb:the-clever-solution, r=saethlin Always inline check in `assert_unsafe_precondition` with cfg(debug_assertions) The current complexities in `assert_unsafe_precondition` are delicately balancing several concerns, among them compile times for the cases where there are no debug assertions. This comes at a large runtime cost when the assertions are enabled, making the debug assertion compiler a lot slower, which is very annoying. To avoid this, we always inline the check when building with debug assertions. Numbers (compiling stage1 library after touching core): - master: 80s - just adding `#[inline(always)]` to the `cfg(bootstrap)` `debug_assertions` (equivalent to a bootstrap bump (uhh, i just realized that i was on a slightly outdated master so this bump might have happened already), (rust-lang#121112)): 67s - this: 54s So this seems like a good solution. I think we can still get the same run-time perf improvements for other users too by massaging this code further (see my other PR about adding `#[rustc_no_mir_inline]` rust-lang#121114) but this is a simpler step that solves the imminent problem of "holy shit my rustc is sooo slow". Funny consequence: This now means compiling the standard library with dbeug assertions makes it faster (than without, when using debug assertions downstream)! r? ```@saethlin``` (or anyone else if someone wants to review this) fixes rust-lang#121110, supposedly
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
5 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This speeds up the stage1 build of the library by about 10s on my computer.
helps with #121110