Add the unstable option to reduce the binary size of dynamic library… #118636

h1467792822 · 2023-12-05T05:06:29Z

Motivation

The average length of symbol names in the rust standard library is about 100 bytes, while the average length of symbol names in the C++ standard library is about 65 bytes. In some embedded environments where dynamic library are widely used, rust dynamic library symbol name space hash become one of the key bottlenecks of application, Especially when the existing C/C++ module is reconstructed into the rust module.

The unstable option -Z symbol_mangling_version=hashed is added to solve the bottleneck caused by too long dynamic library symbol names.

Test data

The following is a set of test data on the ubuntu 18.04 LTS environment. With this plug-in, the space saving rate of dynamic libraries can reach about 20%.

The test object is the standard library of rust (built based on Xargo), tokio crate, and hyper crate.

The contents of the Cargo.toml file in the construction project of the three dynamic libraries are as follows:

# Cargo.toml
[profile.release]
panic = "abort"
opt-leve="z"
codegen-units=1
strip=true
debug=true

The built dynamic library also removes the .rustc segments that are not needed at run time and then compares the size. The detailed data is as follows:

libstd.so

symbol_mangling_version size saving rate

legacy 804896

hashed 608288 0.244

v0 858144

hashed 608288 0.291

libhyper.so

symbol_mangling_version(libhyper.so) symbol_mangling_version(libstd.so) size saving rate

legacy legacy 866312

hashed legacy 645128 0.255

legacy hashed 854024

hashed hashed 632840 0.259

rustbot · 2023-12-05T05:06:37Z

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @cjgillot (or someone else) soon.

Please see the contribution instructions for more information. Namely, in order to ensure the minimum review times lag, PR authors and assigned reviewers should ensure that the review label (S-waiting-on-review and S-waiting-on-author) stays updated, invoking these commands when appropriate:

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h1467792822 · 2023-12-05T06:20:21Z

r? @m-ou-se

m-ou-se · 2023-12-14T11:39:27Z

20%

Exciting results!

This will have to be reviewed by the compiler team. I imagine they might want an MCP first.

r? compiler

compiler-errors · 2023-12-14T14:37:27Z

Yes, please open an MCP. Also this needs a test or something that demonstrates it's working correctly.

@rustbot author

bors · 2023-12-14T18:25:09Z

☔ The latest upstream changes (presumably #118937) made this pull request unmergeable. Please resolve the merge conflicts.

michaelwoerister · 2023-12-19T08:47:43Z

Thanks for the PR and the MCP, @h1467792822! Looks very promising 🙂

r? @michaelwoerister

h1467792822 · 2024-01-03T01:23:45Z

@rustbot ready

Add the unstable option to reduce the binary size of dynamic library… # Motivation The average length of symbol names in the rust standard library is about 100 bytes, while the average length of symbol names in the C++ standard library is about 65 bytes. In some embedded environments where dynamic library are widely used, rust dynamic library symbol name space hash become one of the key bottlenecks of application, Especially when the existing C/C++ module is reconstructed into the rust module. The unstable option `-Z symbol_mangling_version=hashed` is added to solve the bottleneck caused by too long dynamic library symbol names. ## Test data The following is a set of test data on the ubuntu 18.04 LTS environment. With this plug-in, the space saving rate of dynamic libraries can reach about 20%. The test object is the standard library of rust (built based on Xargo), tokio crate, and hyper crate. The contents of the Cargo.toml file in the construction project of the three dynamic libraries are as follows: ```txt # Cargo.toml [profile.release] panic = "abort" opt-leve="z" codegen-units=1 strip=true debug=true ``` The built dynamic library also removes the `.rustc` segments that are not needed at run time and then compares the size. The detailed data is as follows: 1. libstd.so > | symbol_mangling_version | size | saving rate | > | --- | --- | --- | > | legacy | 804896 || > | hashed | 608288 | 0.244 | > | v0 | 858144 || > | hashed | 608288 | 0.291 | 2. libhyper.so > | symbol_mangling_version(libhyper.so) | symbol_mangling_version(libstd.so) | size | saving rate | > | --- | --- | --- | --- | > | legacy | legacy | 866312 || > | hashed | legacy | 645128 |0.255| > | legacy | hashed | 854024 || > | hashed | hashed | 632840 |0.259|

bors · 2024-01-25T17:09:02Z

💔 Test failed - checks-actions

…ed -Z unstable-options` to shorten symbol names by replacing them with a digest. Enrich test cases

h1467792822 · 2024-01-26T05:59:06Z

@michaelwoerister Sorry, the code I submitted failed the test again.
I compared the other test cases and found that I still need to add # ignore-cross-compile to the Makefile (I mistakenly deleted it last time I submitted it).
I verify in the local musl environment. After the modification, no error is reported when ./x.py test tests/run-make/symbol-mangling-hashed --stage 1 --target x86_64-unknown-linux-musl is executed.
If the modification is incorrect, please give me some advice again. Thank you!

michaelwoerister · 2024-01-26T09:11:35Z

Thanks, @h1467792822 -- that seems like an appropriate solution. The cross-compiling issue is not related to what's being tested here, as far as I can tell.

@bors r+

bors · 2024-01-26T09:11:38Z

📌 Commit 6e53e66 has been approved by michaelwoerister

It is now in the queue for this repository.

Add the unstable option to reduce the binary size of dynamic library… # Motivation The average length of symbol names in the rust standard library is about 100 bytes, while the average length of symbol names in the C++ standard library is about 65 bytes. In some embedded environments where dynamic library are widely used, rust dynamic library symbol name space hash become one of the key bottlenecks of application, Especially when the existing C/C++ module is reconstructed into the rust module. The unstable option `-Z symbol_mangling_version=hashed` is added to solve the bottleneck caused by too long dynamic library symbol names. ## Test data The following is a set of test data on the ubuntu 18.04 LTS environment. With this plug-in, the space saving rate of dynamic libraries can reach about 20%. The test object is the standard library of rust (built based on Xargo), tokio crate, and hyper crate. The contents of the Cargo.toml file in the construction project of the three dynamic libraries are as follows: ```txt # Cargo.toml [profile.release] panic = "abort" opt-leve="z" codegen-units=1 strip=true debug=true ``` The built dynamic library also removes the `.rustc` segments that are not needed at run time and then compares the size. The detailed data is as follows: 1. libstd.so > | symbol_mangling_version | size | saving rate | > | --- | --- | --- | > | legacy | 804896 || > | hashed | 608288 | 0.244 | > | v0 | 858144 || > | hashed | 608288 | 0.291 | 2. libhyper.so > | symbol_mangling_version(libhyper.so) | symbol_mangling_version(libstd.so) | size | saving rate | > | --- | --- | --- | --- | > | legacy | legacy | 866312 || > | hashed | legacy | 645128 |0.255| > | legacy | hashed | 854024 || > | hashed | hashed | 632840 |0.259|

bors · 2024-01-26T17:15:02Z

⌛ Testing commit 6e53e66 with merge eb8e55a...

bors · 2024-01-26T21:30:02Z

💥 Test timed out

fmease · 2024-01-26T21:43:31Z

@bors retry timeout (reoccurring)

rust-log-analyzer · 2024-01-26T21:45:23Z

A job failed! Check out the build log: (web) (plain)

Click to see the possible cause of the failure (guessed by this bot)

bors · 2024-01-27T02:32:33Z

⌛ Testing commit 6e53e66 with merge 04521fd...

Add the unstable option to reduce the binary size of dynamic library… # Motivation The average length of symbol names in the rust standard library is about 100 bytes, while the average length of symbol names in the C++ standard library is about 65 bytes. In some embedded environments where dynamic library are widely used, rust dynamic library symbol name space hash become one of the key bottlenecks of application, Especially when the existing C/C++ module is reconstructed into the rust module. The unstable option `-Z symbol_mangling_version=hashed` is added to solve the bottleneck caused by too long dynamic library symbol names. ## Test data The following is a set of test data on the ubuntu 18.04 LTS environment. With this plug-in, the space saving rate of dynamic libraries can reach about 20%. The test object is the standard library of rust (built based on Xargo), tokio crate, and hyper crate. The contents of the Cargo.toml file in the construction project of the three dynamic libraries are as follows: ```txt # Cargo.toml [profile.release] panic = "abort" opt-leve="z" codegen-units=1 strip=true debug=true ``` The built dynamic library also removes the `.rustc` segments that are not needed at run time and then compares the size. The detailed data is as follows: 1. libstd.so > | symbol_mangling_version | size | saving rate | > | --- | --- | --- | > | legacy | 804896 || > | hashed | 608288 | 0.244 | > | v0 | 858144 || > | hashed | 608288 | 0.291 | 2. libhyper.so > | symbol_mangling_version(libhyper.so) | symbol_mangling_version(libstd.so) | size | saving rate | > | --- | --- | --- | --- | > | legacy | legacy | 866312 || > | hashed | legacy | 645128 |0.255| > | legacy | hashed | 854024 || > | hashed | hashed | 632840 |0.259|

bors · 2024-01-27T04:29:10Z

☀️ Test successful - checks-actions
Approved by: michaelwoerister
Pushing 04521fd to master...

rust-timer · 2024-01-27T06:20:43Z

Finished benchmarking commit (04521fd): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

This benchmark run did not return any relevant results for this metric.

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)	-	-	0
Regressions ❌ (secondary)	2.7%	[2.7%, 2.7%]	1
Improvements ✅ (primary)	-3.2%	[-3.2%, -3.2%]	1
Improvements ✅ (secondary)	-3.7%	[-3.7%, -3.7%]	1
All ❌✅ (primary)	-3.2%	[-3.2%, -3.2%]	1

Cycles

This benchmark run did not return any relevant results for this metric.

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 660.976s -> 660.806s (-0.03%)
Artifact size: 308.12 MiB -> 308.11 MiB (-0.00%)

rustbot assigned cjgillot Dec 5, 2023

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Dec 5, 2023