Call the OS function to set the main thread's name on program init #97191

wesleywiser · 2022-05-19T21:27:45Z

Normally, Thread::spawn takes care of setting the thread's name, if
one was provided, but since the main thread wasn't created by calling
Thread::spawn, we need to call that function in std::rt::init.

This is mainly useful for system tools like debuggers and profilers
which might show the thread name to a user. Prior to these changes, gdb
and WinDbg would show all thread names except the main thread's name to
a user. I've validated that this patch resolves the issue for both
debuggers.

rust-highfive · 2022-05-19T21:27:48Z

Hey! It looks like you've submitted a new PR for the library teams!

If this PR contains changes to any rust-lang/rust public library APIs then please comment with r? rust-lang/libs-api @rustbot label +T-libs-api -T-libs to request review from a libs-api team reviewer. If you're unsure where your change falls no worries, just leave it as is and the reviewer will take a look and make a decision to forward on if necessary.

Examples of T-libs-api changes:

Stabilizing library features
Introducing insta-stable changes such as new implementations of existing stable traits on existing stable types
Introducing new or changing existing unstable library APIs (excluding permanently unstable features / features without a tracking issue)
Changing public documentation in ways that create new stability guarantees
Changing observable runtime behavior of library APIs

rust-highfive · 2022-05-19T21:27:49Z

r? @joshtriplett

(rust-highfive has picked a reviewer for you, use r? to override)

ChrisDenton · 2022-05-20T17:36:05Z

This looks reasonable to me and I confirmed it worked. It would be good to add a test for it but I can see that would be awkward considering it's inherently platform-specific and I'm pretty sure the sys modules don't include a way to read the OS thread name.

luqmana · 2022-05-20T19:00:18Z

This looks reasonable to me and I confirmed it worked. It would be good to add a test for it but I can see that would be awkward considering it's inherently platform-specific and I'm pretty sure the sys modules don't include a way to read the OS thread name.

Could probably do it via debuginfo-style tests

wesleywiser · 2022-05-21T02:09:27Z

Good idea! I've added a debuginfo test.

src/test/debuginfo/thread-names.rs

ChrisDenton · 2022-05-21T04:51:21Z

Since most of the libs team have a lot on their plate atm and I'm already invested here...

r? @ChrisDenton

library/std/src/rt.rs

Normally, `Thread::spawn` takes care of setting the thread's name, if one was provided, but since the main thread wasn't created by calling `Thread::spawn`, we need to call that function in `std::rt::init`. This is mainly useful for system tools like debuggers and profilers which might show the thread name to a user. Prior to these changes, gdb and WinDbg would show all thread names except the main thread's name to a user. I've validated that this patch resolves the issue for both debuggers.

ChrisDenton · 2022-06-02T23:13:04Z

@bors r+

bors · 2022-06-02T23:13:06Z

📌 Commit 820ffc8 has been approved by ChrisDenton

bors · 2022-06-03T04:15:30Z

⌛ Testing commit 820ffc8 with merge 32cac736087efb4919a56641d90152aac6b4ca2b...

bors · 2022-06-03T04:46:04Z

💔 Test failed - checks-actions

src/test/debuginfo/thread-names.rs

ChrisDenton · 2022-06-03T16:53:34Z

@bors r+

bors · 2022-06-03T16:53:36Z

📌 Commit 7cb538b has been approved by ChrisDenton

…isDenton Call the OS function to set the main thread's name on program init Normally, `Thread::spawn` takes care of setting the thread's name, if one was provided, but since the main thread wasn't created by calling `Thread::spawn`, we need to call that function in `std::rt::init`. This is mainly useful for system tools like debuggers and profilers which might show the thread name to a user. Prior to these changes, gdb and WinDbg would show all thread names except the main thread's name to a user. I've validated that this patch resolves the issue for both debuggers.

JohnTitor · 2022-06-04T09:05:32Z

Failed in rollup: #97727 (comment)
@bors r- rollup=iffy

Co-authored-by: Chris Denton <[email protected]>

wesleywiser · 2022-06-04T14:22:44Z

Added // ignore-windows-gnu to the test since gdb on Windows doesn't seem to support showing the thread name.

ChrisDenton · 2022-06-04T16:02:56Z

@bors r+

bors · 2022-06-04T16:02:57Z

📌 Commit cb87ce2 has been approved by ChrisDenton

bors · 2022-06-04T20:27:56Z

⌛ Testing commit cb87ce2 with merge 4e725ba...

bors · 2022-06-04T23:14:04Z

☀️ Test successful - checks-actions
Approved by: ChrisDenton
Pushing 4e725ba to master...

rust-highfive · 2022-06-04T23:14:27Z

📣 Toolstate changed by #97191!

Tested on commit 4e725ba.
Direct link to PR: #97191

💔 miri on windows: test-pass → test-fail (cc @oli-obk @RalfJung @eddyb).

@oli-obk

Tested on commit rust-lang/rust@4e725ba. Direct link to PR: <rust-lang/rust#97191> 💔 miri on windows: test-pass → test-fail (cc @oli-obk @RalfJung @eddyb).

rust-timer · 2022-06-05T00:35:53Z

Finished benchmarking commit (4e725ba): comparison url.

Instruction count

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

Max RSS (memory usage)

Results

Primary benchmarks: no relevant changes found
Secondary benchmarks: 🎉 relevant improvements found

	mean¹	max	count²
Regressions 😿 (primary)	N/A	N/A	0
Regressions 😿 (secondary)	N/A	N/A	0
Improvements 🎉 (primary)	N/A	N/A	0
Improvements 🎉 (secondary)	-2.8%	-3.8%	4
All 😿🎉 (primary)	N/A	N/A	0

Cycles

Results

Primary benchmarks: mixed results
Secondary benchmarks: no relevant changes found

	mean¹	max	count²
Regressions 😿 (primary)	2.3%	2.3%	1
Regressions 😿 (secondary)	N/A	N/A	0
Improvements 🎉 (primary)	-2.5%	-2.5%	1
Improvements 🎉 (secondary)	N/A	N/A	0
All 😿🎉 (primary)	-0.1%	-2.5%	2

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

@rustbot label: -perf-regression

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

rust-highfive assigned joshtriplett May 19, 2022

rustbot added the T-libs Relevant to the library team, which will review and decide on the PR/issue. label May 19, 2022

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label May 19, 2022

wesleywiser force-pushed the main_thread_name branch 2 times, most recently from b55e054 to 7f4d65d Compare May 21, 2022 01:14

luqmana reviewed May 21, 2022

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wesleywiser force-pushed the main_thread_name branch from 7f4d65d to d8990a7 Compare May 26, 2022 19:26

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wesleywiser force-pushed the main_thread_name branch from 79ea288 to 820ffc8 Compare May 27, 2022 14:39

ChrisDenton approved these changes Jun 2, 2022

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Dylan-DPC mentioned this pull request Jun 4, 2022

Rollup of 5 pull requests #97727

Closed

bors added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Jun 4, 2022

Update src/test/debuginfo/thread-names.rs

cb87ce2

Co-authored-by: Chris Denton <[email protected]>

wesleywiser force-pushed the main_thread_name branch from 7cb538b to cb87ce2 Compare June 4, 2022 13:57

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-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jun 4, 2022

bors added the merged-by-bors This PR was explicitly merged by bors. label Jun 4, 2022

bors merged commit 4e725ba into rust-lang:master Jun 4, 2022

rustbot added this to the 1.63.0 milestone Jun 4, 2022

rust-highfive mentioned this pull request Jun 4, 2022

miri no longer builds after rust-lang/rust#97191 #97745

Closed

moxian mentioned this pull request Mar 27, 2025

buffer for stdout is heap-allocated #139006

Closed

Call the OS function to set the main thread's name on program init #97191

Call the OS function to set the main thread's name on program init #97191

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wesleywiser commented May 19, 2022

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