Skip to content

Move to Go 1.19 atomics#12391

Merged
dbussink merged 4 commits intovitessio:mainfrom
dbussink:use-stdlib-atomics
Feb 21, 2023
Merged

Move to Go 1.19 atomics#12391
dbussink merged 4 commits intovitessio:mainfrom
dbussink:use-stdlib-atomics

Conversation

@dbussink
Copy link
Member

@dbussink dbussink commented Feb 20, 2023 •
edited
Loading

This change moves to Go 1.19 atomics in favor of the version we had in the sync2 package. The version in that package predates the availability of the new atomics, but for the future we want to use the Go provided ones.

On top of that, we can also use the semaphore from x/sync instead of a custom one in sync2. This cleans up a bunch of additional code from sync2.

Upsides are removing the mostly duplicate code from the standard library (albeit with slight different name) and that the stdlib implementation also guarantees things we can't, such as proper alignment for the atomic variables.

Related Issue(s)

Fixes #12395

Checklist

  • "Backport to:" labels have been added if this change should be back-ported
  • Tests were added or are not required
  • Documentation was added or is not required

@dbussink dbussink added Type: Internal Cleanup Component: General Changes throughout the code base labels Feb 20, 2023
@vitess-bot vitess-bot bot added NeedsDescriptionUpdate The description is not clear or comprehensive enough, and needs work NeedsWebsiteDocsUpdate What it says labels Feb 20, 2023
@vitess-bot
Copy link
Contributor

vitess-bot bot commented Feb 20, 2023 •
edited by frouioui
Loading

Review Checklist

Hello reviewers! 👋 Please follow this checklist when reviewing this Pull Request.

General

  • Ensure that the Pull Request has a descriptive title.
  • If this is a change that users need to know about, please apply the release notes (needs details) label so that merging is blocked unless the summary release notes document is included.
  • If a test is added or modified, there should be a documentation on top of the test to explain what the expected behavior is what the test does.

If a new flag is being introduced:

  • Is it really necessary to add this flag?
  • Flag names should be clear and intuitive (as far as possible)
  • Help text should be descriptive.
  • Flag names should use dashes (-) as word separators rather than underscores (_).

If a workflow is added or modified:

  • Each item in Jobs should be named in order to mark it as required.
  • If the workflow should be required, the maintainer team should be notified.

Bug fixes

  • There should be at least one unit or end-to-end test.
  • The Pull Request description should include a link to an issue that describes the bug.

Non-trivial changes

  • There should be some code comments as to why things are implemented the way they are.

New/Existing features

  • Should be documented, either by modifying the existing documentation or creating new documentation.
  • New features should have a link to a feature request issue or an RFC that documents the use cases, corner cases and test cases.

Backward compatibility

  • Protobuf changes should be wire-compatible.
  • Changes to _vt tables and RPCs need to be backward compatible.
  • vtctl command output order should be stable and awk-able.
  • RPC changes should be compatible with vitess-operator
  • If a flag is removed, then it should also be removed from VTop, if used there.

@dbussink dbussink mentioned this pull request Feb 20, 2023
Closed
4 tasks
@dbussink dbussink removed NeedsDescriptionUpdate The description is not clear or comprehensive enough, and needs work NeedsWebsiteDocsUpdate What it says labels Feb 20, 2023
@dbussink dbussink force-pushed the use-stdlib-atomics branch 3 times, most recently from 7dc8821 to fc7fbdd Compare February 20, 2023 18:33
@dbussink dbussink marked this pull request as ready for review February 20, 2023 19:49
shlomi-noach
shlomi-noach requested changes Feb 21, 2023
View reviewed changes
Copy link
Contributor

@shlomi-noach shlomi-noach left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Very thorough! I have one request for change, see lag throttler. Otherwise this looks good

go/vt/vtgate/buffer/buffer_helper_test.go Outdated
Copy link
Contributor

@shlomi-noach shlomi-noach Feb 21, 2023

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I'm not even sure what the old code means; the semaphore acts both as an atomic primitive and indicates the size?

Copy link
Member Author

@dbussink dbussink Feb 21, 2023

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

We had code that indeed checked this size but the x/sync Go semaphore doesn't expose that (as it's a total weight, not a real size).

That's why this had to be added as a separate field. Agreed it's a bit wonky but I didn't want to go and change behavior here.

go/vt/vttablet/tabletmanager/vdiff/engine.go Outdated
Copy link
Contributor

@shlomi-noach shlomi-noach Feb 21, 2023

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

nice

frouioui
frouioui approved these changes Feb 21, 2023
View reviewed changes
Copy link
Member

@frouioui frouioui left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Thank you @dbussink 🙏🏻

vmg
vmg approved these changes Feb 21, 2023
View reviewed changes
Copy link
Collaborator

@vmg vmg left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

LGTM. There's a pice of @shlomi-noach's feedback you haven't addressed yet btw

@dbussink
Move to Go 1.19 atomics
1219ce3 
This change moves to Go 1.19 atomics in favor of the version we had in
the `sync2` package. The version in that package predates the
availability of the new atomics, but for the future we want to use the
Go provided ones.

On top of that, we can also use the semaphore from `x/sync` instead of a
custom one in `sync2`. This cleans up a bunch of additional code from
`sync2`.

Signed-off-by: Dirkjan Bussink <d.bussink@gmail.com>
@dbussink
Don't assume the value is a duration
1805981 
This can be any float, so we need to store the float bits in an atomic
uint64 instead (as Go has no atomic floats).

Signed-off-by: Dirkjan Bussink <d.bussink@gmail.com>
@dbussink
Log actual error if acquiring semaphore fails
5edb96d 
Signed-off-by: Dirkjan Bussink <d.bussink@gmail.com>
@dbussink
Fix overlooked metrics threshold case
ab6bda5 
Signed-off-by: Dirkjan Bussink <d.bussink@gmail.com>
@dbussink dbussink merged commit a7300c9 into vitessio:main Feb 21, 2023
@dbussink dbussink deleted the use-stdlib-atomics branch February 21, 2023 12:59
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

@vmg vmg vmg approved these changes

@shlomi-noach shlomi-noach shlomi-noach approved these changes

@frouioui frouioui frouioui approved these changes

@deepthi deepthi Awaiting requested review from deepthi

@mattlord mattlord Awaiting requested review from mattlord mattlord is a code owner

@rohit-nayak-ps rohit-nayak-ps Awaiting requested review from rohit-nayak-ps rohit-nayak-ps is a code owner

@ajm188 ajm188 Awaiting requested review from ajm188

@GuptaManan100 GuptaManan100 Awaiting requested review from GuptaManan100

@rsajwani rsajwani Awaiting requested review from rsajwani

@derekperkins derekperkins Awaiting requested review from derekperkins derekperkins is a code owner

@harshit-gangal harshit-gangal Awaiting requested review from harshit-gangal harshit-gangal is a code owner

@systay systay Awaiting requested review from systay systay is a code owner

@notfelineit notfelineit Awaiting requested review from notfelineit

Assignees

No one assigned

Labels

Component: General Changes throughout the code base Type: Internal Cleanup

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

Move to Go 1.19 atomics

4 participants

@dbussink @vmg @shlomi-noach @frouioui