Skip to content

GitLab

  • Projects
  • Groups
  • Snippets
  • Help
    • Loading...
  • Help
    • Help
    • Support
    • Community forum
    • Submit feedback
  • Sign in / Register
GHC
GHC
  • Project overview
    • Project overview
    • Details
    • Activity
    • Releases
  • Repository
    • Repository
    • Files
    • Commits
    • Branches
    • Tags
    • Contributors
    • Graph
    • Compare
    • Locked Files
  • Issues 4,320
    • Issues 4,320
    • List
    • Boards
    • Labels
    • Service Desk
    • Milestones
    • Iterations
  • Merge Requests 355
    • Merge Requests 355
  • Requirements
    • Requirements
    • List
  • CI / CD
    • CI / CD
    • Pipelines
    • Jobs
    • Schedules
  • Security & Compliance
    • Security & Compliance
    • Dependency List
    • License Compliance
  • Operations
    • Operations
    • Incidents
    • Environments
  • Analytics
    • Analytics
    • CI / CD
    • Code Review
    • Insights
    • Issue
    • Repository
    • Value Stream
  • Wiki
    • Wiki
  • Snippets
    • Snippets
  • Members
    • Members
  • Collapse sidebar
  • Activity
  • Graph
  • Create a new issue
  • Jobs
  • Commits
  • Issue Boards
  • Glasgow Haskell Compiler
  • GHCGHC
  • Issues
  • #2028

Closed
Open
Opened Jan 09, 2008 by JulesBean@trac-JulesBean

STM slightly conservative on write-only transactions

The STM appears to be slightly too conservative on write-only transactions.

It will store a copy of the current (that is, old) value on a writeTVar, even if it was never read from. This can cause a spurious retry.

E.g. atomically $ writeTVar tv 0 really has no reason to ever retry. Neither, in fact, does atomically $ mapM (\tv -> writeTVar tv 0) [tv1,tv2,tv3,tv4].

My suggestion is to instead indicate "no prior value" for that TVar, and then make no consistency checks on TVars marked as no prior value...

Jules

Trac metadata
Trac field Value
Version 6.8.1
Type Bug
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system Unknown
Architecture Unknown
Assignee
Assign to
8.0.1
Milestone
8.0.1 (Past due)
Assign milestone
Time tracking
None
Due date
None
Reference: ghc/ghc#2028