Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Slowdown on GHC 9.4 when fixity-th configure flag is enabled #941

Closed
Gabriella439 opened this issue Nov 17, 2022 · 3 comments · Fixed by #954
Closed

Slowdown on GHC 9.4 when fixity-th configure flag is enabled #941

Gabriella439 opened this issue Nov 17, 2022 · 3 comments · Fixed by #954
Assignees
@mrkkrp
Labels
bug-upstream Something upstream is not working.

Comments

@Gabriella439
Copy link

Describe the bug

ormolu is significantly slower when formatting expressions that mix operators of different fixities if ormolu was built with fixity-th enabled (which is the default).

To Reproduce

To reproduce this behavior, build ormolu with the fixity-th flag enabled (which is the default) and then format the following file:

a = b =. c <$> d

This will take a while (≈ 43 seconds on my machine).

The problem disappears if you build ormolu without the fixity-th flag or if you build using GHC 9.2 or older. In those cases formatting speed goes back to normal (≈ 0.2 seconds).

Expected behavior

The performance with fixity-th shouldn't be significantly slower than without fixity-th. My understanding is that the fixity-th flag is supposed to be an optimization (to compile the fixity look-up table at compile-time using TemplateHaskell instead of decoding the look-up table at runtime) but in this case it's actually significantly less efficient due to some change introduced in GHC 9.4.

Environment
@MaxGabriel
Copy link

(I have also reproduced this on a regular Intel Mac, in case anyone is worried about the M1 running x86 causing weirdness)

@Gabriella439 Gabriella439 mentioned this issue Nov 17, 2022
Merged
13 tasks
Gabriella439 added a commit to MercuryTechnologies/nixpkgs that referenced this issue Nov 17, 2022
@Gabriella439
haskell.packages.ghc94.{or,four}molu: Disable fixity-th flag
524ddeb 
See: tweag/ormolu#941
@amesgen amesgen added the bug-upstream Something upstream is not working. label Nov 17, 2022
@amesgen
Copy link
Member

amesgen commented Nov 17, 2022

Interesting, thanks for the report! I can reproduce this on x86_64-linux using GHC 9.4.3 (and also on 9.4.2). The fixity-th flag seems to be a magnet for GHC bugs, cf. #927...

This was referenced Dec 10, 2022
Closed
Merged
@amesgen
Copy link
Member

amesgen commented Dec 10, 2022

PR to disable fixity-th on GHC 9.4 for the time being: #945

@mrkkrp mrkkrp self-assigned this Jan 3, 2023
mrkkrp added a commit that referenced this issue Jan 3, 2023
@mrkkrp
Eliminate the fixity-th cabal flag
36d02ba 
The flag caused problems on GHC 9.4 and generally was a magnet for bugs, see
#941 and
#927. We are going to try to use
file-embed unconditionally and make parsing more efficient instead.
@mrkkrp mrkkrp mentioned this issue Jan 3, 2023
Merged
mrkkrp added a commit that referenced this issue Jan 3, 2023
@mrkkrp
Eliminate the fixity-th cabal flag
a3d7d71 
The flag caused problems on GHC 9.4 and generally was a magnet for bugs, see
#941 and
#927. We are going to try to use
file-embed unconditionally and make parsing more efficient instead.
mrkkrp added a commit that referenced this issue Jan 3, 2023
@mrkkrp
Eliminate the fixity-th cabal flag
5a7898e 
The flag caused problems on GHC 9.4 and generally was a magnet for bugs, see
#941 and
#927. We are going to try to use
file-embed unconditionally and make parsing more efficient instead.
mrkkrp added a commit that referenced this issue Jan 3, 2023
@mrkkrp
Eliminate the fixity-th cabal flag
d498da8 
The flag caused problems on GHC 9.4 and generally was a magnet for bugs, see
#941 and
#927. We are going to try to use
file-embed unconditionally and make parsing more efficient instead.
mrkkrp added a commit that referenced this issue Jan 3, 2023
@mrkkrp
Eliminate the fixity-th cabal flag
374773a 
The flag caused problems on GHC 9.4 and generally was a magnet for bugs, see
#941 and
#927. We are going to try to use
file-embed unconditionally and make parsing more efficient instead.
mrkkrp added a commit that referenced this issue Jan 3, 2023
@mrkkrp @amesgen
Eliminate the fixity-th cabal flag
9f828e8 
The flag caused problems on GHC 9.4 and generally was a magnet for bugs, see
#941 and
#927. We are going to try to use
file-embed unconditionally and make parsing more efficient instead.

Co-authored-by: amesgen <alexander.esgen@tweag.io>
mrkkrp added a commit that referenced this issue Jan 3, 2023
@mrkkrp @amesgen
Eliminate the fixity-th cabal flag
b545930 
The flag caused problems on GHC 9.4 and generally was a magnet for bugs, see
#941 and
#927. We are going to try to use
file-embed unconditionally and make parsing more efficient instead.

Co-authored-by: amesgen <alexander.esgen@tweag.io>
j6carey pushed a commit to awakesecurity/nixpkgs that referenced this issue Sep 27, 2023
@Gabriella439 @j6carey
haskell.packages.ghc94.{or,four}molu: Disable fixity-th flag
fd1bf13 
See: tweag/ormolu#941
j6carey pushed a commit to awakesecurity/nixpkgs that referenced this issue Nov 10, 2023
@Gabriella439 @j6carey
haskell.packages.ghc94.{or,four}molu: Disable fixity-th flag
c7e5eb2 
See: tweag/ormolu#941
jsoo1 pushed a commit to awakesecurity/nixpkgs that referenced this issue Nov 13, 2023
@Gabriella439 @jsoo1
haskell.packages.ghc94.{or,four}molu: Disable fixity-th flag
35d28a1 
See: tweag/ormolu#941
j6carey pushed a commit to awakesecurity/nixpkgs that referenced this issue Dec 17, 2023
@Gabriella439 @j6carey
haskell.packages.ghc94.{or,four}molu: Disable fixity-th flag
0f9ca6d 
See: tweag/ormolu#941
jsoo1 pushed a commit to awakesecurity/nixpkgs that referenced this issue Dec 19, 2023
@Gabriella439 @jsoo1
haskell.packages.ghc94.{or,four}molu: Disable fixity-th flag
c9c63f4 
See: tweag/ormolu#941
jsoo1 pushed a commit to awakesecurity/nixpkgs that referenced this issue Dec 20, 2023
@Gabriella439 @jsoo1
haskell.packages.ghc94.{or,four}molu: Disable fixity-th flag
174763e 
See: tweag/ormolu#941
jsoo1 pushed a commit to awakesecurity/nixpkgs that referenced this issue Dec 22, 2023
@Gabriella439 @jsoo1
haskell.packages.ghc94.{or,four}molu: Disable fixity-th flag
26778e3 
See: tweag/ormolu#941
jsoo1 pushed a commit to awakesecurity/nixpkgs that referenced this issue Jan 13, 2024
@Gabriella439 @jsoo1
haskell.packages.ghc94.{or,four}molu: Disable fixity-th flag
fbb2af2 
See: tweag/ormolu#941
tm-drtina pushed a commit to awakesecurity/nixpkgs that referenced this issue Feb 27, 2024
@Gabriella439 @tm-drtina
haskell.packages.ghc94.{or,four}molu: Disable fixity-th flag
9b61978 
See: tweag/ormolu#941
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Assignees

@mrkkrp mrkkrp

Labels
bug-upstream Something upstream is not working.
Projects
None yet
Milestone
No milestone
Development

Successfully merging a pull request may close this issue.

Eliminate the fixity-th cabal flag tweag/ormolu
4 participants
@MaxGabriel @Gabriella439 @mrkkrp @amesgen