Make the Julia GC threadsafe when used from GAP.jl #4071
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
When running from multi-threaded Julia, we have to consider the case that GAP can be called from more than one thread. In those cases, the variable JuliaTLS may be incorrect. We therefore update it in NewBag(), where it is depended upon for allocations. It had already been set when a GC was called from a separate thread. In order to avoid unnecessary overhead in the single-threaded case, we do not change JuliaTLS for allocations when there is only one thread, as determining the current thread-local state pointer can be somewhat costly (which is why we cache it in JuliaTLS in the first place).
fingolfin
added
topic: julia
fingolfin
approved these changes
Jul 10, 2020
src/julia_gc.c
Outdated
| @@ -199,11 +199,17 @@ static jl_datatype_t * datatype_largebag; | |||
| static UInt StackAlignBags; | |||
| static Bag * GapStackBottom; | |||
| static jl_ptls_t JuliaTLS, SaveTLS; | |||
| static int is_threaded; | |||
There was a problem hiding this comment.
Suggested change
| static int is_threaded; | |
| static BOOL is_threaded; |
rbehrends
force-pushed
the
gap-jl-threadsafe
branch
from
139db67
to
4468a50
Compare
|
Backported to stable-4.11 in 27ebdf9 |
PaulaHaehndel
added
the
release notes: added
PaulaHaehndel
changed the title
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
When running from multi-threaded Julia, we have to consider the case
that GAP can be called from more than one thread. In those cases, the
variable JuliaTLS may be incorrect. We therefore update it in NewBag(),
where it is depended upon for allocations. It had already been set when
a GC was called from a separate thread.
In order to avoid unnecessary overhead in the single-threaded case, we
do not change JuliaTLS for allocations when there is only one thread, as
determining the current thread-local state pointer can be somewhat
costly (which is why we cache it in JuliaTLS in the first place).