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

Don't use exchange in the hot path of the GC #50021

Merged
merged 3 commits into from
Jun 8, 2023
Merged

Don't use exchange in the hot path of the GC #50021

Changes from 2 commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
36ce0ee
Don't use exchange in the hot path of the GC
gbaraldi May 31, 2023
6fbdf3d
Save one extra load
gbaraldi Jun 1, 2023
267b3d6
Return a constant
gbaraldi Jun 1, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
9 changes: 5 additions & 4 deletions src/gc.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -804,7 +804,8 @@ STATIC_INLINE void gc_queue_big_marked(jl_ptls_t ptls, bigval_t *hdr,
FORCE_INLINE int gc_try_setmark_tag(jl_taggedvalue_t *o, uint8_t mark_mode) JL_NOTSAFEPOINT
{
assert(gc_marked(mark_mode));
uintptr_t tag = o->header;
uintptr_t tag = jl_atomic_load_relaxed((_Atomic(uintptr_t)*)&o->header);
uintptr_t curr = tag;
if (gc_marked(tag))
return 0;
if (mark_reset_age) {
Expand All @@ -818,9 +819,9 @@ FORCE_INLINE int gc_try_setmark_tag(jl_taggedvalue_t *o, uint8_t mark_mode) JL_N
tag = tag | mark_mode;
assert((tag & 0x3) == mark_mode);
}
tag = jl_atomic_exchange_relaxed((_Atomic(uintptr_t)*)&o->header, tag);
verify_val(jl_valueof(o));
return !gc_marked(tag);
jl_atomic_store_relaxed((_Atomic(uintptr_t)*)&o->header, tag); //xchg here was slower than
verify_val(jl_valueof(o)); //potentially redoing work because of a stale tag.
return !gc_marked(curr);
gbaraldi marked this conversation as resolved.
Show resolved Hide resolved
}

// This function should be called exactly once during marking for each big
Expand Down