diff options
author | Kevin Newton <kddnewton@gmail.com> | 2021-11-24 10:31:23 -0500 |
---|---|---|
committer | Aaron Patterson <aaron.patterson@gmail.com> | 2022-03-24 09:14:38 -0700 |
commit | 629908586b4bead1103267652f8b96b1083573a8 (patch) | |
tree | c2d53b1ae8b86571256f290851d95d6af4ba73db /internal/vm.h | |
parent | 5f10bd634fb6ae8f74a4ea730176233b0ca96954 (diff) |
Finer-grained inline constant cache invalidation
Current behavior - caches depend on a global counter. All constant mutations cause caches to be invalidated.
```ruby
class A
B = 1
end
def foo
A::B # inline cache depends on global counter
end
foo # populate inline cache
foo # hit inline cache
C = 1 # global counter increments, all caches are invalidated
foo # misses inline cache due to `C = 1`
```
Proposed behavior - caches depend on name components. Only constant mutations with corresponding names will invalidate the cache.
```ruby
class A
B = 1
end
def foo
A::B # inline cache depends constants named "A" and "B"
end
foo # populate inline cache
foo # hit inline cache
C = 1 # caches that depend on the name "C" are invalidated
foo # hits inline cache because IC only depends on "A" and "B"
```
Examples of breaking the new cache:
```ruby
module C
# Breaks `foo` cache because "A" constant is set and the cache in foo depends
# on "A" and "B"
class A; end
end
B = 1
```
We expect the new cache scheme to be invalidated less often because names aren't frequently reused. With the cache being invalidated less, we can rely on its stability more to keep our constant references fast and reduce the need to throw away generated code in YJIT.
Notes
Notes:
Merged: https://github.com/ruby/ruby/pull/5433
Diffstat (limited to 'internal/vm.h')
-rw-r--r-- | internal/vm.h | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/internal/vm.h b/internal/vm.h index b14d5472c4..c6c6b2ccc2 100644 --- a/internal/vm.h +++ b/internal/vm.h @@ -47,7 +47,6 @@ VALUE rb_obj_is_thread(VALUE obj); void rb_vm_mark(void *ptr); void rb_vm_each_stack_value(void *ptr, void (*cb)(VALUE, void*), void *ctx); PUREFUNC(VALUE rb_vm_top_self(void)); -void rb_vm_inc_const_missing_count(void); const void **rb_vm_get_insns_address_table(void); VALUE rb_source_location(int *pline); const char *rb_source_location_cstr(int *pline); |