Skip to content

Refine specialization caches and extend binary-op coverage #7386

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

Merged
youknowone merged 14 commits into from
Mar 10, 2026
Merged

Refine specialization caches and extend binary-op coverage #7386

Changes from 1 commit
Commits
Show all changes
14 commits
Select commit Hold shift + click to select a range
5393e86
Align BINARY_OP_EXTEND with CPython descriptor cache model
youknowone Mar 8, 2026
5bc6078
Align type _spec_cache and latin1 singleton string paths
youknowone Mar 8, 2026
cb156c1
Add specialization differential harness and align init error text
youknowone Mar 8, 2026
fc4728b
Tighten CALL_ALLOC_AND_ENTER_INIT stack-space guard
youknowone Mar 8, 2026
c487b6d
Align call-init frame flow and spec cache atomic ordering
youknowone Mar 8, 2026
2dd64b8
Refine call-init recursion guard and cache swap lifetime handling
youknowone Mar 8, 2026
a0c302c
Align spec cache write locking with CPython contract
youknowone Mar 8, 2026
ceefe6e
rename
youknowone Mar 8, 2026
2d7cb74
address review: invalidate init cache on type modification, add cspel…
youknowone Mar 8, 2026
f7924dd
Align load attr miss cooldown with CPython
youknowone Mar 8, 2026
138d48e
Align CALL descriptor and class-call specialization with CPython
youknowone Mar 8, 2026
aa9f5a8
address review: check datastack space for extra_bytes, require CO_OPT…
youknowone Mar 8, 2026
a277b86
Extract datastack_frame_size_bytes_for_code, skip monitoring for init…
youknowone Mar 9, 2026
dbd8b1a
Fix Constants newtype usage in init_cleanup_code
youknowone Mar 9, 2026
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
Prev Previous commit
Next Next commit
Align load attr miss cooldown with CPython
  • Loading branch information
@youknowone
youknowone committed Mar 10, 2026
commit f7924ddf38f487d093900b1b816c3e36adc48802
86 changes: 53 additions & 33 deletions crates/vm/src/frame.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -7357,19 +7357,38 @@ impl ExecutingFrame<'_> {
return;
}

// Module attribute access: use LoadAttrModule
if obj.downcast_ref_if_exact::<PyModule>(_vm).is_some() {
unsafe {
self.code
.instructions
.write_cache_u32(cache_base + 1, type_version);
let attr_name = self.code.names[oparg.name_idx() as usize];

// Match CPython: only specialize module attribute loads when the
// current module dict has no __getattr__ override and the attribute is
// already present.
if let Some(module) = obj.downcast_ref_if_exact::<PyModule>(_vm) {
let module_dict = module.dict();
match (
module_dict.get_item_opt(identifier!(_vm, __getattr__), _vm),
module_dict.get_item_opt(attr_name, _vm),
) {
(Ok(None), Ok(Some(_))) => {
unsafe {
self.code
.instructions
.write_cache_u32(cache_base + 1, type_version);
}
self.specialize_at(instr_idx, cache_base, Instruction::LoadAttrModule);
}
Comment thread
coderabbitai[bot] marked this conversation as resolved.
(Ok(_), Ok(_)) => self.cooldown_adaptive_at(cache_base),
_ => unsafe {
self.code.instructions.write_adaptive_counter(
cache_base,
bytecode::adaptive_counter_backoff(
self.code.instructions.read_adaptive_counter(cache_base),
),
);
},
}
self.specialize_at(instr_idx, cache_base, Instruction::LoadAttrModule);
return;
}

let attr_name = self.code.names[oparg.name_idx() as usize];

// Look up attr in class via MRO
let cls_attr = cls.get_attr(attr_name);
let class_has_dict = cls.slots.flags.has_feature(PyTypeFlags::HAS_DICT);
Expand Down Expand Up @@ -7479,8 +7498,11 @@ impl ExecutingFrame<'_> {
Instruction::LoadAttrNondescriptorWithValues,
);
} else {
// No class attr, must be in instance dict
let use_hint = if let Some(dict) = obj.dict() {
// Match CPython ABSENT/no-shadow behavior: if the
// attribute is missing on both the class and the current
// instance, keep the generic opcode and just enter
// cooldown instead of specializing a repeated miss path.
let has_instance_attr = if let Some(dict) = obj.dict() {
match dict.get_item_opt(attr_name, _vm) {
Ok(Some(_)) => true,
Ok(None) => false,
Expand All @@ -7501,20 +7523,16 @@ impl ExecutingFrame<'_> {
} else {
false
};
unsafe {
self.code
.instructions
.write_cache_u32(cache_base + 1, type_version);
if has_instance_attr {
unsafe {
self.code
.instructions
.write_cache_u32(cache_base + 1, type_version);
}
self.specialize_at(instr_idx, cache_base, Instruction::LoadAttrWithHint);
} else {
self.cooldown_adaptive_at(cache_base);
}
self.specialize_at(
instr_idx,
cache_base,
if use_hint {
Instruction::LoadAttrWithHint
} else {
Instruction::LoadAttrInstanceValue
},
);
}
} else if let Some(ref descr) = cls_attr {
// No dict support, plain class attr — cache directly
Expand All @@ -7528,15 +7546,8 @@ impl ExecutingFrame<'_> {
Instruction::LoadAttrNondescriptorNoDict,
);
} else {
// No dict, no class attr — can't specialize
unsafe {
self.code.instructions.write_adaptive_counter(
cache_base,
bytecode::adaptive_counter_backoff(
self.code.instructions.read_adaptive_counter(cache_base),
),
);
}
// No dict and no class attr: repeated miss path, so cooldown.
self.cooldown_adaptive_at(cache_base);
}
}
}
Expand Down Expand Up @@ -7932,6 +7943,15 @@ impl ExecutingFrame<'_> {
}
}

#[inline]
fn cooldown_adaptive_at(&mut self, cache_base: usize) {
unsafe {
self.code
.instructions
.write_adaptive_counter(cache_base, ADAPTIVE_COOLDOWN_VALUE);
}
}

/// Commit a specialization result: replace op on success, backoff on failure.
#[inline]
fn commit_specialization(
Expand Down