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

implement syncscopes everywhere #20

Merged
merged 7 commits into from
Dec 10, 2024
+297 −352
Merged

implement syncscopes everywhere #20

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
7 commits
Select commit Hold shift + click to select a range
828833a
implement syncscopes everywhere
vchuravy Dec 2, 2024
84ec64e
Support syncscope in UnsafeAtomicsLLVM
vchuravy Dec 5, 2024
43d9bd4
fixup! Support syncscope in UnsafeAtomicsLLVM
vchuravy Dec 5, 2024
3ff51d2
add back old code
vchuravy Dec 5, 2024
f66264e
fixup! add back old code
vchuravy Dec 5, 2024
06675ab
fixup! fixup! add back old code
vchuravy Dec 5, 2024
95ff903
add some tests
vchuravy Dec 6, 2024
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
2 changes: 1 addition & 1 deletion Project.toml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,7 @@ LLVM = "929cbde3-209d-540e-8aea-75f648917ca0"
UnsafeAtomicsLLVM = ["LLVM"]

[compat]
LLVM = "8.1, 9"
LLVM = "9"
julia = "1.10"

[extras]
Expand Down
233 changes: 29 additions & 204 deletions ext/UnsafeAtomicsLLVM/atomics.jl
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -89,68 +89,12 @@ for (julia, llvm) in pairs(_llvm_from_julia_ordering)
@eval llvm_from_julia_ordering(::Val{$(QuoteNode(julia))}) = Val{$llvm}()
end

"""
@dynamic_order(order) do order
... use order ...
end
It is expanded to an expression similar to:
if order === :not_atomic
let order = Val(:not_atomic)
... use order ...
end
elseif order === :unordered
let order = Val(:unordered)
... use order ...
end
elseif ...
...
else
throw(ConcurrencyViolationError(...))
end
This is used for helping the compiler to optimize expressions such as
`atomic_pointerref(ptr, :monotonic)` and also to avoid abstract run-time dispatch.
"""
macro dynamic_order(thunk, order)
@assert Meta.isexpr(thunk, :->, 2) && Meta.isexpr(thunk.args[1], :tuple, 1)
ordervar = esc(thunk.args[1].args[1])
body = esc(thunk.args[2])
expr = foldr(
keys(_llvm_from_julia_ordering),
init = :(throw(ConcurrencyViolationError("invalid atomic ordering: ", order))),
) do key, r
quote
if order === $(QuoteNode(key))
let $ordervar = Val{$(QuoteNode(key))}()
$body
end
else
$r
end
end
end
quote
order = $(esc(order))
$expr
end
end

_valueof(::Val{x}) where {x} = x

@inline function atomic_pointerref(pointer, order::Symbol)
@dynamic_order(order) do order
atomic_pointerref(pointer, order)
end
end

@inline function atomic_pointerset(pointer, x, order::Symbol)
@dynamic_order(order) do order
atomic_pointerset(pointer, x, order)
end
end

@generated function atomic_pointerref(ptr::LLVMPtr{T,A}, order::AllOrdering) where {T,A}
@generated function atomic_pointerref(ptr::LLVMPtr{T,A}, order::AllOrdering, sync) where {T,A}
sizeof(T) == 0 && return T.instance
llvm_order = _valueof(llvm_from_julia_ordering(order()))
llvm_order = _valueof(llvm_from_julia_ordering(order()))
llvm_syncscope = _valueof(sync())
@dispose ctx = Context() begin
eltyp = convert(LLVMType, T)

Expand All @@ -170,6 +114,7 @@ end
typed_ptr = bitcast!(builder, parameters(llvm_f)[1], T_typed_ptr)
ld = load!(builder, eltyp, typed_ptr)
ordering!(ld, llvm_order)
syncscope!(ld, SyncScope(string(llvm_syncscope)))

if A != 0
metadata(ld)[LLVM.MD_tbaa] = tbaa_addrspace(A)
Expand All @@ -187,6 +132,7 @@ end
ptr::LLVMPtr{T,A},
x::T,
order::AllOrdering,
sync,
) where {T,A}
if sizeof(T) == 0
# Mimicking what `Core.Intrinsics.atomic_pointerset` generates.
Expand All @@ -197,7 +143,8 @@ end
return ptr
end
end
llvm_order = _valueof(llvm_from_julia_ordering(order()))
llvm_order = _valueof(llvm_from_julia_ordering(order()))
llvm_syncscope = _valueof(sync())
@dispose ctx = Context() begin
eltyp = convert(LLVMType, T)
T_ptr = convert(LLVMType, ptr)
Expand All @@ -216,6 +163,7 @@ end
val = parameters(llvm_f)[2]
st = store!(builder, val, typed_ptr)
ordering!(st, llvm_order)
syncscope!(st, SyncScope(string(llvm_syncscope)))

if A != 0
metadata(st)[LLVM.MD_tbaa] = tbaa_addrspace(A)
Expand Down Expand Up @@ -254,14 +202,12 @@ const binoptable = [

const AtomicRMWBinOpVal = Union{(Val{binop} for (_, _, binop) in binoptable)...}

# LLVM API accepts string literal as a syncscope argument.
@inline syncscope_to_string(::Type{Val{S}}) where {S} = string(S)

@generated function llvm_atomic_op(
binop::AtomicRMWBinOpVal,
ptr::LLVMPtr{T,A},
val::T,
order::LLVMOrderingVal,
sync,
) where {T,A}
@dispose ctx = Context() begin
T_val = convert(LLVMType, T)
Expand All @@ -270,21 +216,21 @@ const AtomicRMWBinOpVal = Union{(Val{binop} for (_, _, binop) in binoptable)...}
T_typed_ptr = LLVM.PointerType(T_val, A)

llvm_f, _ = create_function(T_val, [T_ptr, T_val])
llvm_syncscope = _valueof(sync())

@dispose builder = IRBuilder() begin
entry = BasicBlock(llvm_f, "entry")
position!(builder, entry)

typed_ptr = bitcast!(builder, parameters(llvm_f)[1], T_typed_ptr)

single_threaded = false
rv = atomic_rmw!(
builder,
_valueof(binop()),
typed_ptr,
parameters(llvm_f)[2],
_valueof(order()),
single_threaded,
SyncScope(string(llvm_syncscope))
)

ret!(builder, rv)
Expand All @@ -294,139 +240,40 @@ const AtomicRMWBinOpVal = Union{(Val{binop} for (_, _, binop) in binoptable)...}
end
end

@generated function llvm_atomic_op(
binop::AtomicRMWBinOpVal,
ptr::LLVMPtr{T,A},
val::T,
order::LLVMOrderingVal,
syncscope::Val{S},
) where {T,A,S}
@dispose ctx = Context() begin
T_val = convert(LLVMType, T)
T_ptr = convert(LLVMType, ptr)

T_typed_ptr = LLVM.PointerType(T_val, A)
llvm_f, _ = create_function(T_val, [T_ptr, T_val])

@dispose builder = IRBuilder() begin
entry = BasicBlock(llvm_f, "entry")
position!(builder, entry)

typed_ptr = bitcast!(builder, parameters(llvm_f)[1], T_typed_ptr)
rv = atomic_rmw!(
builder,
_valueof(binop()),
typed_ptr,
parameters(llvm_f)[2],
_valueof(order()),
syncscope_to_string(syncscope),
)

ret!(builder, rv)
end
call_function(llvm_f, T, Tuple{LLVMPtr{T,A},T}, :ptr, :val)
end
end

@inline function atomic_pointermodify(pointer, op::OP, x, order::Symbol) where {OP}
@dynamic_order(order) do order
atomic_pointermodify(pointer, op, x, order)
end
end

@inline function atomic_pointermodify(
ptr::LLVMPtr{T},
op,
x::T,
::Val{:not_atomic},
) where {T}
old = atomic_pointerref(ptr, Val(:not_atomic))
new = op(old, x)
atomic_pointerset(ptr, new, Val(:not_atomic))
return old => new
end

@inline function atomic_pointermodify(
ptr::LLVMPtr{T},
::typeof(right),
x::T,
order::AtomicOrdering,
) where {T}
sync::Val{S}
) where {T, S}
old = llvm_atomic_op(
Val(LLVM.API.LLVMAtomicRMWBinOpXchg),
ptr,
x,
llvm_from_julia_ordering(order),
sync
)
return old => x
end

const atomictypes = Any[
Int8,
Int16,
Int32,
Int64,
Int128,
UInt8,
UInt16,
UInt32,
UInt64,
UInt128,
Float16,
Float32,
Float64,
]

for (opname, op, llvmop) in binoptable
opname === :xchg && continue
types = if opname in (:min, :max)
filter(t -> t <: Signed, atomictypes)
elseif opname in (:umin, :umax)
filter(t -> t <: Unsigned, atomictypes)
elseif opname in (:fadd, :fsub, :fmin, :fmax)
filter(t -> t <: AbstractFloat, atomictypes)
else
filter(t -> t <: Integer, atomictypes)
end
for T in types
@eval @inline function atomic_pointermodify(
ptr::LLVMPtr{$T},
::$(typeof(op)),
x::$T,
order::AtomicOrdering,
syncscope::Val{S} = Val{:system}(),
) where {S}
old =
syncscope isa Val{:system} ?
llvm_atomic_op($(Val(llvmop)), ptr, x, llvm_from_julia_ordering(order)) :
llvm_atomic_op(
$(Val(llvmop)),
ptr,
x,
llvm_from_julia_ordering(order),
syncscope,
)
return old => $op(old, x)
end
end
end

@inline atomic_pointerswap(pointer, new) = first(atomic_pointermodify(pointer, right, new))
@inline atomic_pointerswap(pointer, new, order) =
first(atomic_pointermodify(pointer, right, new, order))
# @inline atomic_pointerswap(pointer, new) = first(atomic_pointermodify(pointer, right, new))
@inline atomic_pointerswap(pointer, new, order, sync) =
first(atomic_pointermodify(pointer, right, new, order, sync))

@inline function atomic_pointermodify(
ptr::LLVMPtr{T},
op,
x::T,
order::AllOrdering,
) where {T}
sync::S,
) where {T, S}
# Should `fail_order` be stronger? Ref: https://github.com/JuliaLang/julia/issues/45256
fail_order = Val(:monotonic)
old = atomic_pointerref(ptr, fail_order)
old = atomic_pointerref(ptr, fail_order, sync)
while true
new = op(old, x)
(old, success) = atomic_pointerreplace(ptr, old, new, order, fail_order)
(old, success) = atomic_pointerreplace(ptr, old, new, order, fail_order, sync)
success && return old => new
end
end
Expand All @@ -437,9 +284,11 @@ end
val::T,
success_order::LLVMOrderingVal,
fail_order::LLVMOrderingVal,
sync,
) where {T,A}
llvm_success = _valueof(success_order())
llvm_fail = _valueof(fail_order())
llvm_syncscope = _valueof(sync())
@dispose ctx = Context() begin
T_val = convert(LLVMType, T)
T_pointee = T_val
Expand Down Expand Up @@ -471,15 +320,14 @@ end
val_int = bitcast!(builder, val_int, T_pointee)
end

single_threaded = false
res = atomic_cmpxchg!(
builder,
typed_ptr,
cmp_int,
val_int,
llvm_success,
llvm_fail,
single_threaded,
SyncScope(string(llvm_syncscope)),
)

rv = extract_value!(builder, res, 0)
Expand Down Expand Up @@ -514,42 +362,17 @@ end
end
end

@inline function atomic_pointerreplace(
pointer,
expected,
desired,
success_order::Symbol,
fail_order::Symbol,
)
# This avoids abstract dispatch at run-time but probably too much codegen?
#=
@dynamic_order(success_order) do success_order
@dynamic_order(fail_order) do fail_order
atomic_pointerreplace(pointer, expected, desired, success_order, fail_order)
end
end
=#

# This avoids excessive codegen while hopefully imposes no cost when const-prop works:
so = @dynamic_order(success_order) do success_order
success_order
end
fo = @dynamic_order(fail_order) do fail_order
fail_order
end
return atomic_pointerreplace(pointer, expected, desired, so, fo)
end

@inline function atomic_pointerreplace(
ptr::LLVMPtr{T},
expected::T,
desired::T,
::Val{:not_atomic},
::Val{:not_atomic},
sync,
) where {T}
old = atomic_pointerref(ptr, Val(:not_atomic))
old = atomic_pointerref(ptr, Val(:not_atomic), sync)
if old === expected
atomic_pointerset(ptr, desired, Val(:not_atomic))
atomic_pointerset(ptr, desired, Val(:not_atomic), sync)
success = true
else
success = false
Expand All @@ -563,10 +386,12 @@ end
desired::T,
success_order::_julia_ordering(∉((:not_atomic, :unordered))),
fail_order::_julia_ordering(∉((:not_atomic, :unordered, :release, :acquire_release))),
sync
) where {T} = llvm_atomic_cas(
ptr,
expected,
desired,
llvm_from_julia_ordering(success_order),
llvm_from_julia_ordering(fail_order),
sync
)
Loading
Loading