Copyright	(C) 2026 Edward Kmett
License	UPL-1.0 AND BSD-3-Clause
Maintainer	Edward Kmett <ekmett@gmail.com>
Stability	experimental
Portability	GHC FFI; THC runtime services or native fallback implementation
Safe Haskell	Trustworthy
Language	Haskell2010

THC.Memory

Description

Read-only memory accounting. A record contains independently sampled fields, not an atomic snapshot. All sizes are bytes.

Synopsis

data Available a
- = Available a
- | Unsupported
- | Disabled
- | Denied
- | Unavailable
data MemoryUsage = MemoryUsage {
- usedBytes :: Available Word64
- committedBytes :: Available Word64
- maximumBytes :: Available Word64
- initialBytes :: Available Word64
}
data NativeAllocationUsage = NativeAllocationUsage {
- nativeRequestedBytes :: Available Word64
- nativeAllocationCount :: Available Word64
}
heapUsage :: IO MemoryUsage
nonHeapUsage :: IO MemoryUsage
nativeAllocationUsage :: IO NativeAllocationUsage

Documentation

data Available a Source #

An absent metric is not zero. Queries never enable JVM-wide monitoring. fmap transforms a genuine value and preserves every non-value status:

>>> fmap (+ 1) (Available (41 :: Int))
Available 42
>>> fmap (+ 1) (Disabled :: Available Int)
Disabled
>>> map (fmap (+ 1)) [Unsupported, Disabled, Denied, Unavailable :: Available Int]
[Unsupported,Disabled,Denied,Unavailable]

Constructors

Available a	A genuine value; its scope is specified by the query.
Unsupported	The runtime or provider does not implement this service.
Disabled	Supported, but its instrumentation or sink is switched off.
Denied	The current context or host security policy forbids access.
Unavailable	Normally supported, but no value is currently available.

Instances

Instances details

Functor Available #
Instance details Defined in THC.Runtime.Types Methods fmap :: (a -> b) -> Available a -> Available b # (<$) :: a -> Available b -> Available a #
Eq a => Eq (Available a) #
Instance details Defined in THC.Runtime.Types Methods (==) :: Available a -> Available a -> Bool # (/=) :: Available a -> Available a -> Bool #
Ord a => Ord (Available a) #
Instance details Defined in THC.Runtime.Types Methods compare :: Available a -> Available a -> Ordering # (<) :: Available a -> Available a -> Bool # (<=) :: Available a -> Available a -> Bool # (>) :: Available a -> Available a -> Bool # (>=) :: Available a -> Available a -> Bool # max :: Available a -> Available a -> Available a # min :: Available a -> Available a -> Available a #
Show a => Show (Available a) #
Instance details Defined in THC.Runtime.Types Methods showsPrec :: Int -> Available a -> ShowS # show :: Available a -> String # showList :: [Available a] -> ShowS #

data MemoryUsage Source #

JVM-wide usage. Unknown maximum/initial sizes are Unavailable, not zero.

Constructors

MemoryUsage
Fields usedBytes :: Available Word64 committedBytes :: Available Word64 maximumBytes :: Available Word64 initialBytes :: Available Word64

Instances

Instances details

Eq MemoryUsage #
Instance details Defined in THC.Memory Methods (==) :: MemoryUsage -> MemoryUsage -> Bool # (/=) :: MemoryUsage -> MemoryUsage -> Bool #
Show MemoryUsage #
Instance details Defined in THC.Memory Methods showsPrec :: Int -> MemoryUsage -> ShowS # show :: MemoryUsage -> String # showList :: [MemoryUsage] -> ShowS #

data NativeAllocationUsage Source #

Only live allocations owned by the current THC context's libc allocator. Counts requested bytes; excludes other SulongnativeJVM/pinned allocations and allocator overhead. Includes allocations awaiting outstanding borrowers before release. This is not process RSS or total native memory.

Constructors

NativeAllocationUsage
Fields nativeRequestedBytes :: Available Word64 nativeAllocationCount :: Available Word64

Instances

Instances details

Eq NativeAllocationUsage #
Instance details Defined in THC.Memory Methods (==) :: NativeAllocationUsage -> NativeAllocationUsage -> Bool # (/=) :: NativeAllocationUsage -> NativeAllocationUsage -> Bool #
Show NativeAllocationUsage #
Instance details Defined in THC.Memory Methods showsPrec :: Int -> NativeAllocationUsage -> ShowS # show :: NativeAllocationUsage -> String # showList :: [NativeAllocationUsage] -> ShowS #

heapUsage :: IO MemoryUsage Source #

Sample JVM heap usage. Unsupported or unknown quantities keep their status rather than becoming zero; this does not trigger garbage collection.

nonHeapUsage :: IO MemoryUsage Source #

Sample JVM non-heap usage, with the same per-field status contract as heapUsage. This is not the context's native-allocation accounting.

nativeAllocationUsage :: IO NativeAllocationUsage Source #

Sample live requested bytes and allocation count for the current context's libc allocator. See NativeAllocationUsage for the accounting exclusions.