Modulebase-4.20.2.0Haskell2010

GHC.Stats

This module provides access to internal garbage collection and memory usage statistics. These statistics are not available unless a program is run with the -T RTS flag.

The API of this module is unstable and is tightly coupled to GHC's internals. If depend on it, make sure to use a tight upper bound, e.g., base < 4.X rather than base < 5, because the interface can change rapidly without much warning.

3 types
2 values

Packagebase-4.20.2.0
Exports5
LanguageHaskell2010
LicenceBSD-3-Clause
SourceStats.hs

Runtime statistics

5 declarations

datadata RTSStats

Statistics about runtime activity since the start of the program. This is a mirror of the C struct RTSStats in RtsAPI.h

Constructors

RTSStats
- gcs :: Word32
  Total number of GCs
- major_gcs :: Word32
  Total number of major (oldest generation) GCs
- allocated_bytes :: Word64
  Total bytes allocated
- max_live_bytes :: Word64
  Maximum live data (including large objects + compact regions) in the heap. Updated after a major GC.
- max_large_objects_bytes :: Word64
  Maximum live data in large objects
- max_compact_bytes :: Word64
  Maximum live data in compact regions
- max_slop_bytes :: Word64
  Maximum slop
- max_mem_in_use_bytes :: Word64
  Maximum memory in use by the RTS
- cumulative_live_bytes :: Word64
  Sum of live bytes across all major GCs. Divided by major_gcs gives the average live data over the lifetime of the program.
- copied_bytes :: Word64
  Sum of copied_bytes across all GCs
- par_copied_bytes :: Word64
  Sum of copied_bytes across all parallel GCs
- cumulative_par_max_copied_bytes :: Word64
  Sum of par_max_copied_bytes across all parallel GCs. Deprecated.
- cumulative_par_balanced_copied_bytes :: Word64
  Sum of par_balanced_copied bytes across all parallel GCs
- init_cpu_ns :: RtsTime
  Total CPU time used by the init phase @since base-4.12.0.0
- init_elapsed_ns :: RtsTime
  Total elapsed time used by the init phase @since base-4.12.0.0
- mutator_cpu_ns :: RtsTime
  Total CPU time used by the mutator
- mutator_elapsed_ns :: RtsTime
  Total elapsed time used by the mutator
- gc_cpu_ns :: RtsTime
  Total CPU time used by the GC
- gc_elapsed_ns :: RtsTime
  Total elapsed time used by the GC
- cpu_ns :: RtsTime
  Total CPU time (at the previous GC)
- elapsed_ns :: RtsTime
  Total elapsed time (at the previous GC)
- nonmoving_gc_sync_cpu_ns :: RtsTime
  The total CPU time used during the post-mark pause phase of the concurrent nonmoving GC.
- nonmoving_gc_sync_elapsed_ns :: RtsTime
  The total time elapsed during the post-mark pause phase of the concurrent nonmoving GC.
- nonmoving_gc_sync_max_elapsed_ns :: RtsTime
  The maximum elapsed length of any post-mark pause phase of the concurrent nonmoving GC.
- nonmoving_gc_cpu_ns :: RtsTime
  The total CPU time used by the nonmoving GC.
- nonmoving_gc_elapsed_ns :: RtsTime
  The total time elapsed during which there is a nonmoving GC active.
- nonmoving_gc_max_elapsed_ns :: RtsTime
  The maximum time elapsed during any nonmoving GC cycle.
- gc :: GCDetails
  Details about the most recent GC

Instances4Read, Show, Generic, Rep

Read RTSStatsDefined in ghc-internal-9.1003.0 · GHC.Internal.Stats
Show RTSStatsDefined in ghc-internal-9.1003.0 · GHC.Internal.Stats
Generic RTSStatsDefined in ghc-internal-9.1003.0 · GHC.Internal.Stats
type Rep RTSStats = D1 ('MetaData "RTSStats" "GHC.Internal.Stats" "ghc-internal" 'False) (C1 ('MetaCons "RTSStats" 'PrefixI 'True) ((((S1 ('MetaSel ('Just "gcs") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word32) :*: (S1 ('MetaSel ('Just "major_gcs") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word32) :*: S1 ('MetaSel ('Just "allocated_bytes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word64))) :*: ((S1 ('MetaSel ('Just "max_live_bytes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word64) :*: S1 ('MetaSel ('Just "max_large_objects_bytes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word64)) :*: (S1 ('MetaSel ('Just "max_compact_bytes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word64) :*: S1 ('MetaSel ('Just "max_slop_bytes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word64)))) :*: ((S1 ('MetaSel ('Just "max_mem_in_use_bytes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word64) :*: (S1 ('MetaSel ('Just "cumulative_live_bytes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word64) :*: S1 ('MetaSel ('Just "copied_bytes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word64))) :*: ((S1 ('MetaSel ('Just "par_copied_bytes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word64) :*: S1 ('MetaSel ('Just "cumulative_par_max_copied_bytes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word64)) :*: (S1 ('MetaSel ('Just "cumulative_par_balanced_copied_bytes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word64) :*: S1 ('MetaSel ('Just "init_cpu_ns") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 RtsTime))))) :*: (((S1 ('MetaSel ('Just "init_elapsed_ns") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 RtsTime) :*: (S1 ('MetaSel ('Just "mutator_cpu_ns") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 RtsTime) :*: S1 ('MetaSel ('Just "mutator_elapsed_ns") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 RtsTime))) :*: ((S1 ('MetaSel ('Just "gc_cpu_ns") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 RtsTime) :*: S1 ('MetaSel ('Just "gc_elapsed_ns") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 RtsTime)) :*: (S1 ('MetaSel ('Just "cpu_ns") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 RtsTime) :*: S1 ('MetaSel ('Just "elapsed_ns") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 RtsTime)))) :*: ((S1 ('MetaSel ('Just "nonmoving_gc_sync_cpu_ns") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 RtsTime) :*: (S1 ('MetaSel ('Just "nonmoving_gc_sync_elapsed_ns") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 RtsTime) :*: S1 ('MetaSel ('Just "nonmoving_gc_sync_max_elapsed_ns") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 RtsTime))) :*: ((S1 ('MetaSel ('Just "nonmoving_gc_cpu_ns") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 RtsTime) :*: S1 ('MetaSel ('Just "nonmoving_gc_elapsed_ns") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 RtsTime)) :*: (S1 ('MetaSel ('Just "nonmoving_gc_max_elapsed_ns") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 RtsTime) :*: S1 ('MetaSel ('Just "gc") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 GCDetails)))))))Defined in ghc-internal-9.1003.0 · GHC.Internal.Stats

datadata GCDetails

Statistics about a single GC. This is a mirror of the C struct GCDetails in RtsAPI.h, with the field prefixed with gc_ to avoid collisions with RTSStats.

Constructors

GCDetails
- gcdetails_gen :: Word32
  The generation number of this GC
- gcdetails_threads :: Word32
  Number of threads used in this GC
- gcdetails_allocated_bytes :: Word64
  Number of bytes allocated since the previous GC
- gcdetails_live_bytes :: Word64
  Total amount of live data in the heap (includes large + compact data). Updated after every GC. Data in uncollected generations (in minor GCs) are considered live.
- gcdetails_large_objects_bytes :: Word64
  Total amount of live data in large objects
- gcdetails_compact_bytes :: Word64
  Total amount of live data in compact regions
- gcdetails_slop_bytes :: Word64
  Total amount of slop (wasted memory)
- gcdetails_mem_in_use_bytes :: Word64
  Total amount of memory in use by the RTS
- gcdetails_copied_bytes :: Word64
  Total amount of data copied during this GC
- gcdetails_par_max_copied_bytes :: Word64
  In parallel GC, the max amount of data copied by any one thread. Deprecated.
- gcdetails_par_balanced_copied_bytes :: Word64
  In parallel GC, the amount of balanced data copied by all threads
- gcdetails_block_fragmentation_bytes :: Word64
  The amount of memory lost due to block fragmentation in bytes. Block fragmentation is the difference between the amount of blocks retained by the RTS and the blocks that are in use. This occurs when megablocks are only sparsely used, eg, when data that cannot be moved retains a megablock.
- gcdetails_sync_elapsed_ns :: RtsTime
  The time elapsed during synchronisation before GC
- gcdetails_cpu_ns :: RtsTime
  The CPU time used during GC itself
- gcdetails_elapsed_ns :: RtsTime
  The time elapsed during GC itself
- gcdetails_nonmoving_gc_sync_cpu_ns :: RtsTime
  The CPU time used during the post-mark pause phase of the concurrent nonmoving GC.
- gcdetails_nonmoving_gc_sync_elapsed_ns :: RtsTime
  The time elapsed during the post-mark pause phase of the concurrent nonmoving GC.

Instances4Read, Show, Generic, Rep

Read GCDetailsDefined in ghc-internal-9.1003.0 · GHC.Internal.Stats
Show GCDetailsDefined in ghc-internal-9.1003.0 · GHC.Internal.Stats
Generic GCDetailsDefined in ghc-internal-9.1003.0 · GHC.Internal.Stats
type Rep GCDetails = D1 ('MetaData "GCDetails" "GHC.Internal.Stats" "ghc-internal" 'False) (C1 ('MetaCons "GCDetails" 'PrefixI 'True) ((((S1 ('MetaSel ('Just "gcdetails_gen") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word32) :*: S1 ('MetaSel ('Just "gcdetails_threads") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word32)) :*: (S1 ('MetaSel ('Just "gcdetails_allocated_bytes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word64) :*: S1 ('MetaSel ('Just "gcdetails_live_bytes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word64))) :*: ((S1 ('MetaSel ('Just "gcdetails_large_objects_bytes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word64) :*: S1 ('MetaSel ('Just "gcdetails_compact_bytes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word64)) :*: (S1 ('MetaSel ('Just "gcdetails_slop_bytes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word64) :*: S1 ('MetaSel ('Just "gcdetails_mem_in_use_bytes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word64)))) :*: (((S1 ('MetaSel ('Just "gcdetails_copied_bytes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word64) :*: S1 ('MetaSel ('Just "gcdetails_par_max_copied_bytes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word64)) :*: (S1 ('MetaSel ('Just "gcdetails_par_balanced_copied_bytes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word64) :*: S1 ('MetaSel ('Just "gcdetails_block_fragmentation_bytes") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Word64))) :*: ((S1 ('MetaSel ('Just "gcdetails_sync_elapsed_ns") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 RtsTime) :*: S1 ('MetaSel ('Just "gcdetails_cpu_ns") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 RtsTime)) :*: (S1 ('MetaSel ('Just "gcdetails_elapsed_ns") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 RtsTime) :*: (S1 ('MetaSel ('Just "gcdetails_nonmoving_gc_sync_cpu_ns") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 RtsTime) :*: S1 ('MetaSel ('Just "gcdetails_nonmoving_gc_sync_elapsed_ns") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 RtsTime)))))))Defined in ghc-internal-9.1003.0 · GHC.Internal.Stats

typetype RtsTime = Int64

Time values from the RTS, using a fixed resolution of nanoseconds.

valuegetRTSStats :: IO RTSStats

Get current runtime system statistics.

valuegetRTSStatsEnabled :: IO Bool

Returns whether GC stats have been enabled (with +RTS -T, for example).