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GHC.Stats

Safe Haskell	Trustworthy
Language	Haskell2010

Runtime statistics
DEPRECATED, don't use

Description

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.

This module is GHC-only and should not be considered portable.

Since: 4.5.0.0

Runtime statistics

data RTSStats Source

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

Since: 4.9.0.0

Constructors

RTSStats

Fields

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)
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
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)
gc :: GCDetails
Details about the most recent GC

Instances

Read RTSStats
Methods readsPrec :: Int -> ReadS RTSStats Source readList :: ReadS [RTSStats] Source readPrec :: ReadPrec RTSStats Source readListPrec :: ReadPrec [RTSStats] Source
Show RTSStats
Methods showsPrec :: Int -> RTSStats -> ShowS Source show :: RTSStats -> String Source showList :: [RTSStats] -> ShowS Source

data GCDetails Source

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

Fields

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 (incliudes large + compact data)
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
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

Instances

Read GCDetails
Methods readsPrec :: Int -> ReadS GCDetails Source readList :: ReadS [GCDetails] Source readPrec :: ReadPrec GCDetails Source readListPrec :: ReadPrec [GCDetails] Source
Show GCDetails
Methods showsPrec :: Int -> GCDetails -> ShowS Source show :: GCDetails -> String Source showList :: [GCDetails] -> ShowS Source

type RtsTime = Int64 Source

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

getRTSStats :: IO RTSStats Source

getRTSStatsEnabled :: IO Bool Source

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

Since: 4.9.0.0

DEPRECATED, don't use

data GCStats Source

Deprecated: Use RTSStats instead. This will be removed in GHC 8.4.1

Statistics about memory usage and the garbage collector. Apart from currentBytesUsed and currentBytesSlop all are cumulative values since the program started.

Since: 4.5.0.0

Constructors

GCStats

Deprecated: Use RTSStats instead. This will be removed in GHC 8.4.1

Fields

bytesAllocated :: !Int64
Total number of bytes allocated
numGcs :: !Int64
Number of garbage collections performed (any generation, major and minor)
maxBytesUsed :: !Int64
Maximum number of live bytes seen so far
numByteUsageSamples :: !Int64
Number of byte usage samples taken, or equivalently the number of major GCs performed.
cumulativeBytesUsed :: !Int64
Sum of all byte usage samples, can be used with numByteUsageSamples to calculate averages with arbitrary weighting (if you are sampling this record multiple times).
bytesCopied :: !Int64
Number of bytes copied during GC
currentBytesUsed :: !Int64
Number of live bytes at the end of the last major GC
currentBytesSlop :: !Int64
Current number of bytes lost to slop
maxBytesSlop :: !Int64
Maximum number of bytes lost to slop at any one time so far
peakMegabytesAllocated :: !Int64
Maximum number of megabytes allocated
mblocksAllocated :: !Int64
Number of allocated megablocks
mutatorCpuSeconds :: !Double
mutatorWallSeconds :: !Double
Wall clock time spent running mutator threads. This does not include initialization.
gcCpuSeconds :: !Double
CPU time spent running GC
gcWallSeconds :: !Double
Wall clock time spent running GC
cpuSeconds :: !Double
Total CPU time elapsed since program start
wallSeconds :: !Double
Total wall clock time elapsed since start
parTotBytesCopied :: !Int64
Number of bytes copied during GC, minus space held by mutable lists held by the capabilities. Can be used with parMaxBytesCopied to determine how well parallel GC utilized all cores.
parMaxBytesCopied :: !Int64
Sum of number of bytes copied each GC by the most active GC thread each GC. The ratio of parTotBytesCopied divided by parMaxBytesCopied approaches 1 for a maximally sequential run and approaches the number of threads (set by the RTS flag -N) for a maximally parallel run.

Instances

Read GCStats
Methods readsPrec :: Int -> ReadS GCStats Source readList :: ReadS [GCStats] Source readPrec :: ReadPrec GCStats Source readListPrec :: ReadPrec [GCStats] Source
Show GCStats
Methods showsPrec :: Int -> GCStats -> ShowS Source show :: GCStats -> String Source showList :: [GCStats] -> ShowS Source

getGCStats :: IO GCStats Source

Deprecated: Use getRTSStats instead. This will be removed in GHC 8.4.1

Retrieves garbage collection and memory statistics as of the last garbage collection. If you would like your statistics as recent as possible, first run a performGC.

Since: 4.5.0.0

getGCStatsEnabled :: IO Bool Source

Deprecated: use getRTSStatsEnabled instead. This will be removed in GHC 8.4.1

© The University of Glasgow and others
Licensed under a BSD-style license (see top of the page).
https://downloads.haskell.org/~ghc/8.2.1/docs/html/libraries/base-4.10.0.0/GHC-Stats.html

GHC.Stats

Contents

Description

Runtime statistics

Constructors

Fields

Instances

Methods

Methods

Constructors

Fields

Instances

Methods

Methods

DEPRECATED, don't use

Constructors

Fields

Instances

Methods

Methods