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authorMatthew Pickering <matthewtpickering@gmail.com>2020-12-07 13:19:28 +0000
committerMarge Bot <ben+marge-bot@smart-cactus.org>2021-03-03 08:12:29 -0500
commitd89deeba47ce04a5198a71fa4cbc203fe2c90794 (patch)
tree8f879bbb0774ce686e1688cc638ef22179babf51 /libraries/base/GHC
parentd8dc0f96237fe6fe7081c04727c7c2573477e5cb (diff)
downloadhaskell-d89deeba47ce04a5198a71fa4cbc203fe2c90794.tar.gz
Profiling: Allow heap profiling to be controlled dynamically.
This patch exposes three new functions in `GHC.Profiling` which allow heap profiling to be enabled and disabled dynamically. 1. startHeapProfTimer - Starts heap profiling with the given RTS options 2. stopHeapProfTimer - Stops heap profiling 3. requestHeapCensus - Perform a heap census on the next context switch, regardless of whether the timer is enabled or not.
Diffstat (limited to 'libraries/base/GHC')
-rw-r--r--libraries/base/GHC/Profiling.hs32
-rw-r--r--libraries/base/GHC/RTS/Flags.hsc3
2 files changed, 34 insertions, 1 deletions
diff --git a/libraries/base/GHC/Profiling.hs b/libraries/base/GHC/Profiling.hs
index 917a208b30..b7cef2fecd 100644
--- a/libraries/base/GHC/Profiling.hs
+++ b/libraries/base/GHC/Profiling.hs
@@ -2,7 +2,14 @@
{-# LANGUAGE NoImplicitPrelude #-}
-- | @since 4.7.0.0
-module GHC.Profiling where
+module GHC.Profiling ( -- * Cost Centre Profiling
+ startProfTimer
+ , stopProfTimer
+ -- * Heap Profiling
+ , startHeapProfTimer
+ , stopHeapProfTimer
+ , requestHeapCensus
+ )where
import GHC.Base
@@ -17,3 +24,26 @@ foreign import ccall stopProfTimer :: IO ()
--
-- @since 4.7.0.0
foreign import ccall startProfTimer :: IO ()
+
+-- | Request a heap census on the next context switch. The census can be
+-- requested whether or not the heap profiling timer is running.
+-- Note: This won't do anything unless you also specify a profiling mode on the
+-- command line using the normal RTS options.
+--
+-- @since 4.16.0.0
+foreign import ccall requestHeapCensus :: IO ()
+
+-- | Start heap profiling. This is called normally by the RTS on start-up,
+-- but can be disabled using the rts flag `--no-automatic-heap-samples`
+-- Note: This won't do anything unless you also specify a profiling mode on the
+-- command line using the normal RTS options.
+--
+-- @since 4.16.0.0
+foreign import ccall startHeapProfTimer :: IO ()
+
+-- | Stop heap profiling.
+-- Note: This won't do anything unless you also specify a profiling mode on the
+-- command line using the normal RTS options.
+--
+-- @since 4.16.0.0
+foreign import ccall stopHeapProfTimer :: IO ()
diff --git a/libraries/base/GHC/RTS/Flags.hsc b/libraries/base/GHC/RTS/Flags.hsc
index 2130ee1aaa..2f161c72c3 100644
--- a/libraries/base/GHC/RTS/Flags.hsc
+++ b/libraries/base/GHC/RTS/Flags.hsc
@@ -288,6 +288,7 @@ data ProfFlags = ProfFlags
{ doHeapProfile :: DoHeapProfile
, heapProfileInterval :: RtsTime -- ^ time between samples
, heapProfileIntervalTicks :: Word -- ^ ticks between samples (derived)
+ , startHeapProfileAtStartup :: Bool
, showCCSOnException :: Bool
, maxRetainerSetSize :: Word
, ccsLength :: Word
@@ -584,6 +585,8 @@ getProfFlags = do
<*> #{peek PROFILING_FLAGS, heapProfileInterval} ptr
<*> #{peek PROFILING_FLAGS, heapProfileIntervalTicks} ptr
<*> (toBool <$>
+ (#{peek PROFILING_FLAGS, startHeapProfileAtStartup} ptr :: IO CBool))
+ <*> (toBool <$>
(#{peek PROFILING_FLAGS, showCCSOnException} ptr :: IO CBool))
<*> #{peek PROFILING_FLAGS, maxRetainerSetSize} ptr
<*> #{peek PROFILING_FLAGS, ccsLength} ptr