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authorBen Gamari <ben@smart-cactus.org>2020-11-11 15:51:50 -0500
committerSebastian Graf <sebastian.graf@kit.edu>2020-11-19 21:29:32 +0100
commitb112b04206bf0c086548759665776c847d58ad4d (patch)
treefe36385e1f8670d06b0ebfd3c6b2f5f693810a11
parent8150f6546e6fd0006252e245d5697f13ffd8ce3e (diff)
downloadhaskell-b112b04206bf0c086548759665776c847d58ad4d.tar.gz
users-guide: A bit of clean-up in profiling flag documentation
-rw-r--r--docs/users_guide/profiling.rst74
1 files changed, 31 insertions, 43 deletions
diff --git a/docs/users_guide/profiling.rst b/docs/users_guide/profiling.rst
index e7b1b7e455..77e00bbbe4 100644
--- a/docs/users_guide/profiling.rst
+++ b/docs/users_guide/profiling.rst
@@ -332,19 +332,41 @@ Compiler options for profiling
Without a :ghc-flag:`-prof` option, your ``SCC``\ s are ignored; so you can
compile ``SCC``-laden code without changing it.
+.. ghc-flag:: -fno-prof-count-entries
+ :shortdesc: Do not collect entry counts
+ :type: dynamic
+ :reverse: -fprof-count-entries
+ :category:
+
+ Tells GHC not to collect information about how often functions are
+ entered at runtime (the "entries" column of the time profile), for
+ this module. This tends to make the profiled code run faster, and
+ hence closer to the speed of the unprofiled code, because GHC is
+ able to optimise more aggressively if it doesn't have to maintain
+ correct entry counts. This option can be useful if you aren't
+ interested in the entry counts (for example, if you only intend to
+ do heap profiling).
+
+
There are a few other profiling-related compilation options. Use them
*in addition to* :ghc-flag:`-prof`. These do not have to be used consistently
for all modules in a program.
+Automatically placing cost-centres
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+GHC has a number of flags for automatically inserting cost-centres into the
+compiled program.
+
.. ghc-flag:: -fprof-auto
:shortdesc: Auto-add ``SCC``\\ s to all bindings not marked INLINE
:type: dynamic
:reverse: -fno-prof-auto
:category:
- *All* bindings not marked INLINE, whether exported or not, top level
- or nested, will be given automatic ``SCC`` annotations. Functions
- marked INLINE must be given a cost centre manually.
+ *All* bindings not marked :pragma:`INLINE`, whether exported or not, top
+ level or nested, will be given automatic ``SCC`` annotations. Functions
+ marked :pragma:`INLINE` must be given a cost centre manually.
.. ghc-flag:: -fprof-auto-top
:shortdesc: Auto-add ``SCC``\\ s to all top-level bindings not marked INLINE
@@ -356,11 +378,11 @@ for all modules in a program.
single: cost centres; automatically inserting
GHC will automatically add ``SCC`` annotations for all top-level
- bindings not marked INLINE. If you want a cost centre on an INLINE
- function, you have to add it manually.
+ bindings not marked :pragma:`INLINE`. If you want a cost centre on an
+ :pragma:`INLINE` function, you have to add it manually.
.. ghc-flag:: -fprof-auto-exported
- :shortdesc: Auto-add ``SCC``\\ s to all exported bindings not marked INLINE
+ :shortdesc: Auto-add ``SCC``\\ s to all exported bindings not marked :pragma:`INLINE`
:type: dynamic
:reverse: -fno-prof-auto
:category:
@@ -369,8 +391,8 @@ for all modules in a program.
single: cost centres; automatically inserting
GHC will automatically add ``SCC`` annotations for all exported
- functions not marked INLINE. If you want a cost centre on an INLINE
- function, you have to add it manually.
+ functions not marked :pragma:`INLINE`. If you want a cost centre on an
+ :pragma:`INLINE` function, you have to add it manually.
.. ghc-flag:: -fprof-auto-calls
:shortdesc: Auto-add ``SCC``\\ s to all call sites
@@ -392,41 +414,7 @@ for all modules in a program.
The costs of all CAFs in a module are usually attributed to one
"big" CAF cost-centre. With this option, all CAFs get their own
- cost-centre. An “if all else fails” option…
-
-.. ghc-flag:: -fno-prof-auto
- :shortdesc: Disables any previous :ghc-flag:`-fprof-auto`,
- :ghc-flag:`-fprof-auto-top`, or :ghc-flag:`-fprof-auto-exported` options.
- :type: dynamic
- :reverse: -fprof-auto
- :category:
-
- Disables any previous :ghc-flag:`-fprof-auto`, :ghc-flag:`-fprof-auto-top`, or
- :ghc-flag:`-fprof-auto-exported` options.
-
-.. ghc-flag:: -fno-prof-cafs
- :shortdesc: Disables any previous :ghc-flag:`-fprof-cafs` option.
- :type: dynamic
- :reverse: -fprof-cafs
- :category:
-
- Disables any previous :ghc-flag:`-fprof-cafs` option.
-
-.. ghc-flag:: -fno-prof-count-entries
- :shortdesc: Do not collect entry counts
- :type: dynamic
- :reverse: -fprof-count-entries
- :category:
-
- Tells GHC not to collect information about how often functions are
- entered at runtime (the "entries" column of the time profile), for
- this module. This tends to make the profiled code run faster, and
- hence closer to the speed of the unprofiled code, because GHC is
- able to optimise more aggressively if it doesn't have to maintain
- correct entry counts. This option can be useful if you aren't
- interested in the entry counts (for example, if you only intend to
- do heap profiling).
-
+ cost-centre. An "if all else fails" option…
.. ghc-flag:: -auto-all
:shortdesc: *(deprecated)* Alias for :ghc-flag:`-fprof-auto`