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llvm-mirror/docs/CommandGuide/llvm-profdata.rst
Vedant Kumar 6f6a5a74b9 [llvm-profdata] Add mode to recover from profile read failures
Add a mode in which profile read errors are not immediately treated as
fatal. In this mode, merging makes forward progress and reports failure
only if no inputs can be read.

Differential Revision: https://reviews.llvm.org/D66985

llvm-svn: 370827
2019-09-03 22:23:16 +00:00

315 lines
8.9 KiB
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llvm-profdata - Profile data tool
=================================
.. program:: llvm-profdata
SYNOPSIS
--------
:program:`llvm-profdata` *command* [*args...*]
DESCRIPTION
-----------
The :program:`llvm-profdata` tool is a small utility for working with profile
data files.
COMMANDS
--------
* :ref:`merge <profdata-merge>`
* :ref:`show <profdata-show>`
* :ref:`overlap <profdata-overlap>`
.. program:: llvm-profdata merge
.. _profdata-merge:
MERGE
-----
SYNOPSIS
^^^^^^^^
:program:`llvm-profdata merge` [*options*] [*filename...*]
DESCRIPTION
^^^^^^^^^^^
:program:`llvm-profdata merge` takes several profile data files
generated by PGO instrumentation and merges them together into a single
indexed profile data file.
By default profile data is merged without modification. This means that the
relative importance of each input file is proportional to the number of samples
or counts it contains. In general, the input from a longer training run will be
interpreted as relatively more important than a shorter run. Depending on the
nature of the training runs it may be useful to adjust the weight given to each
input file by using the ``-weighted-input`` option.
Profiles passed in via ``-weighted-input``, ``-input-files``, or via positional
arguments are processed once for each time they are seen.
OPTIONS
^^^^^^^
.. option:: -help
Print a summary of command line options.
.. option:: -output=output, -o=output
Specify the output file name. *Output* cannot be ``-`` as the resulting
indexed profile data can't be written to standard output.
.. option:: -weighted-input=weight,filename
Specify an input file name along with a weight. The profile counts of the
supplied ``filename`` will be scaled (multiplied) by the supplied
``weight``, where where ``weight`` is a decimal integer >= 1.
Input files specified without using this option are assigned a default
weight of 1. Examples are shown below.
.. option:: -input-files=path, -f=path
Specify a file which contains a list of files to merge. The entries in this
file are newline-separated. Lines starting with '#' are skipped. Entries may
be of the form <filename> or <weight>,<filename>.
.. option:: -remapping-file=path, -r=path
Specify a file which contains a remapping from symbol names in the input
profile to the symbol names that should be used in the output profile. The
file should consist of lines of the form ``<input-symbol> <output-symbol>``.
Blank lines and lines starting with ``#`` are skipped.
The :doc:`llvm-cxxmap <llvm-cxxmap>` tool can be used to generate the symbol
remapping file.
.. option:: -instr (default)
Specify that the input profile is an instrumentation-based profile.
.. option:: -sample
Specify that the input profile is a sample-based profile.
The format of the generated file can be generated in one of three ways:
.. option:: -binary (default)
Emit the profile using a binary encoding. For instrumentation-based profile
the output format is the indexed binary format.
.. option:: -text
Emit the profile in text mode. This option can also be used with both
sample-based and instrumentation-based profile. When this option is used
the profile will be dumped in the text format that is parsable by the profile
reader.
.. option:: -gcc
Emit the profile using GCC's gcov format (Not yet supported).
.. option:: -sparse[=true|false]
Do not emit function records with 0 execution count. Can only be used in
conjunction with -instr. Defaults to false, since it can inhibit compiler
optimization during PGO.
.. option:: -num-threads=N, -j=N
Use N threads to perform profile merging. When N=0, llvm-profdata auto-detects
an appropriate number of threads to use. This is the default.
.. option:: -failure-mode=[any|all]
Set the failure mode. There are two options: 'any' causes the merge command to
fail if any profiles are invalid, and 'all' causes the merge command to fail
only if all profiles are invalid. If 'all' is set, information from any
invalid profiles is excluded from the final merged product. The default
failure mode is 'any'.
EXAMPLES
^^^^^^^^
Basic Usage
+++++++++++
Merge three profiles:
::
llvm-profdata merge foo.profdata bar.profdata baz.profdata -output merged.profdata
Weighted Input
++++++++++++++
The input file `foo.profdata` is especially important, multiply its counts by 10:
::
llvm-profdata merge -weighted-input=10,foo.profdata bar.profdata baz.profdata -output merged.profdata
Exactly equivalent to the previous invocation (explicit form; useful for programmatic invocation):
::
llvm-profdata merge -weighted-input=10,foo.profdata -weighted-input=1,bar.profdata -weighted-input=1,baz.profdata -output merged.profdata
.. program:: llvm-profdata show
.. _profdata-show:
SHOW
----
SYNOPSIS
^^^^^^^^
:program:`llvm-profdata show` [*options*] [*filename*]
DESCRIPTION
^^^^^^^^^^^
:program:`llvm-profdata show` takes a profile data file and displays the
information about the profile counters for this file and
for any of the specified function(s).
If *filename* is omitted or is ``-``, then **llvm-profdata show** reads its
input from standard input.
OPTIONS
^^^^^^^
.. option:: -all-functions
Print details for every function.
.. option:: -counts
Print the counter values for the displayed functions.
.. option:: -function=string
Print details for a function if the function's name contains the given string.
.. option:: -help
Print a summary of command line options.
.. option:: -output=output, -o=output
Specify the output file name. If *output* is ``-`` or it isn't specified,
then the output is sent to standard output.
.. option:: -instr (default)
Specify that the input profile is an instrumentation-based profile.
.. option:: -text
Instruct the profile dumper to show profile counts in the text format of the
instrumentation-based profile data representation. By default, the profile
information is dumped in a more human readable form (also in text) with
annotations.
.. option:: -topn=n
Instruct the profile dumper to show the top ``n`` functions with the
hottest basic blocks in the summary section. By default, the topn functions
are not dumped.
.. option:: -sample
Specify that the input profile is a sample-based profile.
.. option:: -memop-sizes
Show the profiled sizes of the memory intrinsic calls for shown functions.
.. option:: -value-cutoff=n
Show only those functions whose max count values are greater or equal to ``n``.
By default, the value-cutoff is set to 0.
.. option:: -list-below-cutoff
Only output names of functions whose max count value are below the cutoff
value.
.. option:: -showcs
Only show context sensitive profile counts. The default is to filter all
context sensitive profile counts.
.. program:: llvm-profdata overlap
.. _profdata-overlap:
OVERLAP
-------
SYNOPSIS
^^^^^^^^
:program:`llvm-profdata overlap` [*options*] [*base profile file*] [*test profile file*]
DESCRIPTION
^^^^^^^^^^^
:program:`llvm-profdata overlap` takes two profile data files and displays the
*overlap* of counter distribution between the whole files and between any of the
specified functions.
In this command, *overlap* is defined as follows:
Suppose *base profile file* has the following counts:
{c1_1, c1_2, ..., c1_n, c1_u_1, c2_u_2, ..., c2_u_s},
and *test profile file* has
{c2_1, c2_2, ..., c2_n, c2_v_1, c2_v_2, ..., c2_v_t}.
Here c{1|2}_i (i = 1 .. n) are matched counters and c1_u_i (i = 1 .. s) and
c2_v_i (i = 1 .. v) are unmatched counters (or counters only existing in)
*base profile file* and *test profile file*, respectively.
Let sum_1 = c1_1 + c1_2 + ... + c1_n + c1_u_1 + c2_u_2 + ... + c2_u_s, and
sum_2 = c2_1 + c2_2 + ... + c2_n + c2_v_1 + c2_v_2 + ... + c2_v_t.
*overlap* = min(c1_1/sum_1, c2_1/sum_2) + min(c1_2/sum_1, c2_2/sum_2) + ...
+ min(c1_n/sum_1, c2_n/sum_2).
The result overlap distribution is a percentage number, ranging from 0.0% to
100.0%, where 0.0% means there is no overlap and 100.0% means a perfect
overlap.
Here is an example, if *base profile file* has counts of {400, 600}, and
*test profile file* has matched counts of {60000, 40000}. The *overlap* is 80%.
OPTIONS
^^^^^^^
.. option:: -function=string
Print details for a function if the function's name contains the given string.
.. option:: -help
Print a summary of command line options.
.. option:: -o=output or -o output
Specify the output file name. If *output* is ``-`` or it isn't specified,
then the output is sent to standard output.
.. option:: -value-cutoff=n
Show only those functions whose max count values are greater or equal to ``n``.
By default, the value-cutoff is set to max of unsigned long long.
.. option:: -cs
Only show overlap for the context sensitive profile counts. The default is to show
non-context sensitive profile counts.
EXIT STATUS
-----------
:program:`llvm-profdata` returns 1 if the command is omitted or is invalid,
if it cannot read input files, or if there is a mismatch between their data.