Re: [PATCH v2] Implement benchmark script in python

[Siddhesh Poyarekar <siddhesh at redhat dot com>]

On Tue, Dec 31, 2013 at 03:45:30AM -0500, Mike Frysinger wrote:
> largely looks good.  mostly nits below.
> 
> when it comes to declaring coding style, i'm not sure the GNU project has one 
> already for python (since they try to push Guile/scheme).  GDB has been 
> growing a python code base, but a scan of that tree doesn't turn up anything 
> either :(.
> 
> looking around the glibc tree, i think adding a section to manual/maint.texi 
> would be the best bet.

Wouldn't [1] be a good place for this kind of documentation?

[1] https://sourceware.org/glibc/wiki/Style_and_Conventions

However, I believe we should have an in-tree document that at least
points to the relevant wiki pages for occasional contributors.

> > --- /dev/null
> > +++ b/scripts/pylintrc
> 
> any reason for that vs generating a default one and tweaking it ?  see 
> pylint's --generate-rcfile option.

In fact, I generated the default and dumped everything I didn't
change, thinking that it would be easier for you to review a smaller
file :) I've included the generated and tweaked rcfile now.  How does
this iteration look?

Siddhesh


	* scripts/bench.pl: Remove file.
	* scripts/bench.py: New benchmark script.
	* benchtests/Makefile ($(objpfx)bench-%.c): Use it.
	* benchtests/README: Mention python dependency.
	* scripts/pylintrc: New file.
	* scripts/pylint: New file.

diff --git a/benchtests/Makefile b/benchtests/Makefile
index 117228b..3d41274 100644
--- a/benchtests/Makefile
+++ b/benchtests/Makefile
@@ -127,5 +127,5 @@ $(objpfx)bench-%.c: %-inputs $(bench-deps)
 	{ if [ -n "$($*-INCLUDE)" ]; then \
 	  cat $($*-INCLUDE); \
 	fi; \
-	$(..)scripts/bench.pl $(patsubst %-inputs,%,$<); } > $@-tmp
+	$(..)scripts/bench.py $(patsubst %-inputs,%,$<); } > $@-tmp
 	mv -f $@-tmp $@
diff --git a/benchtests/README b/benchtests/README
index a5fd8da..2a940fa 100644
--- a/benchtests/README
+++ b/benchtests/README
@@ -8,7 +8,9 @@ basic performance properties of the function.
 Running the benchmark:
 =====================
 
-The benchmark can be executed by invoking make as follows:
+The benchmark needs python 2.7 or later in addition to the
+dependencies required to build the GNU C Library.  One may run the
+benchmark by invoking make as follows:
 
   $ make bench
 
diff --git a/scripts/bench.pl b/scripts/bench.pl
deleted file mode 100755
index 10f0ba4..0000000
diff --git a/scripts/bench.py b/scripts/bench.py
new file mode 100755
index 0000000..7c3ef04
--- /dev/null
+++ b/scripts/bench.py
@@ -0,0 +1,299 @@
+#!/usr/bin/python
+# Copyright (C) 2013 Free Software Foundation, Inc.
+# This file is part of the GNU C Library.
+#
+# The GNU C Library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# The GNU C Library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with the GNU C Library; if not, see
+# <http://www.gnu.org/licenses/>.
+
+"""Benchmark program generator script
+
+This script takes a function name as input and generates a program using
+an input file located in the benchtests directory.  The name of the
+input file should be of the form foo-inputs where 'foo' is the name of
+the function.
+"""
+
+from __future__ import print_function
+import sys
+import os
+import itertools
+
+# Macro definitions for functions that take no arguments.  For functions
+# that take arguments, the STRUCT_TEMPLATE, ARGS_TEMPLATE and
+# VARIANTS_TEMPLATE are used instead.
+DEFINES_TEMPLATE = '''
+#define CALL_BENCH_FUNC(v, i) %(func)s ()
+#define NUM_VARIANTS (1)
+#define NUM_SAMPLES(v) (1)
+#define VARIANT(v) FUNCNAME "()"
+'''
+
+# Structures to store arguments for the function call.  A function may
+# have its inputs partitioned to represent distinct performance
+# characteristics or distinct flavors of the function.  Each such
+# variant is represented by the _VARIANT structure.  The ARGS structure
+# represents a single set of arguments.
+STRUCT_TEMPLATE = '''
+#define CALL_BENCH_FUNC(v, i) %(func)s (%(func_args)s)
+
+struct args
+{
+%(args)s
+};
+
+struct _variants
+{
+  const char *name;
+  int count;
+  struct args *in;
+};
+'''
+
+# The actual input arguments.
+ARGS_TEMPLATE = '''
+struct args in%(argnum)d[%(num_args)d] = {
+%(args)s
+};
+'''
+
+# The actual variants, along with macros defined to access the variants.
+VARIANTS_TEMPLATE = '''
+struct _variants variants[%(num_variants)d] = {
+%(variants)s
+};
+
+#define NUM_VARIANTS %(num_variants)d
+#define NUM_SAMPLES(i) (variants[i].count)
+#define VARIANT(i) (variants[i].name)
+'''
+
+# Epilogue for the generated source file.
+EPILOGUE = '''
+#define BENCH_FUNC(i, j) ({%(getret)s CALL_BENCH_FUNC (i, j);})
+#define FUNCNAME "%(func)s"
+#include "bench-skeleton.c"'''
+
+
+def gen_source(func, directives, all_vals):
+    """Generate source for the function
+
+    Generate the C source for the function from the values and
+    directives.
+
+    Args:
+      func: The function name
+      directives: A dictionary of directives applicable to this function
+      all_vals: A dictionary input values
+    """
+    # The includes go in first.
+    for header in directives['includes']:
+        print('#include <%s>' % header)
+
+    for header in directives['include-sources']:
+        print('#include "%s"' % header)
+
+    # Print macros.  This branches out to a separate routine if
+    # the function takes arguments.
+    if not directives['args']:
+        print(DEFINES_TEMPLATE % {'func': func})
+        outargs = []
+    else:
+        outargs = _print_arg_data(func, directives, all_vals)
+
+    # Print the output variable definitions if necessary.
+    for out in outargs:
+        print(out)
+
+    # If we have a return value from the function, make sure it is
+    # assigned to prevent the compiler from optimizing out the
+    # call.
+    if directives['ret']:
+        print('static %s volatile ret;' % directives['ret'])
+        getret = 'ret = '
+    else:
+        getret = ''
+
+    print(EPILOGUE % {'getret': getret, 'func': func})
+
+
+def _print_arg_data(func, directives, all_vals):
+    """Print argument data
+
+    This is a helper function for gen_source that prints structure and
+    values for arguments and their variants and returns output arguments
+    if any are found.
+
+    Args:
+      func: Function name
+      directives: A dictionary of directives applicable to this function
+      all_vals: A dictionary input values
+
+    Returns:
+      Returns a list of definitions for function arguments that act as
+      output parameters.
+    """
+    # First, all of the definitions.  We process writing of
+    # CALL_BENCH_FUNC, struct args and also the output arguments
+    # together in a single traversal of the arguments list.
+    func_args = []
+    arg_struct = []
+    outargs = []
+
+    for arg, i in zip(directives['args'], itertools.count()):
+        if arg[0] == '<' and arg[-1] == '>':
+            pos = arg.rfind('*')
+            if pos == -1:
+                die('Output argument must be a pointer type')
+
+            outargs.append('static %s out%d;' % (arg[1:pos], i))
+            func_args.append(' &out%d' % i)
+        else:
+            arg_struct.append('  %s volatile arg%d;' % (arg, i))
+            func_args.append('variants[v].in[i].arg%d' % i)
+
+    print(STRUCT_TEMPLATE % {'args' : '\n'.join(arg_struct), 'func': func,
+                             'func_args': ', '.join(func_args)})
+
+    # Now print the values.
+    variants = []
+    for (k, vals), i in zip(all_vals.items(), itertools.count()):
+        out = ['  {%s},' % v for v in vals]
+
+        # Members for the variants structure list that we will
+        # print later.
+        variants.append('  {"%s(%s)", %d, in%d},' % (func, k, len(vals), i))
+        print(ARGS_TEMPLATE % {'argnum': i, 'num_args': len(vals),
+                               'args': '\n'.join(out)})
+
+    # Print the variants and the last set of macros.
+    print(VARIANTS_TEMPLATE % {'num_variants': len(all_vals),
+                               'variants': '\n'.join(variants)})
+    return outargs
+
+
+def _process_directive(d_name, d_val):
+    """Process a directive.
+
+    Evaluate the directive name and value passed and return the
+    processed value. This is a helper function for parse_file.
+
+    Args:
+      d_name: Name of the directive
+      d_value: The string value to process
+
+    Returns:
+      The processed value, which may be the string as it is or an object
+      that describes the directive.
+    """
+    # Process the directive values if necessary.  name and ret don't
+    # need any processing.
+    if d_name.startswith('include'):
+        d_val = d_val.split(',')
+    elif d_name == 'args':
+        d_val = d_val.split(':')
+
+    # Return the values.
+    return d_val
+
+
+def parse_file(func):
+    """Parse an input file
+
+    Given a function name, open and parse an input file for the function
+    and get the necessary parameters for the generated code and the list
+    of inputs.
+
+    Args:
+      func: The function name
+
+    Returns:
+      A tuple of two elements, one a dictionary of directives and the
+      other a dictionary of all input values.
+    """
+    all_vals = {}
+    # Valid directives.
+    directives = {
+            'name': '',
+            'args': [],
+            'includes': [],
+            'include-sources': [],
+            'ret': ''
+    }
+
+    try:
+        with open('%s-inputs' % func) as f:
+            for line in f:
+                # Look for directives and parse it if found.
+                if line.startswith('##'):
+                    try:
+                        d_name, d_val = line[2:].split(':', 1)
+                        d_name = d_name.strip()
+                        d_val = d_val.strip()
+                        directives[d_name] = _process_directive(d_name, d_val)
+                    except (IndexError, KeyError):
+                        die('Invalid directive: %s' % line[2:])
+
+                # Skip blank lines and comments.
+                line = line.split('#', 1)[0].rstrip()
+                if not line:
+                    continue
+
+                # Otherwise, we're an input.  Add to the appropriate
+                # input set.
+                cur_name = directives['name']
+                all_vals.setdefault(cur_name, [])
+                all_vals[cur_name].append(line)
+    except IOError as ex:
+        die("Failed to open input file (%s): %s" % (ex.filename, ex.strerror))
+
+    return directives, all_vals
+
+
+def die(msg):
+    """Exit with an error
+
+    Prints an error message to the standard error stream and exits with
+    a non-zero status.
+
+    Args:
+      msg: The error message to print to standard error.
+    """
+    print('%s\n' % msg, file=sys.stderr)
+    sys.exit(os.EX_DATAERR)
+
+
+def main(args):
+    """Main function
+
+    Use the first command line argument as function name and parse its
+    input file to generate C source that calls the function repeatedly
+    for the input.
+
+    Args:
+      args: The command line arguments with the program name dropped.
+
+    Returns:
+      os.EX_USAGE on error and os.EX_OK on success.
+    """
+    if len(args) != 1:
+        print('Usage: %s <function>' % sys.argv[0])
+        return os.EX_USAGE
+
+    directives, all_vals = parse_file(args[0])
+    gen_source(args[0], directives, all_vals)
+    return os.EX_OK
+
+
+if __name__ == '__main__':
+    sys.exit(main(sys.argv[1:]))
diff --git a/scripts/pylint b/scripts/pylint
new file mode 100755
index 0000000..49a775e
--- /dev/null
+++ b/scripts/pylint
@@ -0,0 +1,5 @@
+#!/bin/sh
+# Simple wrapper around the pylint program that uses the pylintrc file to
+# validate the source code in files passed on command line.
+
+exec pylint --rcfile "${0%/*}/pylintrc" "$@"
diff --git a/scripts/pylintrc b/scripts/pylintrc
new file mode 100644
index 0000000..a05ddfd
--- /dev/null
+++ b/scripts/pylintrc
@@ -0,0 +1,274 @@
+[MASTER]
+
+# Specify a configuration file.
+#rcfile=
+
+# Python code to execute, usually for sys.path manipulation such as
+# pygtk.require().
+#init-hook=
+
+# Profiled execution.
+profile=no
+
+# Add files or directories to the blacklist. They should be base names, not
+# paths.
+ignore=CVS
+
+# Pickle collected data for later comparisons.
+persistent=yes
+
+# List of plugins (as comma separated values of python modules names) to load,
+# usually to register additional checkers.
+load-plugins=
+
+
+[MESSAGES CONTROL]
+
+# Enable the message, report, category or checker with the given id(s). You can
+# either give multiple identifier separated by comma (,) or put this option
+# multiple time. See also the "--disable" option for examples.
+#enable=
+
+# Disable the message, report, category or checker with the given id(s). You
+# can either give multiple identifiers separated by comma (,) or put this
+# option multiple times (only on the command line, not in the configuration
+# file where it should appear only once).You can also use "--disable=all" to
+# disable everything first and then reenable specific checks. For example, if
+# you want to run only the similarities checker, you can use "--disable=all
+# --enable=similarities". If you want to run only the classes checker, but have
+# no Warning level messages displayed, use"--disable=all --enable=classes
+# --disable=W"
+#disable=
+
+
+[REPORTS]
+
+# Set the output format. Available formats are text, parseable, colorized, msvs
+# (visual studio) and html. You can also give a reporter class, eg
+# mypackage.mymodule.MyReporterClass.
+output-format=text
+
+# Put messages in a separate file for each module / package specified on the
+# command line instead of printing them on stdout. Reports (if any) will be
+# written in a file name "pylint_global.[txt|html]".
+files-output=no
+
+# Tells whether to display a full report or only the messages
+reports=yes
+
+# Python expression which should return a note less than 10 (10 is the highest
+# note). You have access to the variables errors warning, statement which
+# respectively contain the number of errors / warnings messages and the total
+# number of statements analyzed. This is used by the global evaluation report
+# (RP0004).
+evaluation=10.0 - ((float(5 * error + warning + refactor + convention) / statement) * 10)
+
+# Add a comment according to your evaluation note. This is used by the global
+# evaluation report (RP0004).
+comment=no
+
+# Template used to display messages. This is a python new-style format string
+# used to format the massage information. See doc for all details
+#msg-template=
+
+
+[MISCELLANEOUS]
+
+# List of note tags to take in consideration, separated by a comma.
+notes=FIXME,XXX,TODO
+
+
+[SIMILARITIES]
+
+# Minimum lines number of a similarity.
+min-similarity-lines=4
+
+# Ignore comments when computing similarities.
+ignore-comments=yes
+
+# Ignore docstrings when computing similarities.
+ignore-docstrings=yes
+
+# Ignore imports when computing similarities.
+ignore-imports=no
+
+
+[BASIC]
+
+# Required attributes for module, separated by a comma
+required-attributes=
+
+# List of builtins function names that should not be used, separated by a comma
+bad-functions=map,filter,apply,input
+
+# Regular expression which should only match correct module names
+module-rgx=(([a-z_][a-z0-9_]*)|([A-Z][a-zA-Z0-9]+))$
+
+# Regular expression which should only match correct module level names
+const-rgx=(([A-Z_][A-Z0-9_]*)|(__.*__))$
+
+# Regular expression which should only match correct class names
+class-rgx=[A-Z_][a-zA-Z0-9]+$
+
+# Regular expression which should only match correct function names
+function-rgx=[a-z_][a-z0-9_]{2,30}$
+
+# Regular expression which should only match correct method names
+method-rgx=[a-z_][a-z0-9_]{2,30}$
+
+# Regular expression which should only match correct instance attribute names
+attr-rgx=[a-z_][a-z0-9_]{2,30}$
+
+# Regular expression which should only match correct argument names
+argument-rgx=[a-z_][a-z0-9_]{2,30}$
+
+# Regular expression which should only match correct variable names
+variable-rgx=[a-z_][a-z0-9_]{2,30}$
+
+# Regular expression which should only match correct attribute names in class
+# bodies
+class-attribute-rgx=([A-Za-z_][A-Za-z0-9_]{2,30}|(__.*__))$
+
+# Regular expression which should only match correct list comprehension /
+# generator expression variable names
+inlinevar-rgx=[A-Za-z_][A-Za-z0-9_]*$
+
+# Good variable names which should always be accepted, separated by a comma
+# f is a useful name for a file descriptor
+good-names=f,i,j,k,ex,Run,_
+
+# Bad variable names which should always be refused, separated by a comma
+bad-names=foo,bar,baz,toto,tutu,tata
+
+# Regular expression which should only match function or class names that do
+# not require a docstring.
+no-docstring-rgx=__.*__
+
+# Minimum line length for functions/classes that require docstrings, shorter
+# ones are exempt.
+docstring-min-length=-1
+
+
+[VARIABLES]
+
+# Tells whether we should check for unused import in __init__ files.
+init-import=no
+
+# A regular expression matching the beginning of the name of dummy variables
+# (i.e. not used).
+dummy-variables-rgx=_$|dummy
+
+# List of additional names supposed to be defined in builtins. Remember that
+# you should avoid to define new builtins when possible.
+additional-builtins=
+
+
+[FORMAT]
+
+# Maximum number of characters on a single line.
+max-line-length=79
+
+# Regexp for a line that is allowed to be longer than the limit.
+ignore-long-lines=^\s*(# )?<?https?://\S+>?$
+
+# Maximum number of lines in a module
+max-module-lines=1000
+
+# String used as indentation unit. This is usually " " (4 spaces) or "\t" (1
+# tab).
+indent-string='    '
+
+
+[TYPECHECK]
+
+# Tells whether missing members accessed in mixin class should be ignored. A
+# mixin class is detected if its name ends with "mixin" (case insensitive).
+ignore-mixin-members=yes
+
+# List of classes names for which member attributes should not be checked
+# (useful for classes with attributes dynamically set).
+ignored-classes=SQLObject
+
+# When zope mode is activated, add a predefined set of Zope acquired attributes
+# to generated-members.
+zope=no
+
+# List of members which are set dynamically and missed by pylint inference
+# system, and so shouldn't trigger E0201 when accessed. Python regular
+# expressions are accepted.
+generated-members=REQUEST,acl_users,aq_parent
+
+
+[CLASSES]
+
+# List of interface methods to ignore, separated by a comma. This is used for
+# instance to not check methods defines in Zope's Interface base class.
+ignore-iface-methods=isImplementedBy,deferred,extends,names,namesAndDescriptions,queryDescriptionFor,getBases,getDescriptionFor,getDoc,getName,getTaggedValue,getTaggedValueTags,isEqualOrExtendedBy,setTaggedValue,isImplementedByInstancesOf,adaptWith,is_implemented_by
+
+# List of method names used to declare (i.e. assign) instance attributes.
+defining-attr-methods=__init__,__new__,setUp
+
+# List of valid names for the first argument in a class method.
+valid-classmethod-first-arg=cls
+
+# List of valid names for the first argument in a metaclass class method.
+valid-metaclass-classmethod-first-arg=mcs
+
+
+[IMPORTS]
+
+# Deprecated modules which should not be used, separated by a comma
+deprecated-modules=regsub,TERMIOS,Bastion,rexec
+
+# Create a graph of every (i.e. internal and external) dependencies in the
+# given file (report RP0402 must not be disabled)
+import-graph=
+
+# Create a graph of external dependencies in the given file (report RP0402 must
+# not be disabled)
+ext-import-graph=
+
+# Create a graph of internal dependencies in the given file (report RP0402 must
+# not be disabled)
+int-import-graph=
+
+
+[DESIGN]
+
+# Maximum number of arguments for function / method
+max-args=5
+
+# Argument names that match this expression will be ignored. Default to name
+# with leading underscore
+ignored-argument-names=_.*
+
+# Maximum number of locals for function / method body
+max-locals=15
+
+# Maximum number of return / yield for function / method body
+max-returns=6
+
+# Maximum number of branch for function / method body
+max-branches=12
+
+# Maximum number of statements in function / method body
+max-statements=50
+
+# Maximum number of parents for a class (see R0901).
+max-parents=7
+
+# Maximum number of attributes for a class (see R0902).
+max-attributes=7
+
+# Minimum number of public methods for a class (see R0903).
+min-public-methods=2
+
+# Maximum number of public methods for a class (see R0904).
+max-public-methods=20
+
+
+[EXCEPTIONS]
+
+# Exceptions that will emit a warning when being caught. Defaults to
+# "Exception"
+overgeneral-exceptions=Exception