#!/usr/bin/python3

# Copyright (C) 2015-2018 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/>.

"""Compare two benchmark results

Given two benchmark result files and a threshold, this script compares the

benchmark results and flags differences in performance beyond a given

threshold.

"""

import sys

import os

import pylab

import import_bench as bench

import argparse

def do_compare(func, var, tl1, tl2, par, threshold):

    """Compare one of the aggregate measurements

    Helper function to compare one of the aggregate measurements of a function

    variant.

    Args:

        func: Function name

        var: Function variant name

        tl1: The first timings list

        tl2: The second timings list

        par: The aggregate to measure

        threshold: The threshold for differences, beyond which the script should

        print a warning.

    """

    d = abs(tl2[par] - tl1[par]) * 100 / tl1[str(par)]

    if d > threshold:

        if tl1[par] > tl2[par]:

            ind = '+++'

        else:

            ind = '---'

        print('%s %s(%s)[%s]: (%.2lf%%) from %g to %g' %

                (ind, func, var, par, d, tl1[par], tl2[par]))

def compare_runs(pts1, pts2, threshold):

    """Compare two benchmark runs

    Args:

        pts1: Timing data from first machine

        pts2: Timing data from second machine

    """

    # XXX We assume that the two benchmarks have identical functions and

    # variants.  We cannot compare two benchmarks that may have different

    # functions or variants.  Maybe that is something for the future.

    for func in pts1['functions'].keys():

        for var in pts1['functions'][func].keys():

            tl1 = pts1['functions'][func][var]

            tl2 = pts2['functions'][func][var]

            # Compare the consolidated numbers

            # do_compare(func, var, tl1, tl2, 'max', threshold)

            do_compare(func, var, tl1, tl2, 'min', threshold)

            do_compare(func, var, tl1, tl2, 'mean', threshold)

            # Skip over to the next variant or function if there is no detailed

            # timing info for the function variant.

            if 'timings' not in pts1['functions'][func][var].keys() or \

                'timings' not in pts2['functions'][func][var].keys():

                    return

            # If two lists do not have the same length then it is likely that

            # the performance characteristics of the function have changed.

            # XXX: It is also likely that there was some measurement that

            # strayed outside the usual range.  Such ouiers should not

            # happen on an idle machine with identical hardware and

            # configuration, but ideal environments are hard to come by.

            if len(tl1['timings']) != len(tl2['timings']):

                print('* %s(%s): Timing characteristics changed' %

                        (func, var))

                print('\tBefore: [%s]' %

                        ', '.join([str(x) for x in tl1['timings']]))

                print('\tAfter: [%s]' %

                        ', '.join([str(x) for x in tl2['timings']]))

                continue

            # Collect numbers whose differences cross the threshold we have

            # set.

            issues = [(x, y) for x, y in zip(tl1['timings'], tl2['timings']) \

                        if abs(y - x) * 100 / x > threshold]

            # Now print them.

            for t1, t2 in issues:

                d = abs(t2 - t1) * 100 / t1

                if t2 > t1:

                    ind = '-'

                else:

                    ind = '+'

                print("%s %s(%s): (%.2lf%%) from %g to %g" %

                        (ind, func, var, d, t1, t2))

def plot_graphs(bench1, bench2):

    """Plot graphs for functions

    Make scatter plots for the functions and their variants.

    Args:

        bench1: Set of points from the first machine

        bench2: Set of points from the second machine.

    """

    for func in bench1['functions'].keys():

        for var in bench1['functions'][func].keys():

            # No point trying to print a graph if there are no detailed

            # timings.

            if u'timings' not in bench1['functions'][func][var].keys():

                print('Skipping graph for %s(%s)' % (func, var))

                continue

            pylab.clf()

            pylab.ylabel('Time (cycles)')

            # First set of points

            length = len(bench1['functions'][func][var]['timings'])

            X = [float(x) for x in range(length)]

            lines = pylab.scatter(X, bench1['functions'][func][var]['timings'],

                    1.5 + 100 / length)

            pylab.setp(lines, 'color', 'r')

            # Second set of points

            length = len(bench2['functions'][func][var]['timings'])

            X = [float(x) for x in range(length)]

            lines = pylab.scatter(X, bench2['functions'][func][var]['timings'],

                    1.5 + 100 / length)

            pylab.setp(lines, 'color', 'g')

            if var:

                filename = "%s-%s.png" % (func, var)

            else:

                filename = "%s.png" % func

            print('Writing out %s' % filename)

            pylab.savefig(filename)

def main(bench1, bench2, schema, threshold):

    bench1 = bench.parse_bench(bench1, schema)

    bench2 = bench.parse_bench(bench2, schema)

    plot_graphs(bench1, bench2)

    bench.compress_timings(bench1)

    bench.compress_timings(bench2)

    compare_runs(bench1, bench2, threshold)

if __name__ == '__main__':

    parser = argparse.ArgumentParser(description='Take two benchmark and compare their timings.')

    # Required parameters

    parser.add_argument('bench1', help='First bench to compare')

    parser.add_argument('bench2', help='Second bench to compare')

    # Optional parameters

    parser.add_argument('--schema',

                        default=os.path.join(os.path.dirname(os.path.realpath(__file__)),'benchout.schema.json'),

                        help='JSON file to validate source/dest files (default: %(default)s)')

    parser.add_argument('--threshold', default=10.0, help='Only print those with equal or higher threshold (default: %(default)s)')

    args = parser.parse_args()

    main(args.bench1, args.bench2, args.schema, args.threshold)