~linaro-toolchain-dev/cortex-strings/trunk

#!/usr/bin/env python

"""Simple harness that benchmarks different variants of the routines,

caches the results, and emits all of the records at the end.

Results are generated for different values of:

 * Source

 * Routine

 * Length

 * Alignment

"""

import subprocess

import math

import sys

# Prefix to the executables

build = '../build/try-'

ALL = 'memchr memcmp memcpy memset strchr strcmp strcpy strlen'

HAS = {

    'this': 'bounce memchr memcpy memset strchr strcpy strlen',

    'bionic': 'memcmp memcpy memset strcmp strcpy strlen',

    'bionic-c': ALL,

    'csl': 'memcpy memset',

    'glibc': 'memcpy memset strlen',

    'glibc-c': ALL,

    'newlib': 'memcpy strcmp strcpy strlen',

    'newlib-c': ALL,

    'newlib-xscale': 'memchr memcpy memset strchr strcmp strcpy strlen',

    'plain': 'memset memcpy strcmp strcpy',

}

def run(cache, variant, function, bytes, loops, alignment=8, quiet=False):

    """Perform a single run, exercising the cache as appropriate."""

    key = ':'.join('%s' % x for x in (variant, function, bytes, loops, alignment))

    if key in cache:

        got = cache[key]

    else:

        xbuild = build

        cmd = '%(xbuild)s%(variant)s -t %(function)s -c %(bytes)s -l %(loops)s -a %(alignment)s' % locals()

        try:

            got = subprocess.check_output(cmd.split()).strip()

        except OSError, ex:

            assert False, 'Error %s while running %s' % (ex, cmd)

    parts = got.split(':')

    took = float(parts[5])

    cache[key] = got

    if not quiet:

        print got

        sys.stdout.flush()

    return took

def run_many(cache, variants, bytes, alignments):

    # We want the data to come out in a useful order.  So fix an

    # alignment and function, and do all sizes for a variant first

    bytes = sorted(bytes)

    mid = bytes[len(bytes)/2]

    # Use the ordering in 'this' as the default

    all_functions = HAS['this'].split()

    # Find all other functions

    for functions in HAS.values():

        for function in functions.split():

            if function not in all_functions:

                all_functions.append(function)

    for alignment in alignments:

        for function in all_functions:

            for variant in variants:

                if function not in HAS[variant].split():

                    continue

                # Run a tracer through and see how long it takes and

                # adjust the number of loops based on that.  Not great

                # for memchr() and similar which are O(n), but it will

                # do

                f = 50000000

                want = 5.0

                loops = int(f / math.sqrt(max(1, mid)))

                took = run(cache, variant, function, mid, loops, alignment, quiet=True)

                # Keep it reasonable for silly routines like bounce

                factor = min(20, max(0.05, want/took))

                f = f * factor

                # Round f to a few significant figures

                scale = 10**int(math.log10(f) - 1)

                f = scale*int(f/scale)

                for b in sorted(bytes):

                    # Figure out the number of loops to give a roughly consistent run

                    loops = int(f / math.sqrt(max(1, b)))

                    run(cache, variant, function, b, loops, alignment)

def run_top(cache):

    variants = sorted(HAS.keys())

    # Upper limit in bytes to test to

    top = 512*1024

    # Test all powers of 2

    step1 = 2.0

    # Test intermediate powers of 1.4

    step2 = 1.4

    bytes = []

    for step in [step1, step2]:

        if step:

            # Figure out how many steps get us up to the top

            steps = int(round(math.log(top) / math.log(step)))

            bytes.extend([int(step**x) for x in range(0, steps+1)])

    alignments = [8, 16, 4, 1, 2, 32]

    run_many(cache, variants, bytes, alignments)

def main():

    cachename = 'cache.txt'

    cache = {}

    try:

        with open(cachename) as f:

            for line in f:

                line = line.strip()

                parts = line.split(':')

                cache[':'.join(parts[:5])] = line

    except:

        pass

    try:

        run_top(cache)

    finally:

        with open(cachename, 'w') as f:

            for line in sorted(cache.values()):

                print >> f, line

if __name__ == '__main__':

    main()