Python script that locates the commit that caused a performance
degradation or improvement in QEMU using the git bisect command
(binary search).
Syntax:
bisect.py [-h] -s,--start START [-e,--end END] [-q,--qemu QEMU] \
--target TARGET --tool {perf,callgrind} -- \
<target executable> [<target executable options>]
[-h] - Print the script arguments help message
-s,--start START - First commit hash in the search range
[-e,--end END] - Last commit hash in the search range
(default: Latest commit)
[-q,--qemu QEMU] - QEMU path.
(default: Path to a GitHub QEMU clone)
--target TARGET - QEMU target name
--tool {perf,callgrind} - Underlying tool used for measurements
Example of usage:
bisect.py --start=fdd76fecdd --qemu=/path/to/qemu --target=ppc \
--tool=perf -- coulomb_double-ppc -n 1000
Example output:
Start Commit Instructions: 12,710,790,060
End Commit Instructions: 13,031,083,512
Performance Change: -2.458%
Estimated Number of Steps: 10
*****************BISECT STEP 1*****************
Instructions: 13,031,097,790
Status: slow commit
*****************BISECT STEP 2*****************
Instructions: 12,710,805,265
Status: fast commit
*****************BISECT STEP 3*****************
Instructions: 13,031,028,053
Status: slow commit
*****************BISECT STEP 4*****************
Instructions: 12,711,763,211
Status: fast commit
*****************BISECT STEP 5*****************
Instructions: 13,031,027,292
Status: slow commit
*****************BISECT STEP 6*****************
Instructions: 12,711,748,738
Status: fast commit
*****************BISECT STEP 7*****************
Instructions: 12,711,748,788
Status: fast commit
*****************BISECT STEP 8*****************
Instructions: 13,031,100,493
Status: slow commit
*****************BISECT STEP 9*****************
Instructions: 12,714,472,954
Status: fast commit
****************BISECT STEP 10*****************
Instructions: 12,715,409,153
Status: fast commit
****************BISECT STEP 11*****************
Instructions: 12,715,394,739
Status: fast commit
*****************BISECT RESULT*****************
commit 0673ecdf6cb2b1445a85283db8cbacb251c46516
Author: Richard Henderson <richard.hender...@linaro.org>
Date: Tue May 5 10:40:23 2020 -0700
softfloat: Inline float64 compare specializations
Replace the float64 compare specializations with inline functions
that call the standard float64_compare{,_quiet} functions.
Use bool as the return type.
***********************************************
Signed-off-by: Ahmed Karaman <ahmedkhaledkara...@gmail.com>
---
scripts/performance/bisect.py | 374 ++++++++++++++++++++++++++++++++++
1 file changed, 374 insertions(+)
create mode 100755 scripts/performance/bisect.py
diff --git a/scripts/performance/bisect.py b/scripts/performance/bisect.py
new file mode 100755
index 0000000000..869cc69ef4
--- /dev/null
+++ b/scripts/performance/bisect.py
@@ -0,0 +1,374 @@
+#!/usr/bin/env python3
+
+# Locate the commit that caused a performance degradation or improvement in
+# QEMU using the git bisect command (binary search).
+#
+# Syntax:
+# bisect.py [-h] -s,--start START [-e,--end END] [-q,--qemu QEMU] \
+# --target TARGET --tool {perf,callgrind} -- \
+# <target executable> [<target executable options>]
+#
+# [-h] - Print the script arguments help message
+# -s,--start START - First commit hash in the search range
+# [-e,--end END] - Last commit hash in the search range
+# (default: Latest commit)
+# [-q,--qemu QEMU] - QEMU path.
+# (default: Path to a GitHub QEMU clone)
+# --target TARGET - QEMU target name
+# --tool {perf,callgrind} - Underlying tool used for measurements
+
+# Example of usage:
+# bisect.py --start=fdd76fecdd --qemu=/path/to/qemu --target=ppc --tool=perf \
+# -- coulomb_double-ppc -n 1000
+#
+# This file is a part of the project "TCG Continuous Benchmarking".
+#
+# Copyright (C) 2020 Ahmed Karaman <ahmedkhaledkara...@gmail.com>
+# Copyright (C) 2020 Aleksandar Markovic <aleksandar.qemu.de...@gmail.com>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import argparse
+import multiprocessing
+import tempfile
+import os
+import shutil
+import subprocess
+import sys
+
+
+############################ GIT WRAPPERS ############################
+def git_bisect(qemu_path, command, args=None):
+ """
+ Wrapper function for running git bisect.
+
+ Parameters:
+ qemu_path (str): QEMU path.
+ command (str): bisect command (start|fast|slow|reset).
+ args (list): Optional arguments.
+
+ Returns:
+ (str): git bisect stdout.
+ """
+ process = ["git", "bisect", command]
+ if args:
+ process += args
+ bisect = subprocess.run(process,
+ cwd=qemu_path,
+ stdout=subprocess.PIPE,
+ stderr=subprocess.PIPE)
+ if bisect.returncode:
+ sys.exit(bisect.stderr.decode("utf-8"))
+ return bisect.stdout.decode("utf-8")
+
+
+def git_checkout(commit, qemu_path):
+ """
+ Wrapper function for checking out a given git commit.
+
+ Parameters:
+ commit (str): Commit hash of a git commit.
+ qemu_path (str): QEMU path.
+ """
+ checkout_commit = subprocess.run(["git",
+ "checkout",
+ commit],
+ cwd=qemu_path,
+ stdout=subprocess.DEVNULL,
+ stderr=subprocess.PIPE)
+ if checkout_commit.returncode:
+ sys.exit(checkout_commit.stderr.decode("utf-8"))
+
+
+def git_clone(qemu_path):
+ """
+ Wrapper function for cloning QEMU git repo from GitHub.
+
+ Parameters:
+ qemu_path (str): Path to clone the QEMU repo to.
+ """
+ clone_qemu = subprocess.run(["git",
+ "clone",
+ "https://github.com/qemu/qemu.git";,
+ qemu_path],
+ stderr=subprocess.STDOUT)
+ if clone_qemu.returncode:
+ sys.exit("Failed to clone QEMU!")
+######################################################################
+
+
+def check_requirements(tool):
+ """
+ Verify that all script requirements are installed (perf|callgrind & git).
+
+ Parameters:
+ tool (str): Tool used for the measurement (perf or callgrind).
+ """
+ if tool == "perf":
+ check_perf_installation = subprocess.run(["which", "perf"],
+ stdout=subprocess.DEVNULL)
+ if check_perf_installation.returncode:
+ sys.exit("Please install perf before running the script.")
+
+ # Insure user has previllage to run perf
+ check_perf_executability = subprocess.run(["perf", "stat", "ls", "/"],
+ stdout=subprocess.DEVNULL,
+ stderr=subprocess.DEVNULL)
+ if check_perf_executability.returncode:
+ sys.exit("""
+ Error:
+ You may not have permission to collect stats.
+ Consider tweaking /proc/sys/kernel/perf_event_paranoid,
+ which controls use of the performance events system by
+ unprivileged users (without CAP_SYS_ADMIN).
+ -1: Allow use of (almost) all events by all users
+ Ignore mlock limit after perf_event_mlock_kb without CAP_IPC_LOCK
+ 0: Disallow ftrace function tracepoint by users without CAP_SYS_ADMIN
+ Disallow raw tracepoint access by users without CAP_SYS_ADMIN
+ 1: Disallow CPU event access by users without CAP_SYS_ADMIN
+ 2: Disallow kernel profiling by users without CAP_SYS_ADMIN
+ To make this setting permanent, edit /etc/sysctl.conf too, e.g.:
+ kernel.perf_event_paranoid = -1
+
+ *Alternatively, you can run this script under sudo privileges.
+ """)
+ elif tool == "callgrind":
+ check_valgrind_installation = subprocess.run(["which", "valgrind"],
+ stdout=subprocess.DEVNULL)
+ if check_valgrind_installation.returncode:
+ sys.exit("Please install valgrind before running the script.")
+
+ # Insure that git is installed
+ check_git_installation = subprocess.run(["which", "git"],
+ stdout=subprocess.DEVNULL)
+ if check_git_installation.returncode:
+ sys.exit("Please install git before running the script.")
+
+
+def make(qemu_build_path):
+ """
+ Build QEMU by running the Makefile.
+
+ Parameters:
+ qemu_build_path (str): Path to the build directory with configuration
files.
+ """
+ run_make = subprocess.run(["make",
+ "-j",
+ str(multiprocessing.cpu_count())],
+ cwd=qemu_build_path,
+ stdout=subprocess.DEVNULL,
+ stderr=subprocess.PIPE)
+ if run_make.returncode:
+ sys.exit(run_make.stderr.decode("utf-8"))
+
+
+def measure_instructions(tool, qemu_exe_path, command):
+ """
+ Measure the number of instructions when running an program with QEMU.
+
+ Parameters:
+ tool (str): Tool used for the measurement (perf|callgrind).
+ qemu_exe_path (str): Path to the QEMU executable of the equivalent target.
+ command (list): Program path and arguments.
+
+ Returns:
+ (int): Number of instructions.
+ """
+ if tool == "perf":
+ run_perf = subprocess.run((["perf",
+ "stat",
+ "-x",
+ " ",
+ "-e",
+ "instructions",
+ qemu_exe_path]
+ + command),
+ stdout=subprocess.DEVNULL,
+ stderr=subprocess.PIPE)
+ if run_perf.returncode:
+ sys.exit(run_perf.stderr.decode("utf-8"))
+ else:
+ perf_output = run_perf.stderr.decode("utf-8").split(" ")
+ return int(perf_output[0])
+
+ elif tool == "callgrind":
+ with tempfile.NamedTemporaryFile() as tmpfile:
+ run_callgrind = subprocess.run((["valgrind",
+ "--tool=callgrind",
+ "--callgrind-out-file={}".format(
+ tmpfile.name),
+ qemu_exe_path]
+ + command),
+ stdout=subprocess.DEVNULL,
+ stderr=subprocess.PIPE)
+ if run_callgrind.returncode:
+ sys.exit(run_callgrind.stderr.decode("utf-8"))
+ else:
+ callgrind_output = run_callgrind.stderr.decode("utf-8").split("\n")
+ return int(callgrind_output[8].split(" ")[-1])
+
+
+def main():
+ # Parse the command line arguments
+ parser = argparse.ArgumentParser(
+ usage="bisect.py [-h] -s,--start START [-e,--end END] [-q,--qemu QEMU]
"
+ "--target TARGET --tool {perf,callgrind} -- "
+ "<target executable> [<target executable options>]")
+
+ parser.add_argument("-s", "--start", dest="start", type=str, required=True,
+ help="First commit hash in the search range")
+ parser.add_argument("-e", "--end", dest="end", type=str, default="master",
+ help="Last commit hash in the search range")
+ parser.add_argument("-q", "--qemu", dest="qemu", type=str, default="",
+ help="QEMU path")
+ parser.add_argument("--target", dest="target", type=str, required=True,
+ help="QEMU target")
+ parser.add_argument("--tool", dest="tool", choices=["perf", "callgrind"],
+ required=True, help="Tool used for measurements")
+
+ parser.add_argument("command", type=str, nargs="+", help=argparse.SUPPRESS)
+
+ args = parser.parse_args()
+
+ # Extract the needed variables from the args
+ start_commit = args.start
+ end_commit = args.end
+ qemu = args.qemu
+ target = args.target
+ tool = args.tool
+ command = args.command
+
+ # Set QEMU path
+ if qemu == "":
+ # Create a temp directory for cloning QEMU
+ tmpdir = tempfile.TemporaryDirectory()
+ qemu_path = os.path.join(tmpdir.name, "qemu")
+
+ # Clone QEMU into the temporary directory
+ print("Fetching QEMU: ", end="", flush=True)
+ git_clone(qemu_path)
+ print()
+ else:
+ qemu_path = qemu
+
+ # Create the build directory
+ qemu_build_path = os.path.join(qemu_path, "tmp-build-gcc")
+ if not os.path.exists(qemu_build_path):
+ os.mkdir(qemu_build_path)
+ else:
+ sys.exit("A build directory with the same name (tmp-build-gcc) used in
"
+ "the script is already in the provided QEMU path.")
+
+ qemu_exe_path = os.path.join(qemu_build_path,
+ "{}-linux-user".format(target),
+ "qemu-{}".format(target))
+
+ # Configure QEMU
+ configure = subprocess.run(["../configure",
+ "--target-list={}-linux-user".format(target)],
+ cwd=qemu_build_path,
+ stdout=subprocess.DEVNULL,
+ stderr=subprocess.PIPE)
+ if configure.returncode:
+ sys.exit(configure.stderr.decode("utf-8"))
+
+ # Do performance measurements for the start commit
+ git_checkout(start_commit, qemu_path)
+ make(qemu_build_path)
+ start_commit_instructions = measure_instructions(tool,
+ qemu_exe_path,
+ command)
+ print("{:<30} {}".format("Start Commit Instructions:",
+ format(start_commit_instructions, ",")))
+
+ # Do performance measurements for the end commit
+ git_checkout(end_commit, qemu_path)
+ make(qemu_build_path)
+ end_commit_instructions = measure_instructions(tool,
+ qemu_exe_path,
+ command)
+ print("{:<30} {}".format("End Commit Instructions:",
+ format(end_commit_instructions, ",")))
+
+ # Calculate performance difference between start and end commits
+ performance_difference = \
+ (start_commit_instructions - end_commit_instructions) / \
+ max(end_commit_instructions, start_commit_instructions) * 100
+ performance_change = "+" if performance_difference > 0 else "-"
+ print("{:<30} {}".format("Performance Change:",
+ performance_change +
+ str(round(abs(performance_difference), 3))+"%"))
+
+ # Set the custom terms used for progressing in "git bisect"
+ term_old = "fast" if performance_difference < 0 else "slow"
+ term_new = "slow" if term_old == "fast" else "fast"
+
+ # Start git bisect
+ git_bisect(qemu_path, "start", [
+ "--term-old", term_old, "--term-new", term_new])
+ # Set start commit state
+ git_bisect(qemu_path, term_old, [start_commit])
+ # Set end commit state
+ bisect_output = git_bisect(qemu_path, term_new, [end_commit])
+ # Print estimated bisect steps
+ print("\n{:<30} {}\n".format(
+ "Estimated Number of Steps:", bisect_output.split()[9]))
+
+ # Initialize bisect_count to track the number of performed
+ bisect_count = 1
+
+ while True:
+ print("**************BISECT STEP
{}**************".format(bisect_count))
+
+ make(qemu_build_path)
+
+ instructions = measure_instructions(tool, qemu_exe_path, command)
+ # Find the difference between the current instructions and start/end
+ # instructions.
+ diff_end = abs(instructions - end_commit_instructions)
+ diff_start = abs(instructions - start_commit_instructions)
+
+ # If current number of insructions is closer to that of start,
+ # set current commit as term_old.
+ # Else, set current commit as term_new.
+ if diff_end > diff_start:
+ bisect_command = term_old
+ else:
+ bisect_command = term_new
+
+ print("{:<20} {}".format("Instructions:", format(instructions, ",")))
+ print("{:<20} {}".format("Status:", "{}
commit".format(bisect_command)))
+
+ bisect_output = git_bisect(qemu_path, bisect_command)
+
+ # Continue if still bisecting,
+ # else, print result and break.
+ if not bisect_output.split(" ")[0] == "Bisecting:":
+ print("\n*****************BISECT RESULT*****************")
+ commit_message_start = bisect_output.find("commit\n") + 7
+ commit_message_end = bisect_output.find(":040000") - 1
+ print(bisect_output[commit_message_start:commit_message_end])
+ break
+
+ bisect_count += 1
+
+ # Reset git bisect
+ git_bisect(qemu_path, "reset")
+
+ # Delete temp build directory
+ shutil.rmtree(qemu_build_path)
+
+
+if __name__ == "__main__":
+ main()
--
2.17.1
