% ![](img/timedexec/banner.jpg) TimedExec – README % by LoRd_MuldeR <> | Introduction ============ **TimedExec** is a small utility for *benchmarking* command-line programs. It will *execute* the specified program with the specified command-line arguments and then *measure* the time that it takes for the execution to complete. In order to obtain *accurate* results, all measurements are implemented via *high-resolution* performance timers. And, since program execution times unavoidably are subject to certain variations (e.g. due to environmental noise), each test will be repeated *multiple* times. The number of metering passes can be configured as desired. Optionally, a number of "warm-up" passes can be performed *prior to* the first metering pass. The warm-up passes prevent caching effects from interfering with the execution times. TimedExec will then compute the ***mean*** execution time as well as the ***median*** execution time of all metering passes. It will also record the *fastest* and *slowest* execution time that has been measured. Furthermore, TimedExec computes the *standard error* in order to determine ***confidence intervals*** from the benchmarking results^[[Konfidenzintervalle so einfach wie möglich erklärt](http://www.uni-siegen.de/phil/sozialwissenschaften/soziologie/mitarbeiter/ludwig-mayerhofer/statistik/statistik_downloads/konfidenzintervalle.pdf)]. These are the *ranges* which contain the program's “real” average execution time (expected value), *with very high probability*. All results will be saved to a log file. Usage Instructions ================== *TimedExec* uses a very simple command-line syntax. Just type **`TimedExec`**, followed by the program that you want to benchmark. Optionally, any number arguments can be appended; these parameters will be passed to the program. ***Note:*** Some options that influence the behavior of TimedExec can be controlled via environment variables. ``` =============================================================================== Timed Exec - Benchmarking Utility, Version 1.03 Copyright (c) 2018 LoRd_MuldeR . Some rights reserved. This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License . Note that this program is distributed with ABSOLUTELY NO WARRANTY. =============================================================================== Usage: TimedExec.exe [Arguments] Influential environment variables: TIMED_EXEC_PASSES - Number of execution passes (default: 5) TIMED_EXEC_WARMUP_PASSES - Number of warm-up passes (default: 1) TIMED_EXEC_LOGFILE - Log-File Name (default: "TimedExec.log") TIMED_EXEC_NO_CHECKS - Set this to *disable* exit code checks ``` Usage Example ------------- In the following example we use *TimedExec* to benchmark the program **`ping.exe`** with the arguments **`-n 12 www.google.com`**. By default, the command will be executed *five* times, preceded by a single "warm-up" pass: ``` TimedExec.exe C:\Windows\System32\ping.exe -n 12 www.google.com ``` Results ======= The resulting output, after all metering passes have been completed, looks like this: ``` =============================================================================== TEST COMPLETED SUCCESSFULLY AFTER 5 METERING PASSES ------------------------------------------------------------------------------- Mean Execution Time : 11.257 seconds Median Execution Time : 11.255 seconds 90% Confidence Interval : +/- 0.006 (0.053%) = [11.251, 11.263] seconds 95% Confidence Interval : +/- 0.007 (0.063%) = [11.250, 11.264] seconds 99% Confidence Interval : +/- 0.009 (0.083%) = [11.248, 11.266] seconds Standard Deviation : 0.007 seconds Standard Error : 0.004 seconds Fastest / Slowest Pass : 11.253 / 11.270 seconds =============================================================================== ``` Interpretation -------------- When comparing measurement results, the ***mean*** (average) execution time may seem like the most obvious choice. However, it has to be noted that the *mean* of a data sample is highly sensitive to “outliers” and therefore can be misleading! This is especially true, when there exists a lot of variation in the data sample. Consequently, comparing the ***median*** execution times usually is the preferable choice. That is because the *median* of a data sample is much more robust against outliers. Furthermore, it is important to keep in mind that the *mean* (or *median*) execution time computed from a limited number of metering passes only yields an ***estimate*** of the program's “real” average execution time (expected value). The “real” value can only be determined accurately from an *infitinte* number of metering passes – which is **not** possible in practice. In this situation, we can have a look at the ***confidence intervals***. These intervals contain the “real” value, *with very high probability*. The most commonly used *confidence interval* is the “95%” one (higher confidence means broader interval, and vice versa). Simply put, as long as the confidence intervals of program A and program B *overlap* (at least partially), we **must not** conclude that either of these programs runs faster (or slower) in the average case. ***No*** conclusion can be drawn in that case! Sources ======= The *TimedExec* source codes are managed by [**Git**](http://git-scm.com/doc) and are available from one of the official mirrors: * https://github.com/lordmulder/TimedExec.git ([Browse](https://github.com/lordmulder/TimedExec)) * https://bitbucket.org/muldersoft/timedexec.git ([Browse](https://bitbucket.org/muldersoft/timedexec)) * https://gitlab.com/timedexec/timedexec.git ([Browse](https://gitlab.com/timedexec/timedexec)) License ======= TimedExec is released under the terms of the [GNU General Public License](http://www.gnu.org/licenses/gpl-2.0.html), version 2. ``` Timed Exec - Command-Line Benchmarking Utility Copyright (c) 2018 LoRd_MuldeR . Some rights reserved. 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, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. http://www.gnu.org/licenses/gpl-2.0.txt ```
**e.o.f.**