How We Benchmark Freecell Solver (Version 1)

sudo_renice is a shell wrapper for nice and ionice that runs the command under optimal resource utilisation. This way it runs faster and gives less variance in the results.

It is reproduced here:

#!/bin/bash
sudo nice -n-20 ionice -c1 -n0 sudo -u "$USER" "$@"

It is important to run both the "before" and "after" versions of the benchmark on the same physical computer, with the same system installation and in similar conditions - one after the other.

We noticed that running an X environment with a resource-heavy desktop environment such as KDE Plasma, can slow down the program and skew the result. As a result, it is a good idea to stop X and use a virtual console or a remote shell such as ssh, and use a process monitor such as htop to make sure nothing else that consumes CPU or RAM is running (such as system services or daemons, or stale processes that were not killed).

We noticed that once the computer becomes overheated, the CPU is being throttled and performance decreases. Make sure this is not the case by making use of the "sensors" command from lm_sensors, PowerTOP, and perhaps by waiting a little using the UNIX sleep command.

Keep track of the results, and try to see which are generally (minimally, on average, etc.) faster. Also see some previous discussion of it on the Linux-IL mailing list.

You should build both versions using CPU flags for maximal performance such as -O3, -march=native, -flto, -fwhole-program, and possibly -fomit-frame-pointer. Profile-guided optimization may prove useful as well.

One should link against a fast malloc library. TCMalloc is the best performer for us, but your kilometrage may vary. Other prominent mallocs, which are not mentioned in the first link, are the Lockless Inc. one and ltalloc