cpuburn 1.4

WARNING:
This program is designed to heavily load CPU chips. Undercooled, overclocked or otherwise weak systems may fail causing data loss (filesystem corruption) and possibly permanent damage to electronic components. Nor will it catch all flaws.
USE AT YOUR OWN RISK

CPU testing utilities in optimized assembler for maximum loading P6 (Intel Pentium Pro/II/III and Celeron TM), AMD K7 (Athlon/Duron/Thunderbird TM) AMD K6, and Intel P5 Pentium chips. This is free software, copyright but freely licenced under the GNU Public Licence copyleft.

These programs are designed to load x86 CPUs as heavily as possible for the purposes of system testing. They have been optimized for different processors. FPU and ALU instructions are coded an assembler endless loop. They do not test every instruction. The goal has been to maximize heat production from the CPU, putting stress on the CPU itself, cooling system, motherboard (especially voltage regulators) and power supply
(likely cause of burnBX/MMX errors).

burnP5 is optimized for Intel Pentium w&w/o MMX processors
P6 is for Intel PentiumPro, PentiumII&III and Celeron CPUs
K6 is for AMD K6 processors
K7 is for AMD Athlon/Duron processors
MMX is to test cache/memory interfaces on all CPUs with MMX
BX is an alternate cache/memory test for Intel CPUs

TO USE: root priviliges are NOT required. It has been designed for ELF Linux, but also tested under FreeBSD. and a.out. Burn Testing is best done from a ramdisk distribution (tomsrtbt) or with filesystems unmounted or mounted read-only.

untar the source in a convenient directory:
`tar zxf cpuburn`

compile excutables
`make`

run desired program in background [ _repeat_ for SMP]:
`burnP6 || echo $? &`

Monitor progress of cpuburn by `ps`. When finished, `kill` the burn* process(es). If you have temperature probes (fingers) or the lm-sensors package, you can check your CPU temperature and/or system voltages.

If an error occurs in calculations, it will be preserved, and the program will terminate with error code 254 for an integer/memory error, and error code 255 for a FP/MMX error. Error checking happens every 10-40 sec for burnP6/K6/K7 and I havent seen any CPU errors in testing [lockups occur first]. burnBX and burnMMX check for error every 512 MB (4-10 sec), and error termination is frequently seen, lockups are rarer.

burnBX and burnMMX are essentially very intense RAM testers. They can also take an optional parameter indicating the RAM size to be tested:

A = 2 kB E = 32 kB I = 512 kB M = 8 MB
B = 4 F = 64 J = 1 MB N = 16
C = 8 G = 128 K = 2 O = 32
D = 16 H = 256 L = 4 P = 64

`burnBX L` (4 MB) and `burnMMX F` (64 kB) are the default sizes. A-E mostly test L1 cache, F-H test L2 cache, and H-P force their way to RAM. But even A-E will have some cacheline writeouts to RAM.

In spite of its name, burnBX can be run on any chipset [RAM controller] and tests alot more than the RAM controller. Unfortunately, burnBX is not optimal on AMD processors. burnMMX is preferable for any CPU that has an MMX unit.

burnBX/MMX needs about 72 MB of total RAM + swap to start (not necessarily free), but doesnt use this much unless you request it. They will throw a `Sig 11` if you dont have enough swap.

If you dont want to add more, you can adjust the .bss section downward as indicated in the source comments. They can also test swap, and at least on my system, I can run 2*`burnBX 8` with 128 MB SDRAM with some use of swap, but no excessive thrashing[seeks]. YMMV.

If sub-spec, your system may lock up after 2-10 minutes. It shouldnt. burn* are just an unpriviliged user processes. But it probably means your CPU is undercooled, most likely no thermal grease or other interface material between CPU & heatsink. Or some other deficiency. A power cycle should reset the system. But you should fix it.