Easy, Fast, Cheap Way to Generate CPU Load?

jsailor asks: "A large client and their engineering team will be evaluating cabinets and their ability to cool high density blade server deployments. Some of these systems can consume upward of 21 kW per rack and accordingly require a lot of airflow and/or liquid systems to cool. The systems actively monitor heat conditions, increase airflow rates, and can throttle CPU speeds if necessary. What we need is an easy, fast, and cheap way to run the 2-way and 4-way blades at or near peak CPU utilization for extended periods of time so thermal analysis can be performed. Ideally, we would be able to boot them off a CD and have some means of monitoring the CPU on each or even setting the level of CPU utilization we'd like them to run at. Please note that we do NOT need to simulate a real world application and disk and network access are not of much concern. While running your favorite compute-intensive project is a nice idea, we need something simple so I've come to the Slashdot community for assistance. What are your thoughts?"

Comments

How about these?

[brejc8]

CPU Burn-in and cpuburn

Re:How about these?

[GoRK]

I was going to suggest these two tools also. They are specifically designed for what you want to do. I use CPU burn exclusively to test cooling performance in new white box server setups; it is particularly useful in conjunction with lmsensors to determine optimum cooling.

The utility is designed to run instruction loops which require the most POWER CONSUMPTION from the cpu and thus generate the most heat. There are versions tuned from pentiums up to current CPU's. There is also a version designed to cause your ram to use the maximum amount of power it can.

Unlike running any old utility that gives you "100% cpu load" such as the comments about running 'true' in an endless loop presented in this thread, cpuburn is actually targeted at generating heat, power, and system stress. 100% processor utalization does not necessarily mean that you are stressing a computer.

Unsuprisingly, many times cpuburn will often cause a computer that you believe is fine and works properly 100% of the time to hard lock after only a couple of minutes. Over time, dust builds up; fans get slower and give out, etc. and a computer with an adequate cooling solution a year ago may not be able to take the heat anymore. CPUBurn can reveal that. It is a very very good utility.

Prime95, as the overclockers use.

[gusnz]

Prime95. Available for numerous OSs.

So simple.

[leonbrooks]

Boot Knoppix, open (BASH) shell, type:

for cpu in 1 2 3 4; do
( while true; do true; done ) &
done

If you want to exercise the disks a bit too, replace the middle line with:

( while true; do find / -type f -exec cp {} /dev/null \; ; done ) &

gzip

[CyberVenom]

So you need simple, fast, no-need-for-network CPU load?

Boot any linux liveCD that supports your hardware, and run the following command:

cat /dev/urandom | gzip > /dev/null

Sould eat one whole CPU and run forever. If you have an SMP machine, run one instance of that per CPU, and you should max out. The system should still remain responsive enough that you can terminate the processes at will, even though the CPU is at 100% usage.

I would try to pick a liveCD that does not bother starting X since that just adds to the boot time.

You may want to consider the heat generated by components other than the CPU. Hard drives put off a significant amount of heat, as do memory and video, and to a lesser extent network hardware.

To utilize a lot of memory as well as CPU, you might look for something like a prime-factoring program. (prime seives love to eat memory)

For video heat, try something like an unlimited framerate demo in Quake 2. (I think there is even a Linux port)

For network load, just use a ping utility that supports flood-ping and arbitrary payloads. Then floodping yourself or something on the LAN with huge packets.

For hard drive heat, you could just dd /dev/zero to a blank HD (since you are booting from CD, destroying the contents of the HD won't crash the OS)

while true; do true; done

[mystran]

That title says it. It's bash syntax. Will give you about 100% CPU utilization on Linux. Run several instances at once to load more CPU's. (while true; do true; done) & (while true; do true; done) & (while true; do true; done) & Since true is /bin/true, each iteration forks twice, which means zero-filling at least a few pages of memory per iteration, which recent Linux AFAIK does with SIMD instructions where possible (someone correct me if that's not correct), so that actually loads more of the CPU core than one would think at first.