Slashdot Mirror
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?"
CPU Burn-in and cpuburn
Mouse powered Chips, Open source Processors and Lego
maybe a simple script like:
#!/bin/sh
sh $0
or in c
while ( 1 )
fork();
William of Ockham had no beard. The most likely explanation is that it was chewed off by squirrels every morning.
Always do it for me. The Vonage ones are the best, especially when you end up with like three of them on a page. Sometimes I swear they can even spike the cpu load of other machines in the same room.
Quantum materiae materietur marmota monax si marmota monax materiam possit materiari?
Post the address on slashdot.
Distributed.Net always shows me what happens to a PC permanently at 100% CPU load. Had to remove it from the student labs because it caused all the Dells to turn their fans up full. The noise! There are ports for pretty much everything.
Fire off one of these per processor:
...]
> while true ; do openssl speed ; done
Doing md2 for 3s on 16 size blocks: 511846 md2's in 3.00s
Doing md2 for 3s on 64 size blocks: 278228 md2's in 3.00s
Doing md2 for 3s on 256 size blocks: 98836 md2's in 3.00s
Doing md2 for 3s on 1024 size blocks: 27645 md2's in 3.00s
Doing md2 for 3s on 8192 size blocks: 3574 md2's in 3.01s
[... continues
-molo
Using your sig line to advertise for friends is lame.
Run seti@home, folding@home, and distributed.net all at once. That should really go for them. Plus they are all linux compatible as well as windows.
Finally...a REAL use for Gentoo
Prime95. Available for numerous OSs.
<!-- DHTML / JavaScript menu, popup tooltip, Ajax scripts -->
http://www.microsoft.com/windows/
Back in the day, the old MS-DOS editing program, EDIT.COM, ran a polling loop that would drive the CPU up to 100%.
The Intel guys used to recommend it as a way to stress test your system.
md5sum < /dev/urandom
/dev/urandom produces an infinite stream of random data - just pipe that throgh MD5 for some nice numerical CPU load. Not disk- or network-bound either.
Boot Knoppix, open (BASH) shell, type:
/dev/null \; ; done ) &
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 {}
Got time? Spend some of it coding or testing
So you need simple, fast, no-need-for-network CPU load?
/dev/urandom | gzip > /dev/null
/dev/zero to a blank HD (since you are booting from CD, destroying the contents of the HD won't crash the OS)
Boot any linux liveCD that supports your hardware, and run the following command:
cat
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
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.
Software should be free as in speech, but if we also get some free beer, all the better.
Modern CPUs are complicated beasts, with multiple execution units, deep pipelines and big caches. And they're connected to big external memories and disk drive arrays. If you want to stress-test the cooling system, then you need code that keeps all the execution units and all the pipelines and the caches and main memory and the disk array all going full blast. That's not as easy as it sounds. Intel has mentioned various test programs that they use when thermally testing their CPUs, but I don't know that they've ever released them. Perhaps they're afraid they'd might cause damage, and they'd have to deal with a lot of irate customers.
Oh, Slashdot, why are you so placid and intolerant of a good old-fashioned flamewar these days? I had to scroll through two pages of boring serious answers before finding this, the proper reply to this story.