The Fhlushstone Page

Formerly the /dev/null benchmark

Terribly Exciting Fhlushstone News

Friday 4 February - there are now 693 results in the Fhlushstone database, most of which are even valid. The ones which aren't just won't be shown in the stats, so there. But we still need more! More! Keep 'em coming. Tell your friends. Benchmark your Commodore 64! Your cellphone! Your coffee machine! Hell, they all run Linux or NetBSD now, right? Coming soon - select results by OS, machine, whatever, and maybe (depending on how the weekend goes) some actual analysis. Thanks, too, to the folks at LWN for the "Linux Link of the Week" accolade. Next stop Slashdot, eh?

Sunday 30 January - jeez, I go away for a couple of days, the page gets mentioned in NTK and of course, the CGIs break. You can stop mailing me now - it wasn't anything to do with permissions, it was broken by an Apache upgrade.

Monday 24 January - gosh, this page was link of the day over at User Friendly yesterday. The proof is here - what, me, honoured? Oh, and you can now see sorted results. Woohoo.


Most benchmarks today are effectively random numbers, so I thought I'd make my very own random number generator to measure the most important performance indicator of any UNIX machine - the throughput of the null device. Machines with a fast /dev/null can discard unread mail, ignore uninteresting log messages and shred incoming user queries with efficient speed, thus leaving more time for harried system administrators to spend on important things like system upgrades and account deletions.


I need your help!

I intend to build a Really Useful Database of machines, operating systems, and the important benchmark time taken to execute:

time dd if=/dev/zero of=/dev/null count=1000000 bs=1k

This is the time taken to copy one million blocks of one kilobyte each from the zero device (a source of zeroes) to the null device (the death of bits, the bit bucket, the eater of words), and is, of course, the only true and genuine performance measure any sysadmin should ever care about. Being able to shred information at great speeds is what computers are primarily for, anyway. The observant will spot that in most cases, what this really measures is the performance of /dev/zero - producing reams of useless data is a much slower operation than destroying said data. However, as the purpose of this benchmark is to be a useless and meaningless benchmark, I figure that anything which can increase the uselessness of it has to be a good thing.


Wow! This sounds great! How can I take part?

Hey, it's easy! Anybody can do it! Just log into your Unix machine, or any machine which looks like Unix, and execute the time dd command mentioned in the last section. Wait a while - anything from a few seconds to, er, a very long time in the case of slower machines. Eventually, it'll return something like:

1000000+0 records in
1000000+0 records out

real    0m56.264s
user    0m6.860s
sys     0m47.470s

This is the time taken to execute the command - the real time elapsed, time spent in user mode, and time spent in the kernel Take the "real" entry and write it down, then fill in the form below and submit. Yes, my HTML's pretty bad, and my form design is even worse, but just think of it as being.. starkly functional, okay?

If you get funny results from this.. it's likely that your shell might have a "time" builtin that's being run rather than the system's "time" utility. I know the C shell does, and it's not unlikely that others might as well. Try running time with the full path (/bin/time or wherever) rather than just time", and this should have the desired effect.

To cite this benchmark, simply boast to everybody you meet that your machine has (for the example above) "56.264 Fhlushstones", and watch them bow down before the mighty data-destroying power of your hardware. Or whatever.

Please note - in seriousness, only run this if you know you're allowed to. It puts a certain amount of load on any machine, and you might annoy other users and, worse, your system administrators if you do it. I don't accept responsibility for damage caused, jobs lost, or anything nasty that happens if you run this command. Not that it's very probable that nasty things will happen, but you never know.


Where are the results? What kind of idiot are you?

You can see the raw results right here, or the ordered results (slow, but working). The pattern is very obvious - Linux is very fast. Some people in the know have sent me mail explaining this - I'll add some information around here with the full story at some point. In summary, Linux may cheat slightly. Doesn't stop it being very fast at ignoring data, though.


So where's this form, then?

Right here. Enjoy. If you have any interesting results or observations concerning this, ahem, benchmark, then let me know - address at the bottom of the page. Oh, and read the options before writing in something else - what you're looking for might well be in the picklist already. Sorting things is a pain if there are umpteen different "Other" for something that's in the picklist already.

Colour: Beige Not Beige Other Manufacturer:
Or Other:
Model name:
CPU/Architecture:
Or other CPU:
Clock speed (MHz):
Number of CPUs:
Installed RAM (in MB):
Operating system:
Or other OS:
(Linux variants are all Linux - distribution doesn't matter)
Kernel version:
Your email address (optional): Time taken: (the "real" field, in seconds)
Include the bits after the decimal point!

Thanks to: The L-Space crowd for inspriring this ridiculousness, Rob Collier for some nifty sanity-checking code, and to Melissa Binde for pointing out that to be a real benchmark it should be "Fhlushstone", not "Flushstone"..


Disclaimer: This study, and the results from it, are merely a joke. Do not take them seriously. Like, really. If you buy computers on the basis of this kind of benchmark you're a very silly person, so don't complain at me about it. This page is Copyright © 2000 by Mike Knell. All rights reserved. The data collected from this page may not be used for anything at all other than personal amusement and research without prior permission. So fingers off.
You could go back to the home page. Alternatively, my boring writings page is here, including the very long and possibly inaccurate Gross Gains and Net Losses. Funnier stuff is here.

Mike Knell, mpk@lspace.org

Last revised Fri Feb 4 20:14:12 GMT 2000
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