Energy and Power

And now, here's the million dollar question: did Boston and Calxeda succeed in building a server with a spectacular performance/watt ratio? Judge for yourself.

Webhosting server Energy & Power

Calxeda really did it: each server needs about 8.3W (200W/24), measured at the wall. That is exactly what Calxeda promised: about 6W (at 1.4GHz) per server node (measured internally), up to 8.5W measured at the wall (again at 1.4GHz). That is nothing short of amazing if you consider the performance numbers.

In addition, the use of cpufreq and the downsizing of the server interconnects pays off here: we get 10% lower power on average and 18% lower power when idle. The optimizations are particularly important for the idle power use, where they spell the difference between using slightly more power and slightly less power than the Intel server.

The Results that Matter Pricing and Conclusion
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  • tuxRoller - Tuesday, March 12, 2013 - link

    Why WOULD you expect DVFS to boost performance?
    You seem to think it slightly revelational that the scores are slightly lower (but perhaps statistically meaningless).
    Reply
  • dig23 - Tuesday, March 12, 2013 - link

    On-demand seems fair choice to me, its what best you can do on this OSes. But I will be very interested to see energy efficiency numbers when DVFS working on swarm of ARM nodes...:) Reply
  • tuxRoller - Tuesday, March 12, 2013 - link

    It's not cpu governor I'm talking about but DVFS in particular.
    There's bound to be some small amount of latency involved with the process.
    It's point isn't for best performance but energy efficiency thus why I made the comment in the first place.
    Reply
  • JarredWalton - Tuesday, March 12, 2013 - link

    There's the potential for DVFS to optimize for better performance on a few cores while putting some of the other cores into a lower P-state, but I think that would be more for stuff like Turbo Boost/Turbo Core. It's also possible Johan is referring to the potential for the optimizations to simply improve performance in general. Reply
  • CodyHall - Friday, March 15, 2013 - link

    Love my job, since I've been bringing in $5600… I sit at home, music playing while I work in front of my new iMac that I got now that I'm making it online.(Click Home information)
    http://goo.gl/9u8us
    Reply
  • JohanAnandtech - Wednesday, March 13, 2013 - link

    Can you tell me where I got you confused? Because I write "This allowed us to make use of Dynamic Voltage and Frequency Scaling (DVFS, P-states) using the CPUfreq tool. First let's see if all these power saving tweaks have reduced the total throughput."

    So it should been clear that we are looking for a better performance/watt ratio. The interesting thing to note is that ARM benefits from p-states, and that Intel's excellent implementation of C-states makes p-states almost useless.
    Reply
  • Twonky - Wednesday, March 13, 2013 - link

    For information about a year ago the following post on the Linkedin ARM Based Group gave a link to a M.Sc. thesis publishing figures on the performance/watt ratio for Cortex-A8 and Cortex-A9 based boards:
    www.linkedin.com/groups/Single-CortexA8-CortexA9-in-comparison-85447.S.84348310
    Reply
  • AncientWisdom - Tuesday, March 12, 2013 - link

    Very interesting read, thanks! Reply
  • staiaoman - Tuesday, March 12, 2013 - link

    Damn, Johan. As always- an incredible writeup. Interesting thought experiment to figure that an upper bound on damage to INTC server share might be found by simply looking at how much of the market is running applications like your web server here (where single-threaded performance isn't as important).

    Intel powering phones and ARM chips in servers...the end is nigh.
    Reply
  • JohanAnandtech - Thursday, March 14, 2013 - link

    Thanks Staiaoman :-). I'll leave the though experiment to you :-) Reply

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