[Beowulf] [EXTERNAL] Re: Is Crowd Computing the Next Big Thing?

Lux, Jim (US 337K) james.p.lux at jpl.nasa.gov
Thu Nov 28 11:58:30 PST 2019

Don't forget background loads like the cooling fan, losses in the power supply, etc.  Most power supplies (even switchers, unless specifically designed for this) have lower efficiency at lower loads.  

´╗┐On 11/28/19, 12:39 AM, "Beowulf on behalf of Janne Blomqvist" <beowulf-bounces at beowulf.org on behalf of janne.blomqvist at aalto.fi> wrote:

    On 27/11/2019 22.56, Lux, Jim (US 337K) via Beowulf wrote:
    > With respect to "free cycles" in desktop computers - back in the day, 10-15 years ago, a bunch of folks made measurements on cluster nodes of one sort or another.  As I recall, there *is* a power consumption change between full load and not, but there's a significant "background load" that is more than 50% of the total power consumption.
    With current hardware, there is a significant difference (at least,
    assuming the "ipmi-dcmi --get-system-power-statistics" output is
    correct). On our skylake nodes ("standard 2-socket CPU nodes") idle
    power is about 50W, when running flat out about 400W.
    Somewhat older hardware is less good at saving power when idle, Westmere
    nodes consume about 100W idling. IIRC our old Istanbul Opterons (which
    we have already thrown away, so can't double-check) consumed about 170W
    when idle.
    Janne Blomqvist
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