I'm setting up a Dell Poweredge 750 1U server. A friend is loaning me space in his rack and since his rack usage is limited by power I'd like to be as thrifty as possible. I hooked my kill-a-watt meter up and ran the machine for a couple of days and it uses 88 watts (3.90KWH/44.01H). Then I kldloaded cpufreq and enabled powerd and it still uses 88 watts (8.35KWH/93.47H). That surprised me a bit, and seems to suggest that it's spending most of its energy spinning fans or something. Is anyone familiar with the poweredge 750 and freebsd-stable? I can't find anything in the bios that suggests fans control, although I guess it's possible that they're running efficiently by default and I just haven't caused them to *really* run. Any other suggestions to help economize? Thanks, g.
On Wednesday, 10. January 2007 19:34, George Hartzell wrote:> I'm setting up a Dell Poweredge 750 1U server. A friend is loaning me > space in his rack and since his rack usage is limited by power I'd > like to be as thrifty as possible. > > Any other suggestions to help economize? >edit /etc/rc.conf: powerd_enable="YES" powerd_flags="-a adaptive -b adaptive"
On Wed, 2007-Jan-10 09:34:21 -0800, George Hartzell wrote:>I hooked my kill-a-watt meter up and ran the machine for a couple of >days and it uses 88 watts (3.90KWH/44.01H).What was it doing for those couple of days? If it was just sitting idle then I would expect the power consumption to be fairly close to what you get with powerd. If you want to see peak power consumption, try running a buildworld, something very FP intensive and something that is thrashing the disk(s) (lots of seeks and writes), all in parallel.>Then I kldloaded cpufreq and enabled powerd and it still uses 88 watts >(8.35KWH/93.47H).I presume you confirmed that cpufreq/powerd was actually functioning (ie the CPU frequency was being changed).>That surprised me a bit, and seems to suggest that it's spending most >of its energy spinning fans or something.PSU overheads, fans, northbridge, video, RAM, disk, ... it all adds up. I can't specifically help with the Dell. -- Peter Jeremy -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 187 bytes Desc: not available Url : http://lists.freebsd.org/pipermail/freebsd-stable/attachments/20070110/9dfb522b/attachment.pgp
On Jan 10, 2007, at 9:34 AM, George Hartzell wrote:> I'm setting up a Dell Poweredge 750 1U server. A friend is loaning me > space in his rack and since his rack usage is limited by power I'd > like to be as thrifty as possible. > > I hooked my kill-a-watt meter up and ran the machine for a couple of > days and it uses 88 watts (3.90KWH/44.01H). > > Then I kldloaded cpufreq and enabled powerd and it still uses 88 watts > (8.35KWH/93.47H). > > That surprised me a bit, and seems to suggest that it's spending most > of its energy spinning fans or something.There isn't going to be nearly as much power savings running powerd with a desktop or rackmount equipment than with a laptop-- the latter are designed with a low-power mode of operation as a priority due to limited battery life. Also, I think that powerd also doesn't help that much compared with the "HLT in the idle task" approach that has been used previously, but YMMV. Also note that most power supplies are rated for around 80 - 90% efficiency, which means that a 400W power supply under full design load would be be drawing 440 to 480 W. However, even under zero load, they'll still eat a few watts. Unless you replace the machine with something like a VIA EPIA or a Soekris 45xx/48xx using very low power components, you're going to have a tough time getting your power draw down much lower than the ~90 W. -- -Chuck
George Hartzell wrote:
> I'm setting up a Dell Poweredge 750 1U server. A friend is loaning me
> space in his rack and since his rack usage is limited by power I'd
> like to be as thrifty as possible.
>
> I hooked my kill-a-watt meter up and ran the machine for a couple of
> days and it uses 88 watts (3.90KWH/44.01H).
>
> Then I kldloaded cpufreq and enabled powerd and it still uses 88 watts
> (8.35KWH/93.47H).
Did you verify that powerd actually reduced the CPU
frequency? What's the output from "sysctl dev.cpu.0"?
It might be enlightening to watch the following shell
loop for a while:
while :; do sysctl dev.cpu.0.freq; sleep 1; done
By the way, do you have an SMP system, or are you running
a kernel without SMP? "sysctl machdep.cpu_idle_hlt"?
Best regards
Oliver
--
Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing
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