[HARDWARE] Cost of crunching (was: Mac Questions)

John L. Bass jbass at dmsd.com
Mon Mar 18 00:43:57 EST 2002


Hi Thord,

Great numbers, let me fill in some additional data to help make sense of
some of it.

	In WIN95 there is no significant difference if the machine is 
	idle or crunching.

This depends greatly on BIOS PM (Power Management) settings, in WIN95
the power management drivers are not installed unless the BIOS has PM
enabled at install time - they can be installed manually later with
some effort. Most of the BIOS settings only take effect after a certain
(configurable) time period, and the degree of power savings is highly
variable (configurable). So I suspect that if you configure the BIOS
PM settings, re-install Win-95, that you will find that the power
consumption drops noticably when WIN95 is idle too, and will drop
into Standby/Suspend modes for considerably lower power usage as well.

A typical slim desktop PC (highly integrated, minimal configuration)
uses about 65W active, 35W Doze/Idle, and 5W in Suspend mode. Monitor
power is additional. Machines with high performance graphics cards,
lots of fast memory, multiple HDD's and other devices, use considerably
more power.

Most home PC's have less than 3 hrs/day of contact in household where
students and wage earners are out of the house 10-12hrs of each day.

Most desktop office PC's have an less than 5 hrs/day of contact, due to
meetings, phone, non-computer tasks at desk (like reading paper materials).
Many non-contact periods are greater than 5 minutes.

Most office servers have less than 10 hrs/day of contact, with most
activity concentrated in less than 5 hrs/day. Many servers can be
configured to wake on LAN activity with an external lan monitor
to trigger the wakeup packets and still provide acceptable request
latency on wakeup.

With properly configured STANDBY/SUSPEND values, a typical office will
save 85% of their computer power consumption without ever powering down
their machines. This is based on 25 hours of usage per week. For one
medical office client with 150 PC, properly configuring all the PC's PM
settings in their 4 office locations, cut their power usage over
11,000 KWH's/month for a savings of over $1,500/mo. It also cut the
after hours fire alarm events from 5/yr to none, caused by monitor and
power supply failure fires setting off smoke alarms. This saved another
$6,000/yr in emergency response charges for the false alarms charged by
the building managers. This was prior to last years high energy costs
in Calif - without these savings, the office's costs would have been
significantly larger.

The DOZE/IDLE BIOS settings control not only the number of minutes before
activated, but on many boards the degree of savings. In this mode the
processor duty cycle or clock rate is reduced - sometimes by as much as
95% - in many systems this will cut total power usage between 25-80% with
around 25-35% being the normal expected.

STANDBY mode is a little more agressive, where the monitor and HDD are
powered down too ... this saves the 15-25W of hard drive power, and
50-90W of monitor power, plus cutting the system power back.

SUSPEND mode shuts almost everything down, but leaves the system on life
support to recognize PM interrupts from TOD clock, and special I/O cards
(modems, NIC's, etc) which can generate a PM interrupt in the SUSPEND state.
A machine in SUSPEND mode is nearly OFF, and typically draws under 6W, with
under 1W being the current US "Green" requirement to "slay energy Vampires".
Most desktops and servers should be configured to drop into this mode with
5-30 minutes of idle time. Depending on OS, recovery time is typically
between 5-30 seconds once woken up. This is frequently faster than booting
from power off, and doesn't require a login and restarting of appliations.

There is a June 2001 federal mandate for all US offices to implement this
1W "Green" mandate as a leadership role for businesses in the US (and world).
SETI, Dnet, and similar programs completely negate this energy conservation
initiative which is trying to cut the uneccessary use of an estimated
52 Billion KWH/yr for devices like this in the US ... and over 200B KWH/yr
globally since the power plants involved contribute to both global warming
and unnecessary non-renewable energy usage.

Linux PM support is getting pretty good (see apmd), and has significant
power savings, using the BIOS to provide the machine specific support.
I suspect the better than 50% savings on the 2xCeleron numbers below
are due to PM kicking into DOZE/IDLE mode with apmd and BIOS PM enabled.
If SUSPEND was configured on the same machine, you should have seen the
power drop to less than 5W ... and if the hardware was properly configured,
the machine would resume from SUSPEND as needed. With PM and apmd, the machine
would cost typically $1.30/mo to operate with DOZE/SUSPEND enabled, and about
$8.40/mo running SETI/Dnet (not including monitor power) - a 650% power
consumption increase. Factoring in usage of machines that would otherwise
be scrapped or out of service, one can make an argument that these are
not spare cycles, but unnecessarly increasing power consumptions by an
order of magnitude for the machines used by the SETI/Dnet communities
as compared to responsible Green BIOS configuration usage.

Most machines built in the last 10 years are Green BIOS APM compliant.
It would be worth checking the BIOS settings on the machines below, and
enabling PM with reasonable timeout values, installing apmd on linux
for those machines and configuring ... and re-running the tests both
in IDLE, STANDBY (IDLE+HDD down) and after forcing into SUSPEND mode.

It's easy to blame the series of US involvement in middle east wars
because of excessive energy consumption, blame everyone else for
global warming, point a lot of fingers regaring everyone elses actions.
It's harder to accept that we each fail to contribute to global energy
conservation, by simply refusing to act responsibly, refusing to promote
conservation over consumption, by refusing to act positively as role
models.

John Bass


	(It even takes LESS power with certain programs)
	Also the RC5, DES, OGR CSC takes different power. (on some machines DES
	takes more than RC5 on onther less)

	Assuming:
	All machines run on Linux.
	The cost for 10 KWh is 1 USD.
	The machines are on anyway, only extra power is from crunching vs idling.
	Total # of keys to check = 2^64.
	USD = Delta/10000/3600/Perf * 2^64  (Perf is in keys/sec)

	                    Power in W                 Performance  M-USD to
	System              Running RC5  idle   Delta   Mkeys/s     complete***

	486-DX4-OD 100 MHz     112.8     102.8   10      0.093       55.1  (621)
	Alpha 21064 100 MHz**   88.8      85      3.8    0.086       22.6  (528)
	Pentium-MMX 200 MHz     41        32      9      0.428       10.8   (49)
	AMD-K6 233 MHz		72.5      35     37.5    0.400       48.0   (93)
	AMD-K62 500 MHz         84        57     27      0.864       22.2   (69)
	2xCeleron 450 MHz      116.7      55     61.7    2.544       12.4   (23)
	Athlon TB 1100 MHz     115        98.3   16.7    3.388        2.5   (17)

	*   Celeron 300A overclocked to 450 MHz.

	**  Running OGR actually takes less power than idling.

	*** Number in () is if machine is on because of crunching.
	    This number is not really representative for the CPU since all
	    machines have different pheripherals, like sound card, number
	    of HD:s CD-ROM/CD RW, memory etc...


	/Thord.


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