1 The Problem of Power Consumption in Servers L. Minas and B. Ellison Intel-Lab In Dr. Dobb’s Journal, May 2009 Prepared and presented by Yan Cai Fall 2009 Green Computing

Motivation Server energy consumption has increased from 50w to 250w since 2000 Energy cost will exceed the server cost if this trend does not change 2 Source: IDC, Scaramella 2006

Outline Motivation Where heat comes from How cooling is achieved How power is consumed Conclusions 3

Where heat comes from Server form factor Server power consumption is affected by server form factor, including  the individual configuration,  the heat and thermal environment  the workload being processed  … 4 Server form factor Pedestal servers 2U rack servers 1U rack servers Blade servers 1U Pedestal 2U Blade

Where heat comes from The amount of heat, (Q), generated by an integrated circuit is a function of  The efficiency of the components' design (e)  The technology used in its manufacturing process (t)  The frequency and voltage at which it operates (f,v) Over-clocking also generates a great amount of heat 5

Outline Motivation Where heat comes from How cooling is achieved How power is consumed Conclusions 6

How cooling is achieved Two common methods  Heat sinks  Fans 7 Natural convection heat sink (Source: Wikipedia, 2008)

Outline Motivation Where heat comes from How cooling is achieved How power is consumed Conclusions 8

How power is consumed ServersCost# of Processors Volume$25,0001 ~ 2 Mid-range$25,000 ~ $499,9992 ~ 4 High-end≥ $500,000≥ 8 9 Estimated Average Power Use (W) per Server, by Server Class, 2000 to 2006 (Source: Koomey J 2007b Estimating Total Power Consumption by Servers in the US and the World. Oakland, CA: Analytics Press) Estimated Average Power Use (W) per Server Google container Data Center

Total power consumption Power consumption of a Quadcore Intel Xeon server 10 Server Power Consumption (Source: Intel Labs, 2008)

Total power consumption (cont’d) Power consumption of components 11 ComponentsPower consumption Multi-core CPU45 ~ 200 w DIMM5 ~ 21 w Power supply efficiency lossSimilar with memory p.s. 2 PCI Slots50 w 2 ~ 4 Hard drives24 ~ 48 w

Total power consumption (cont’d) Total power consumption Estimation of power consumption 12 CPU Utilization and Power Consumption (Source: Blackburn 2008)

Memory power consumption The memory demand is growing in the future, because  More processors on chip,  Increasing use of virtualization,  More memory intensive search applications (Google and Facebook) The memory power consumption is growing in the future  The more the memories, the larger the power consumption  The faster the memories, the larger the power consumption 13

Memory power consumption (cont’d) Memory Power Comparison 14 RDIMM Memory Power Comparison (Source: Intel Platform Memory Operation, 2007)

Memory power consumption (cont’d) Power consumption by vendors and configurations 15 RDIMM Power Consumption by Vendor and Configuration (Sources: Publicly-available datasheets from each vendor, 2008)

Memory power consumption (cont’d) 64GB system power consumption 16 Future DIMM Power Consumption by Frequency, Configuration, and Capacity (Source: Intel Platform Memory Operation, 2008)

Memory power consumption (cont’d) How to reduce memory energy consumption  By doing thermal analysis, embedding thermal sensors and throttling 17 1U Server Architecture (Source: Intel Labs, 2006)

Memory power consumption (cont’d) Memory throttling mechanisms  Closed loop thermal throttling (CLTT) Closed loop, rely on thermal sensors  Open loop throughput throttling (OLTT) Open loop, work based on bandwidth count Memory throttling degrades performance 18

Power supply efficiency loss Power supply efficiency vs. utilization level 19 Server Power Supply Efficiency Test Report (Source: Lawrence Berkeley National Laboratory, 2004)

Storage power consumption Average hard disk power consumption for average operations Average hard disk power consumption for IO intensive operations 20

Conclusions High-end servers consume more power, but might be less efficient in terms of power consumption At present, CPU still consumes the most power, compared to other components In the future, memory can consume more power than CPU Considering a significant amount of power loss, the efficiency of power supplies is also very important The power consumption by hard drives is closely related to the workload the server is processing 21