NVRAMOS ‘11 November 8, 2011, Jeju SSD Characterization: From Energy Consumption's Perspective Youjip Won Hanyang University
Outline Outline Motivation p Related Works p SSD Organization and Energy Consumption p Channels, Ways and Clusters p Trivia in Measurement Methodology p Case Study p Power Budget p Conclusion p Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 2/68
Motivation 3/68
Motivation Motivation Understanding of Internal Mechanism of Storage Device is very important! p Hard disk w Sector layout: cylinder serpentine vs. surface serpentine vs. hybrid serpentine w Number of zones w Degree of track skew w Disk scheduling algorithm Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 4/68
Characterizing HDD: Sector Layout Characterizing HDD: Sector Layout Jongmin Gim et al, ACM ToS 6, 2 (July 2010) p Surface serpentine Traditional Spindle Spindle Spindle Spindle Cylinder serpentine Zone rewind Spindle Spindle Spindle Spindle Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 5/68
Characterizing Storage Devices Characterizing Storage Devices HDD Characterization is via measuring Seek time and Rotational Latency. HDD Characterization is via measuring Seek time and Rotational Latency. Characterizing SSD… what do we use?... Characterizing SSD… what do we use?... Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 6/68
Motivation Motivation How do we figure out the internals of SSD? How do we figure out the internals of SSD? p What is available w the number of channels w the number of chips/packages per channels p What is not available? w Sector placement , Garbage collection algorithm Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 7/68
Operations on NAND Flash Cell Operations on NAND Flash Cell program erase 18~35V Control Gate Control Gate Oxide Layer Floating Gate - - - Floating Gate - - - Source Drain Source Drain Substrate Substrate Programed: 1 -> 0 Erased : 0 -> 1 Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 8/68
Operations on NAND Flash Cell Operations on NAND Flash Cell Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 9/68
SSD Characterization SSD Characterization We will use “Energy Consumption” Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 10/68
Related Works 11/68
Related Works Related Works Dongkun Shin et al, NVRAMOS 2010 Spring p Identifying the relationship between workload characteristics and Identifying the relationship between workload characteristics and aggregate power consumption for each workload aggregate power consumption for each workload Applied mixed workloads(random, sequential, etc) to SSDs Applied mixed workloads(random, sequential, etc) to SSDs with different request sizes and varied the file systems with different request sizes and varied the file systems Measured the Power Consumption(measured voltage change) Measured the Power Consumption(measured voltage change) Laura M. Grupp et al, MICRO 2009 p Power Consumption of Flash Power Consumption of Flash Read Read Memory Basic Operations Memory Basic Operations Program Program Examine the average Erase Erase power consumption(W) and energy(J) Custom Board Basic Operation + Flash Memory Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 12/68
Related Works Related Works Euiseong Seo et al, HotPower’08 p Analyzed the power consumption patterns of the SSDs Analyzed the power consumption patterns of the SSDs different hardware configurations to the various atomic operations and the different hardware configurations to the various atomic operations and the combination of file systems and workloads. combination of file systems and workloads. Vidyabhushan Mohan et al, Date ’10 p CACTI 5.3 developed a detailed power model developed a detailed power model for the NAND flash chip itself with CACTI 5.3 for the NAND flash chip itself with CACTI 5.3 Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 13/68
SSD Organization and Energy Consumption 14/68
Power Consumption of Storage Devices: System Boot Power Consumption of Storage Devices: System Boot Active current of HDD stand-by current s SSDs have various stand-by currents Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 15/68
SSD Organization SSD Organization DRAM DRAM Controller Controller Bus Host Host … … … … I/O I/O Physical Physical Interface Interface … … … … Host Interface … … … … … … … … NAND Flash Memory Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 16/68
Characteristics of SSD Behavior Characteristics of SSD Behavior =Page Write =Write Complete … … … … … … … … … … … … … … … … Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 17/68
IO Size vs. Energy Consumption IO Size vs. Energy Consumption Intel X25M … … … … … … … … … … … … … … … … … … … … Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 18/68
Power consumption vs. Channels, Ways, and Clusters 19/68
Read vs. Write Read vs. Write =Page Operation =Operation Complete Read Read Write Write … … … … … … … … C R D C D P Current(mA) Current(mA) time time Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 20/68
Writing 4 pages: 1 Channel X 1 Way Writing 4 pages: 1 Channel X 1 Way =Page Write =Write Complete … … … … C D P Current(mA) time Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 21/68
Way switch vs. Channel switch Delay Way switch vs. Channel switch Delay =Page Write =Write Complete Way Switch Way Switch Channel Switch Channel Switch … … … … … … … … C D P C D P Current(mA) Current(mA) Way Switch Way Switch Channel Switch Channel Switch time time Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 22/68
Writing 4 pages: 1 Channel X 2 Way Writing 4 pages: 1 Channel X 2 Way =Page Write =Write Complete … … … … C D P Current(mA) time Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 23/68
Writing 4 pages: 2 Channel X 1 Way Writing 4 pages: 2 Channel X 1 Way =Page Write =Write Complete … … … … C D P Current(mA) time Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 24/68
Writing 4 pages: 2 Channel X 2 Way Writing 4 pages: 2 Channel X 2 Way =Page Write =Write Complete … … … … C D P Current(mA) Way Way Switch Switch Channel Switch Channel Switch time Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 25/68
Cluster Cluster p Cluster : Write Unit of SSD =Page Write 4KB Write 4KB Write 8KB Write 8KB Write … … … … = … … … … Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 26/68
Trivia in Measurement Methodology 27/68
Trivia of Measurement Methodology Trivia of Measurement Methodology Sampling interval should be smaller than Read/Program Latency Sampling interval should be smaller than Read/Program Latency p Smoothing the data to filter out measurement noise. Smoothing Smoothing Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 28/68
Trivia of Measurement Methodology Trivia of Measurement Methodology p Deactivate DRAM cache w SATA command 82h ¢ Samsung MXP and Intel X-25M SSDs w Trigger DRAM flush ¢ OCZ Vertex and Hanamicron Forte+ Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 29/68
Case Studies 30/68
Measurement Measurement Model Vendor Size Channels DRAM Size Package Type X25M Intel 80GB 10 16MB 20 MLC MXP SAMSUNG 128GB 8 128MB 16 MLC Vertex OCZ 60GB 8 64MB 16 MLC Forte+ Hanamicron 32GB 8 32MB 8 MLC Oscilloscope (TDS3032) p High resolution current probe(TCP202) p Current probe to power line(Vdd) of the SSD p Sampling interval(10samples MA): 10usec p Each request measured 10 times p Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 31/68
Case Study : Intel X25M Case Study : Intel X25M Intel X25M Capacity 80GB No. of Channels 10 Packages/Channel 2 Package 4 GB … … … … … … … … … … … … … … … … … … … … NAND (4GB) Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 32/68
Case Study : Intel X25M Write Case Study : Intel X25M Write p IO Size: 4KB to 80KB Channel switch = 30 μsec Channel switch = 30 μsec Increase Increase NAND programming: 17 mA NAND programming: 17 mA 20 steps 20 steps 600 μ sec 600 μ sec Simple Round Robin Simple Round Robin 17mA 17mA 100mA 100mA Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 33/68
Case Study : Intel X25M Write Case Study : Intel X25M Write p 4KB to 80KB Sequential Write = Page Write Channel Switch =30 μsec Channel Switch =30 μsec 11 10 1213141516171819 0 1 2 3 4 5 6 7 8 9 MUX MUX … … … … … … … … … … … … … … … … … … … … Youjip Won Hanyang University NVRAMOS’11, Jeju, Korea 34/68
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