DRAMSpec - A DRAM Current and Timing Generator

If you use DRAMSpec in your research, we would appreciate a citation to:

A High-Level DRAM Timing, Power and Area Exploration Tool, O. Naji, A. Hansson, C. Weis, M. Jung, N. Wehn., IEEE International Conference on Embedded Computer Systems Architectures Modeling and Simulation (SAMOS), July, 2015, Samos Island, Greece, DOI

BibTeX:

@INPROCEEDINGS{DRAMSpec,
author={O. Naji and C. Weis and M. Jung and N. Wehn and A. Hansson},
booktitle={2015 International Conference on Embedded Computer Systems: Architectures, Modeling, and Simulation (SAMOS)},
title={A high-level DRAM timing, power and area exploration tool},
year={2015},
pages={149-156},
keywords={DRAM chips;energy conservation;logic design;memory architecture;microprocessor chips;DDR3;DRAMSpec;energy saving;mobile devices;open source high-level DRAM bank modeling tool;processor designers;servers;Computational modeling;Computer architecture;Delays;Integrated circuit modeling;Performance evaluation;Random access memory},
doi={10.1109/SAMOS.2015.7363670},
month={July},}

For more information about our other tools please visit: http://www.uni-kl.de/3d-dram/tools/

LICENSE

Copyright (c) 2015-2017, University of Kaiserslautern All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Author: Omar Naji, Matthias Jung, Christian Weis, Kamal Haddad, Andre Lucas Chinazzo

Installing

DRAMSpec requires some libraries from boost. If you do not have it or the version you have is older than the 1.58, please follow the first four (4) steps from their getting started section. After updating your boost version, make sure to link it properly in the project file.

DRAMSpec is built as a Qt Creator project, therefore requiring the qmake tool. If you do not have Qt installed, you can find it here. The current version of DRAMSpec is properly built by QMake version 3.0 and Qt version 5.2.1 or newer. You can check your QMake and Qt version using the following command:

    qmake --version

Cloning from github (recursive to get submodules!)

    git clone --recursive <URL>

Building DRAMSpec

1. To be sure DRAMSpec repository was properly cloned, build and run the program in test mode either by using the script below or compiling and running the debug version of the program manually. If chosen to do manually, make sure you run the executable directly from within the directory build/debug!

    ./runTests.sh

2. After getting the "No errors detected" message, you are ready to build DRAMSpec itself. To do that, simply run the buildDRAMSpec.sh script:

    ./buildDRAMSpec.sh

The executable is now available under build/release/ by the name dramspec.

Running DRAMSpec

The program expect as parameters (at least) one technology and one achitecture description files. The flags -t and -p precede the technology and architecture description files, respectively.

The optional -term flag will include the IO termination currents for read and write operations of the DRAM.

For more detailed information on timings, it is possible to print out all internal timing variables using the flag -internaltimings.

    ./build/release/dramspec -t <path/to/technologyfilename> -p <path/to/parameterfilename> [-term] [-internaltimings]

Examples:

    ./build/release/dramspec -t technology_input/techddr3_5x.json -p architecture_input/parddr3.json

It is also possible to run multiple input files at once:

    ./build/release/dramspec -t <t1.json> <t2.json> -p <p1.json> <p2.json> [-term] [-internaltimings]

Note: the number of technology and architecture description files must be equal.

Input Data

DRAM Technology related inputs

Parameter	Description	Unit
TechnologyNode	Technology node (not used in any calculation).	um
Vdd	Main power supply voltage.	V
Vpp	Wordlines HIGH level voltage.	V
WireResistance	Wire resistance per length unit (Sheet resistance).	Ohm/mm
WireCapacitance	Wire capacitance per length unit (Sheet capacitance).	fF/mm
CellCapacitance	Total capacitance of a single cell.	fF
CellResistance	Total resistance of a single cell.	KOhm
CellWidth	Length in row direction of a single cell.	um
CellHeight	Length in column direction of a single cell.	um
BitlineCapacitancePerCell	Capacitance due to each cell connected to the local bitline.	aF
BitlineResistancePerCell	Resistance due to each cell connected to the local bitline.	Ohm
WordlineCapacitancePerCell	Capacitance due to each cell connected to the local wordline.	aF
WordlineResistancePerCell	Resistance due to each cell connected to the local wordline.	Ohm
PrimarySenseAmpHeight	Lenght in column direction of the primary sense amplifier.	um
LocalWordlineDriverWitdh	Lenght in row direction of the local wordline driver.	um
LocalWordlineDriverResistance	Output resistance of the local wordline driver.	Ohm
RowDecoderWidth	Length in row direction of the row address decoder.	um
GlobalWordlineDriverResistance	Output resistance of the global wordline driver.	Ohm
SecondarySenseAmpCurrent	Current sinked by the secondary sense amplifier.	uA
WriteDriverResistance	Output resistance of the write driver.	Ohm
ColumnDecoderHeight	Lenght in column direction of the column address decoder.	um
CSLDriverResistance	Output resistance of the column select line driver.	Ohm
CSLLoadCapacitance	Column select line capacitive load (LBL to GBL transistors gates).	fF
GlobalDataLineDriverResistance	Output resistance of the global dataline driver.	Ohm
DQDriverHeight	Length in column direction of the DQ driver.	um
DQtoTSVWireLength	Length of the wire from DQ main line to TSV connection.	um
DQDriverResistance	Output resistance of the DQ driver.	Ohm
IDD2NFreqSlope	Slope in relation to operating frequency of the precharge background current.	mA/MHz
IDD2NTempAlpha	Alpha coeff. (alpha * (exp(beta * (T - TRef)) - 1)) in relation to operating temperature of the precharge background current.	mA
IDD2NTempBeta	Beta coeff. (alpha * (exp(beta * (T - TRef)) - 1)) in relation to operating temperature of the precharge background current.	C^-1
IDD2NRefTemp	Ref. temperature (alpha * (exp(beta * (T - TRef)) - 1)) in relation to operating temperature of the precharge background current.	C
IDD2NOffset	Constant term of precharge background current. It is IDD2n at 0 MHz and TRef.	mA
OCDCurrentSlope	Slope of current sinked by the off-chip driver in relation to operating frequency.	uA/MHz
FullySharedResourcesCurrent	Current drawn by resources shared by all banks. For example, O/I interface, supply voltage generators and common control logic [5].	mA
SemiSharedResourcesCurrent	Current drawn by resources shared by some* banks. For example, O/I interface, supply voltage generators and common control logic [5].	mA
nBanksPerSemiSharedResource	*Number of banks that share each semi global resource.	mA
TSVHeight	Length in column direction of TSV area.	um
AdditionalTRLLatency	Added latency (tAL [2]) to tCAS resulting in tRL.	cc
DriverEnableDelay	Time interval between driving signal to active driver.	ns
InOutSSADelay	Signal delay from input to output of the secondary sense amplifier.	ns
CommandDecoderDelay	Clock wave pipeline delay for decode and fetch command in the same cycle it is registered.	ns
IODelay	I/O interface delay.	ns
SSAPrechargeDelay	Secondary sense amplifier precharge delay.	ns
tWRMargin	Security margin for Write Recovery.	ns
EqualizerDelay	Equalizer circuit enabling delay.	ns
VppPumpsEfficiency	(Optional) Efficiency of voltage pumps for Vpp, when existing.	-

DRAM Architecture related inputs

Parameter	Description	Unit
DRAMType	DRAM type. Currently only differenciates between DDR or SDR.	-
3D	Flag for 3D designs. ON means it is a 3D design.	-
DLL	Flag for the usage of Dealy-Locked Loop. ON means the DRAM uses DLL.	-
ExternalVPP	(Optional) Flag for the existance of external Vpp voltage source. YES/NO.	-
ChannelSize	Data storage capacity of a single channel.	Gbit
NumberOfBanksPerChannel	Total number of banks in a single channel.	dimensionless
NumberOfHorizontalBanksPerChannel	Number of banks in row direction. (Optional)	dimensionless
NumberOfVerticalBanksPerChannel	Number of banks in a column direction. (Optional)	dimensionless
CellsPerSubarrayRow	Number of cells in row direction in a subarray, including redundace.	dimensionless
RedundantCellsPerSubarrayRow	Number of redundant cells in row direction in a subarray.	dimensionless
CellsPerSubarrayColumn	Number of cells in column direction in a subarray, including redundance.	dimensionless
RedundantCellsPerSubarrayColumn	Number of redundant cells in column direction in a subarray.	dimensionless
Interface	Number of datalines of the IO bus. This number is the length of a single data word.	bit
Prefetch	Number of prefetched data words for a single read command (RD).	dimensionless
Frequency	Nominal Synchronous DRAM clock frequency.	MHz
CoreFrequency	DRAM Core clock frequency. Set to 0 (zero) for automatic calculation.	MHz
TilesPerBank	Number of tiles (subsections) of a single bank.	dimensionless
PageSize	Amount of data sensed after an bank activate command (ACT).	KByte
PageSpanningFactor	Percetange of page size sensed on a single bank tile.	dimensionless
SubarrayToPageFactor	Ratio between number of cells in a physical row and the page size.	dimensionless
BitlineArchitecture	Chosen architecture of bitlines. Can be either OPEN bitlines, or FOLDED bitlines.	-
RetentionTime	Minimum amout of time each and every cell must keep its information before being refreshed.	ms
tREFI(base)	Base average interval between two AREF commands (1X refresh mode, normal temperature). Please see [4] for reference.	us
RefreshMode	Base tREFI divider for effective tREFI [4]. Please use 1, 2, etc, for X1, X2, ect, refresh modes.	dimensionless
Temperature	Operating temperature of the device.	C

Output Data

Timings [2]

Abbreviation	Description	Unit
Frequency	Nominal Synchronous DRAM clock frequency.	MHz
Core Frequency	DRAM core clock frequency.	MHz
Max Core Frequency	Maximun DRAM core clock frequency.	MHz
	ESTIMATED ANALOG DELAYS
tRCD	Row to Column command Delay. The time interval between row access and data ready at sense amplifiers.	ns
tCL or tCAS	Column Access Strobe delay. The time interval between column access command and the start of data return by the DRAM device(s).	ns
tRAS	Row Access Strobe delay. The time interval between a row access command and data restoration in a DRAM array.	ns
tRP	Row Precharge delay. The time interval that it takes for a DRAM array to be precharged for another row access.	ns
tRC	Row Cycle delay. The time interval between accesses to different rows in a bank. tRC = tRAS + tRP.	ns
tRL	Read Latency delay. tRL = tCL + tAL, where tAL is the Added Latency to column accesses.	ns
tRTP	Read to Precharge delay. The time interval between a read and a precharge command.	ns
tCCD	Column-to-Column Delay. The minimum intra-device column-to-column command timing, determined by internal prefetch length.	ns
tWR	Write Recovery delay. The minimum time interval between the end of write data burst and the start of a precharge command.	ns
tRFC	Refresh Cycle delay. The time interval between Refresh and Activation commands.	ns
tREFI	Refresh Interval. Average time interval in between Refresh commands.	ns
	ESTIMATED LATENCIES (in minimum number of clock cycles)
tRCD	Row to Column command Delay latency. The time interval between row access and data ready at sense amplifiers.	cc
tCL or tCAS	Column Access Strobe latency. The time interval between column access command and the start of data return by the DRAM device(s).	cc
Core tCL or tCAS	Column Access Strobe latency. The time interval between column access command and the start of data return by the DRAM device(s). Given in minimum number of clock cycles of the DRAM core.	cc
tRAS	Row Access Strobe latency. The time interval between a row access command and data restoration in a DRAM array.	cc
tRP	Row Precharge latency. The time interval that it takes for a DRAM array to be precharged for another row access.	cc
tRC	Row Cycle latency. The time interval between accesses to different rows in a bank. tRC = tRAS + tRP.	cc
tRL	Read Latency latency. tRL = tCL + tAL, where tAL is the Added Latency to column accesses.	cc
Core tRL	Read Latency latency. tRL = tCL + tAL, where tAL is the Added Latency to column accesses. Given in minimum number of clock cycles of the DRAM core.	cc
tRTP	Read to Precharge latency. The time interval between a read and a precharge command.	cc
tCCD	Column-to-Column Delay latency. The minimum intra-device column-to-column command timing, determined by internal prefetch length.	cc
Core tCCD	Column-to-Column Delay latency. The minimum intra-device column-to-column command timing, determined by internal prefetch length. Given in minimum number of clock cycles of the DRAM core.	cc
tWR	Write Recovery latency. The minimum time interval between the end of write data burst and the start of a precharge command.	cc
tRFC	Refresh Cycle latency. The time interval between Refresh and Activation commands.	cc
tREFI	Refresh Interval latency. Average time interval in between Refresh commands.	cc

Currents [3, 4, 5]

Abbreviation	Description	Unit
IDD0	Operating One Bank Active-Precharge Current.	mA
IDD1	Operating One Bank Active-Read-Precharge Current.	mA
IDD2N	Precharge Standby Current	mA
IDD3N	Active Standby Current	mA
Rho [5]	Ratio of (IDD3N - IDD2N) which is independent on number of active banks	-
IDD4R	Operating Burst Read Current	mA
IDD4W	Operating Burst Write Current	mA
IDD5B	Burst Refresh Current	mA

Physical sizings

Parameter	Description	Unit
Subarray height	Height (column direction) of one subarray including sense amplifier.	um
Subarray width	Width (row direction) of one subarray including local wordline driver.	um
Tile height	Height (column direction) of one tile (bank subsection) including column address decoder.	um
Tile width	Width (row direction) of one tile (bank subsection) including row address decoder.	um
Bank height	Height (column direction) of one bank including DQ driver.	um
Bank width	Width (row direction) of one bank.	um
Channel height	Height (column direction) of one channel including TSV if 3D design.	um
Channel width	Width (row direction) of one channel.	um
Channel area	Area of one channel.	(mm)^2

Reference

[1] A High-Level DRAM Timing, Power and Area Exploration Tool, O. Naji, A. Hansson, C. Weis, M. Jung, N. Wehn, IEEE International Conference on Embedded Computer Systems Architectures Modeling and Simulation (SAMOS), July, 2015, Samos Island, Greece, DOI

[2] Memory Systems: Cache, DRAM, Disk, B. Jacob, S. Ng and D. Wang, Morgan Kaufmann, 2007

[3] DDR3 SDRAM standard (revision F), JEDEC, July 2012.

[4] DDR4 SDRAM standard (revision B), JEDEC, June 2017.

[5] A New Bank Sensitive DRAMPower Model for Efficient Design Space Exploration, M. Jung, D. Mathew, É. Zulian, C. Weis, N. Wehn, IEEE International Workshop on Power and Timing Modeling, Optimization and Simulation (PATMOS), Sept., 2016, Bremen, Germany.