Update on Overleaf.
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@@ -277,9 +277,9 @@ Still, the tool has two drawbacks: it only models core power, but no interface p
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Another simulation tools similar to DRAMPower is VAMPIRE~\cite{ghoyag_18}.
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Another simulation tools similar to DRAMPower is VAMPIRE~\cite{ghoyag_18}.
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This tool puts its focus on the power variations between different DRAM modules, within one DRAM module depending on the access location, and the data value dependency.
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This tool puts its focus on the power variations between different DRAM modules, within one DRAM module depending on the access location, and the data value dependency.
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VAMPIRE is calibrated with measurements of real DRAM modules and provides very accurate results.
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VAMPIRE is calibrated with measurements of real DRAM modules and provides very accurate results.
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However, this presupposes that real measurements are available for the devices to be used, which is not usually the case in the early stages of design.
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However, this presupposes that real measurements are available for the devices to be used, which is not usually the case in the early stages of design. VAMPIRE also supports DDR3 only.
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VAMPIRE also supports DDR3 only.
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\todo{analytical core power model Vogelsang, highly proprietary IP}
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There exists an analytical DRAM core-power model by Vogelsang~\cite{vog_10}. This model reflects a DDR memory but is also used to extrapolate future memory power consumption behavior.
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When it comes to DRAM interface power modeling, the most popular software is CACTI-IO~\cite{joukah_12,joukah_15}.
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When it comes to DRAM interface power modeling, the most popular software is CACTI-IO~\cite{joukah_12,joukah_15}.
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CACTI-IO does not rely on data sheet currents, but it uses an equivalent circuit diagram of the DRAM subsystem's real interface architecture as this architecture is not fixed for a specific device.
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CACTI-IO does not rely on data sheet currents, but it uses an equivalent circuit diagram of the DRAM subsystem's real interface architecture as this architecture is not fixed for a specific device.
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The power consumption is then calculated using a simplified network analysis.
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The power consumption is then calculated using a simplified network analysis.
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@@ -525,21 +525,29 @@ Thus, when a burst refresh current is provided, the energy for a single refresh
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E_{REF} = V_{DD} \cdot \left(I_{DD5B} - I_{\circled{N}}\right) \cdot t_{RFC}
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E_{REF} = V_{DD} \cdot \left(I_{DD5B} - I_{\circled{N}}\right) \cdot t_{RFC}
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\end{equation}
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\end{equation}
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where $N$ is the number of refreshed banks.
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where $N$ is the number of refreshed banks.
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As the equation shows, banks with a refresh in progress are considered active, which the most accurate way of modeling because internally the refresh is performed by successively activating multiple rows within each target bank.
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In the cases where only an average refresh current $I_{DD5A}$ is provided, an approximated value for $I_{DD5B}$ can be determined.
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During refresh, the targeted banks are considered active because
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Figure demonstrates the relation between both refresh currents graphically, where the dashed boxes represent the energy that is consumed.
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The voltage is neglected because it is a constant.
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As explained in Section~\ref{subsec:current_measurement}, JEDEC
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\begin{figure}
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\begin{figure}
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\centering
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\centering
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\resizebox{\linewidth}{!}{%
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\resizebox{\linewidth}{!}{%
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\input{img/refresh_currents}
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\input{img/refresh_currents}
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}
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}
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\caption{Refresh Currents}
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\caption{Relation between Refresh Currents}
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\label{fig:refresh_currents}
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\label{fig:refresh_currents}
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\end{figure}
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\end{figure}
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This means that refreshed banks have to be considered as active in the background power calculation.
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During refresh, the targeted banks are considered active because
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As explained in Section~\ref{subsec:current_measurement}, JEDEC
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\begin{equation}
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\begin{equation}
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I_{DD5B} = I_{DD2N} + \left(I_{DD5A} - I_{DD2N}\right) \cdot \frac{t_{REFI}}{t_{RFC}}
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I_{DD5B} = I_{DD2N} + \left(I_{DD5A} - I_{DD2N}\right) \cdot \frac{t_{REFI}}{t_{RFC}}
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\end{equation}
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\end{equation}
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@@ -8,6 +8,7 @@
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\newcommand{\ya}{1}
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\newcommand{\ya}{1}
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\newcommand{\yb}{2.6}
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\newcommand{\yb}{2.6}
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\newcommand{\yc}{6}
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\newcommand{\yc}{6}
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\newcommand{\yd}{7}
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\pgfdeclarelayer{background}
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\pgfdeclarelayer{background}
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\pgfsetlayers{background, main}
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\pgfsetlayers{background, main}
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@@ -20,7 +21,7 @@
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ymin=0, ymax=7,
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ymin=0, ymax=7,
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xtick=\empty,
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xtick=\empty,
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ytick=\empty,
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ytick=\empty,
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extra y ticks={\ya, \yb, \yc},
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extra y ticks={\ya, \yb, \yc, \yd},
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extra y tick labels={$I_{DD2N}$, $I_{DD5A}$, $I_{DD5B}$},
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extra y tick labels={$I_{DD2N}$, $I_{DD5A}$, $I_{DD5B}$},
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axis x line=middle,
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axis x line=middle,
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axis y line=middle,
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axis y line=middle,
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