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w15 slices around 2/3 ~ 3/4 done?

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Zhengyi Chen 2024-01-30 20:00:58 +00:00
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tex/misc/w15_slides.tex
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@ -204,24 +204,174 @@
\end{frame}
\begin{frame}
\frametitle{Consistency Model}
\frametitle{Protocol Excerpt: Write-Invalidate}
\begin{figure}
\centering
\includegraphics[width=\linewidth]{
w12_slides_resources/Fig-RwlockProtocol 2023-12-06 19_05_06.pdf
}
\end{figure}
The \textit{T}-state indicates a transitionary state for some shared page.
\end{frame}
\begin{frame}
\frametitle{Coherence Protocol}
\frametitle{Consistency Model: TSO}
\begin{itemize}
\item {
Total Store Ordering allows Reads to bypass Stores.
}
\item {
Assuming correct use of node-local synchronization on all nodes,
applying TSO in a home-based DSM allows for:
\begin{itemize}
\item {
When another node tries to read T-page from access-control
node: W$\rightarrow$R violation.
}
\item {
When another node tries to read S-page from data-provider
nodes: W$\rightarrow$R violation (if e.g., the invalidation
message from access-control node was received afterwards).
}
\item {
Data-provider and access-control nodes work on one request
at a time: no R$\rightarrow$W violation.
}
\item {
Write-accesses serialized at access-control node: no
W$\rightarrow$W violation.
}
\end{itemize}
}
\end{itemize}
\end{frame}
\begin{frame}
\frametitle{Stateful Nodes}
\frametitle{Consistency Model: Strengthen to Sequential}
\begin{itemize}
\item {
By corollary, can reverse the previous page's statements to
strengthen to sequential consistency:
\begin{itemize}
\item {
Disallow T-pages from being serviced until new page content
is installed: lengthens critical section.
}
\item {
Abolish data-provider nodes: access-control nodes become
bottleneck.
}
\end{itemize}
}
\end{itemize}
\end{frame}
\begin{frame}
\frametitle{Coherence Protocol: Possible Features}
\begin{itemize}
\item {
Multi-data-provider Protocol: Instead of having one data-provider,
have multiple data-provider nodes that are automatically write-back
to prevent network bottleneck.
\begin{itemize}
\item Data provider nodes may be dynamically assigned.
\item Extra metadata can limit scalability.
\end{itemize}
}
\item {
Auto-share: likewise, write-back pages to non-data-provider nodes to
take advantage of 1-sided communications.
}
\item {
Request aggregation: aggregate RDMA transfers for optimal transfer
performance.
\begin{itemize}
\item Need to be coherent with program sequence!
\item Enables write-request merging.
\end{itemize}
}
\end{itemize}
\end{frame}
\begin{frame}
\frametitle{Stateful Nodes \& Transitions (Provisional)}
\begin{itemize}
\item {
Nodes (e.g., within the cluster) become tightly bound with the
properties of each shared page(s).
}
\end{itemize}
\begin{figure}
\centering
\includegraphics[width=\linewidth]{
w15_resources/截屏 2024-01-30 19.15.45 2024-01-30 19_16_19.png
}
\end{figure}
\end{frame}
\begin{frame}
\frametitle{Stateful Nodes \& Transitions (Provisional) (Cont.)}
\begin{itemize}
\item {
MN (Manager Nodes): Provide access-control and (fallback)
data-provision.
}
\item {
HN (Home Nodes): Provide data-provision. Can be write-back or
write-invalidate.
}
\item {
SN (Sharer Nodes): Share data within a reader-only ``epoch''. Can be
write-back or write-invalidate.
}
\item {
NSN (Non-sharer Nodes): Nodes in network without sharing the
particular page(s).
}
\item {
CN (Commit Node): Node that acquired the single-writer access to the
shared page.
}
\item {
Message variants are not finalized:
\begin{itemize}
\item {
Goal: Composable message chains that allow for
``piggy-backing'' of multiple procedures.
}
\end{itemize}
}
\end{itemize}
\end{frame}
\begin{frame}
\frametitle{Stateful Nodes: Transition Paths}
\begin{itemize}
\item {
Filled line transitions indicate local requests remote to perform
state transition.
}
\item {
Dashed line transitions indicate local implicitly transitions prior
to sending request to remote.
}
\item {
\textit{Non-committal} path concerns about read-only and
copy-on-write sharing. Sharers cannot make global modification to
cached local data.
}
\item {
\textit{Invalidation} path is duo with commit operations (due to
write-invalidation).
}
\item {
\textit{Committal} path concerns about global write sharing. Only
one writer is allowed to write and commit at one time.
}
\item {
Problem: How exactly to integrate RDMA remote read/write into this?
}
\end{itemize}
\end{frame}
% Part 3: Progress
@ -230,9 +380,25 @@
\begin{frame}
\frametitle{Progress}
\begin{itemize}
\item {
Goal: in-kernel implementation of software cache-coherency via
non-coherent RDMA hardware.
}
\item {
Optimistic Goal: in-kernel implementation of memory model in DSM.
}
\item {
Progress: studied and isolated mechanism for data cache
invalidation/flushing in ARM64, which allows the DSM to run in
heterogeneous ISA clusters.
}
\item {
Integration with kernel \& main DSM kernel module remains at hand:
is it absolutely necessary to export new symbols for such an
important operation?
}
\end{itemize}
\end{frame}
\begin{frame}
@ -266,5 +432,9 @@
\end{frame}
% Part 4: Future Work
% =============================================================================
% References
\end{document}