19 lines
877 B
TeX
19 lines
877 B
TeX
\section{Resource models}
|
|
|
|
As we saw earlier in \qtodo{ref}, the behaviour of a CPU's backend can be,
|
|
throughput-wise, characterized by the behaviour of its ports. Thus, a
|
|
throughput model of the backend consists in a mapping of the ISA's instructions
|
|
to execution ports of the backend, called a \emph{port mapping}.
|
|
|
|
The mapping, however, is not direct: we also saw in \qtodo{ref} that
|
|
instructions are themselves broken down into a number of \uops{}, which all
|
|
have to be executed. Each of those \uops{} are then scheduled on one of the
|
|
compatible execution ports of the CPU. A port mapping, thus, is actually a
|
|
tripartite graph: a first layer mapping instructions to \uops{}, followed by a
|
|
second layer mapping \uops{} to ports. In
|
|
\autoref{fig:port_mapping_excerpt_skx_tri},
|
|
|
|
\begin{figure}
|
|
\centering
|
|
\includegraphics[width=\textwidth]{p016_tri.svg}
|
|
\end{figure}
|