\documentclass{article}
\usepackage{fullpage}

\title{Sample Performance Study}
\author{High Performance Computing Facility\\University of Maryland, Baltimore County}
\date{}

\begin{document}
\maketitle

\begin{table}[h]
\centering
\caption{%
Performance by number of processes used with 1~process per node
except for $p=2$ which uses 2~processes per node,
and $p=256$ which uses 4~processes per node
}
\label{tab:npn1}
\begin{tabular}{rrrrrrrrrr}
\hline
\multicolumn{10}{l}{(a) Wall clock time in seconds} \\
\multicolumn{1}{r}{$N$} &
\multicolumn{1}{r}{$p = 1$} &
\multicolumn{1}{r}{$p = 2$} &
\multicolumn{1}{r}{$p = 4$} &
\multicolumn{1}{r}{$p = 8$} &
\multicolumn{1}{r}{$p = 16$} &
\multicolumn{1}{r}{$p = 32$} &
\multicolumn{1}{r}{$p = 64$} &
\multicolumn{1}{r}{$p = 128$} &
\multicolumn{1}{r}{$p = 256$} \\
\hline
1024 & 00:17:04  & 00:08:32  & 00:04:16  & 00:02:08  & 00:01:04  & 00:00:32  &      ---  &      ---  &      ---  \\ 
2048 & 00:34:08  & 00:17:04  & 00:08:32  & 00:04:16  & 00:02:08  & 00:01:04  &      ---  &      ---  &      ---  \\ 
4096 & 01:08:16  & 00:34:08  & 00:17:04  & 00:08:32  & 00:04:16  & 00:02:08  &      ---  &      ---  &      ---  \\ 
\hline
\end{tabular}
\end{table}


\begin{table}[h]
\centering
\caption{%
Performance by number of processes used with 2~processes per node
except for $p=1$ which uses 1~process per node,
and $p=256$ which uses 4~processes per node
}
\label{tab:npn2}
\begin{tabular}{rrrrrrrrrr}
\hline
\multicolumn{10}{l}{(a) Wall clock time in seconds} \\
\multicolumn{1}{r}{$N$} &
\multicolumn{1}{r}{$p = 1$} &
\multicolumn{1}{r}{$p = 2$} &
\multicolumn{1}{r}{$p = 4$} &
\multicolumn{1}{r}{$p = 8$} &
\multicolumn{1}{r}{$p = 16$} &
\multicolumn{1}{r}{$p = 32$} &
\multicolumn{1}{r}{$p = 64$} &
\multicolumn{1}{r}{$p = 128$} &
\multicolumn{1}{r}{$p = 256$} \\
\hline
1024 & 00:17:04  & 00:08:32  & 00:04:16  & 00:02:08  & 00:01:04  & 00:00:32  & 00:00:16  &      ---  &      ---  \\ 
2048 & 00:34:08  & 00:17:04  & 00:08:32  & 00:04:16  & 00:02:08  & 00:01:04  & 00:00:32  &      ---  &      ---  \\ 
4096 & 01:08:16  & 00:34:08  & 00:17:04  & 00:08:32  & 00:04:16  & 00:02:08  & 00:01:04  &      ---  &      ---  \\ 
\hline
\end{tabular}
\end{table}


\begin{table}[h]
\centering
\caption{%
Performance by number of processes used with 4~processes per node
except for $p=1$ which uses 1~process per node,
and $p=2$ which uses 2~processes per node
}
\label{tab:npn4}
\begin{tabular}{rrrrrrrrrr}
\hline
\multicolumn{10}{l}{(a) Wall clock time in seconds} \\
\multicolumn{1}{r}{$N$} &
\multicolumn{1}{r}{$p = 1$} &
\multicolumn{1}{r}{$p = 2$} &
\multicolumn{1}{r}{$p = 4$} &
\multicolumn{1}{r}{$p = 8$} &
\multicolumn{1}{r}{$p = 16$} &
\multicolumn{1}{r}{$p = 32$} &
\multicolumn{1}{r}{$p = 64$} &
\multicolumn{1}{r}{$p = 128$} &
\multicolumn{1}{r}{$p = 256$} \\
\hline
1024 & 00:17:04  & 00:08:32  & 00:04:16  & 00:02:08  & 00:01:04  & 00:00:32  & 00:00:16  & 00:00:08  &      ---  \\ 
2048 & 00:34:08  & 00:17:04  & 00:08:32  & 00:04:16  & 00:02:08  & 00:01:04  & 00:00:32  & 00:00:16  &      ---  \\ 
4096 & 01:08:16  & 00:34:08  & 00:17:04  & 00:08:32  & 00:04:16  & 00:02:08  & 00:01:04  & 00:00:32  &      ---  \\
\hline
\end{tabular}
\end{table}


\begin{table}[h]
\centering
\caption{%
Performance by number of processes used with 8~processes per node
except for $p=1$ which uses 1~process per node,
$p=2$ which uses 2~processes per node, and
$p=4$ which uses 4~processes per node.}
\label{tab:npn8}
\begin{tabular}{rrrrrrrrrr}
\hline
\multicolumn{10}{l}{(a) Wall clock time in seconds} \\
\multicolumn{1}{r}{$N$} &
\multicolumn{1}{r}{$p = 1$} &
\multicolumn{1}{r}{$p = 2$} &
\multicolumn{1}{r}{$p = 4$} &
\multicolumn{1}{r}{$p = 8$} &
\multicolumn{1}{r}{$p = 16$} &
\multicolumn{1}{r}{$p = 32$} &
\multicolumn{1}{r}{$p = 64$} &
\multicolumn{1}{r}{$p = 128$} &
\multicolumn{1}{r}{$p = 256$} \\
\hline
1024 & 00:17:04  & 00:08:32  & 00:04:16  & 00:02:08  & 00:01:04  & 00:00:32  & 00:00:16  & 00:00:08  & 00:00:04  \\ 
2048 & 00:34:08  & 00:17:04  & 00:08:32  & 00:04:16  & 00:02:08  & 00:01:04  & 00:00:32  & 00:00:16  & 00:00:08  \\ 
4096 & 01:08:16  & 00:34:08  & 00:17:04  & 00:08:32  & 00:04:16  & 00:02:08  & 00:01:04  &      ---  &      ---  \\ 
\hline
\end{tabular}
\end{table}

\end{document}
