Commit 1d94fe9e authored by Xunnamius (Zara)'s avatar Xunnamius (Zara)

overhead numbers in

parent b364f10e
......@@ -166,30 +166,28 @@ region (see: \secref{usecases}).
\subsection{Cipher Switching Overhead}\label{subsec:3}
From the results of the previous three experiments, we calculate that Forward
switching has between \TODO{X} and \TODO{Y} latency overhead compared to
baseline I/O, with average overhead at \TODO{XX} for 40MB, 5MB and 512KB
workloads and average overhead at \TODO{YY} for 4KB read workloads and
\TODO{YYY} for 4KB write workloads. There is no spatial overhead with the
Forward switching strategy.
Similarly, we calculate that Selective switching has between \TODO{X} and
\TODO{Y} latency overhead compared to baseline I/O, with average overhead at
\TODO{XX} for 40MB, 5MB and 512KB workloads and average overhead at \TODO{YY}
for 4KB read workloads and \TODO{YYY} for 4KB write workloads. Read overhead.
Spatial overhead was half of all writable space on the backing store.
Finally, we calculate that Mirrored switching has between \TODO{X} and \TODO{Y}
read latency overhead and between \TODO{X} and \TODO{Y} write overhead compared
to baseline I/O, with average overhead at \TODO{XX}/\TODO{XXX} for 40MB, 5MB and
512KB read/write workloads and average overhead at \TODO{YY}/\TODO{YYY} for 4KB
read/write workloads. Spatial overhead was half of all writable space on the
backing store.
switching has average overhead at 0.08x/0.10x for 40MB, 5MB and 512KB read/write
workloads compared to baseline I/O, demonstrating SwitchCrypt's amortization of
cipher switching costs. Average overhead is 0.38x/0.44x for 4KB read/write
workloads when SwitchCrypt is unable to amortize cost. There is no spatial
overhead with the Forward switching strategy.
Similarly, we calculate that Selective switching has average overhead at 0x/0.3x
for 40MB, 5MB and 512KB read/write workloads compared to baseline I/O. Average
overhead is 0.22x/0.71x for 4KB read/write workloads. Spatial overhead in our
experiment was half of all writable space on the backing store.
Finally, we calculate that Mirrored switching has average overhead at
0.25x/0.61x for 40MB, 5MB and 512KB read/write workloads compared to baseline
I/O, with high write latency due to mirroring. Average overhead is 0.55x/0.77x
for 4KB read/write workloads. Spatial overhead in our experiment was half of all
writable space on the backing store.
These overhead numbers are the penalty paid for the additional flexibility of
being able to reach configurations points that are simply unachievable without
being able to reach configurations points that are unachievable without
SwitchCrypt. We believe SwitchCrypt's design keeps these overheads acceptably
low, achieving the desired goal of flexibly navigating latency/security
tradeoffs for FDE.
low in practice, achieving the desired goal of flexibly navigating
latency/security tradeoffs for FDE.
\subsection{Augmented Threat Analysis}\label{subsec:4}
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