Datensatz

Zusammenfassung

On practical parallel computers, the time for routing a distribution
of sufficiently large packets can be approximated by $\max\{T_f,
T_b\}$. Here $T_f$ is proportional to the maximum number of bytes a
PU sends and receives, and $T_b$ is proportional to the maximum
number of bytes a connection in the network has to transfer.
We show that several important routing patterns can be performed
by a sequence of balanced all-to-all routings and analyze how
to optimally perform these under the above cost-model. We concentrate
on dimension-order routing on meshes, and assume that the routing
pattern must be decomposed into a sequence of permutations.
The developed strategy has been implemented on the Intel Paragon.
In comparison with the trivial strategy, in which $\mi{PU}_i$ routes
to $\mi{PU}_{(i + t) \bmod P}$ in permutation~$t$, $1 \leq t < P$,
one gains between $10$ and $20\%$.