Synergy User Manual and Tutorial. - THE CORE MEMORY

Synergy User Manual and Tutorial
FDD is a Fault Detection Daemon. It is activated by an option in the prun command to
detect worker process failures at runtime.
Synergy V3.0 requires no root privileged processes. All parallel processes assume
respective user security and resource restrictions defined at account creation. Parallel use
of multiple computers imposes no additional security threat to the existing systems.
Theoretically, there should be one object daemon for each supported object type. For the
three supported types: tuple space, pipe and files, we saved the pipe daemon by
implementing it directly in LIL. Thus, Synergy V3.0 has only two object daemons: the
Tuple Space Handler (tsh) and the File Access Handler (fah). The object daemons, when
activated, talk to parallel programs via the LIL operators under the user defined identity
(via CSL). They are potentially resource hungry. However they only "live" on the
computers where they are needed and permitted.
Optimal processor assignment is theoretically complex. Synergy's automatic processor
binding algorithm is extremely simple: unless specifically designated, it binds all tuple
space objects, one master and one worker to a single processor. Other processors run the
worker-type (with repeatable logic) processes. Since network is the bottleneck, this
binding algorithm minimizes network traffic thus promising good performance for most
applications using the current tuple matching engine. The full implementation of SLM
will have a distributed tuple matching engine that promises to fulfill a wider range of
performance requirements.
Fault tolerance is a natural benefit of the SPP design. Processor failures discovered
before a run are automatically isolated. Worker processor failures during a parallel
execution is treated in V3.0 by a "tuple shadowing" technique. Synergy V3.0 can
automatically recover the lost data from a lost worker with little overhead. This feature
brings the availability of a multiprocessor application to be equal to that of a single
processor and is completely transparent to application programs.
Synergy provides the basis for automatic load balancing. However, optimal load
balancing requires adjusting tuple sizes. Tuple size adjustments can adapt guided selfscheduling
[1], factoring [2] or fixed chunking using the theory of optimal granule size
for load balancing [3].
Synergy V3.0 runs on clusters of workstations. This evaluation copy allows unlimited
processors across multiple file systems (*requires one binary installation per file system).
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