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Effective Task Distribution and Execution Mechanism for Programmers Hierarchical Interactive Graphics Processing System on a Multiprocessor

IP.com Disclosure Number: IPCOM000105412D
Original Publication Date: 1993-Jul-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 6 page(s) / 131K

Publishing Venue

IBM

Related People

Kawase, K: AUTHOR [+2]

Abstract

Disclosed is a effective Traversal state list (TSL) push, pop and dispatch mechanism for PHIGS processing on a multiprocessor. It is important to reduce the overhead of TSL handling for PHIGS processing. Fig. 1 shows a typical PHIGS display-list that is sent from a workstation to a graphics subsystem. The TSL shows the state of the drawing attributes and the accumulation of the attributes in the display-list. In a multiprocessor system, each Processor Element

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Effective Task Distribution and Execution Mechanism for Programmers Hierarchical Interactive Graphics Processing System on a Multiprocessor

      Disclosed is a effective Traversal state list (TSL) push, pop
and dispatch mechanism for PHIGS processing on a multiprocessor.  It
is important to reduce the overhead of TSL handling for PHIGS
processing.  Fig. 1 shows a typical PHIGS display-list that is sent
from a workstation to a graphics subsystem.  The TSL shows the state
of the drawing attributes and the accumulation of the attributes in
the display-list.  In a multiprocessor system, each Processor Element

(PE) must have its own copy of the TSL.  The way in which the TSL is
dispatched to PEs is therefore important.  The simplest way to
maintain the TSL is for the dispatcher to copy it through the shared
bus and dispatch it to PEs before every task dispatch.  However, the
size of the TSL is about 1K bytes.  Therefore, a simple
copy-and-dispatch method is not effective, because of the overhead of
copying to memory through the shared bus.  To reduce the time taken
to copy the TSL, the triple TSL store (TTS) method was invented.
This makes it possible to copy the TSL in the background, so the time
taken for copying is negligible.  However, TTS is only effective for
normal drawing primitives.  The "TSL push" and "TSL pop" primitives
requires swapping of the whole TSL through the shared bus, and still
have a large memory copy overhead.

      Fig. 2 shows an overview of the disclosed system.  The
dispatcher reads the display-list, which consists of the "set
attribute command" and the "draw primitive command", from the
external bus and processes them seqencially.  When the dispatcher
finds a "set attribute command", it puts that command on the shared
bus as a broadcast message.  Every TTS residing in a PE always
watches the shared bus, and takes the attribute into the master copy
(Fig. 3).  The TSC also watches the shared bus and takes the
attribute.

      The disclosed method uses two major components.  One is the TTS
with a modified bit and...