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Scheduling Controls for Pipelines in a Multiprocessing Environment

IP.com Disclosure Number: IPCOM000118296D
Original Publication Date: 1996-Dec-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 69K

Publishing Venue

IBM

Related People

Compton, SB: AUTHOR [+2]

Abstract

Disclosed is a method for resolving a class of scheduling problems associated with use of pipelines by asynchronous processes. Controls for synchronizing open and close processing of connections are used along with means to avoid deadlocks associated with said synchronizations.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 53% of the total text.

Scheduling Controls for Pipelines in a Multiprocessing Environment

      Disclosed is a method for resolving a class of scheduling
problems associated with use of pipelines by asynchronous processes.
Controls for synchronizing open and close processing of connections
are used along with means to avoid deadlocks associated with said
synchronizations.

      Controls are provided to specify individual pipe topology for
open and close time synchronization and to specify connection
specific behavior for bypassing said synchronization for deadlock
avoidance, e.g., while still 'participating' in the synchronization.
The controls are specified by parameters associated with the file
definition for the pipe and specific connection OPEN processing.  The
Input/Output (I/O) subsystem processing the pipe allocations and
OPENs takes these parameters as input and carries out the management
functions associated with these controls.
  o  Open synchronization is a pipe level specification used
      to assure the desired number of processes have connected
      to the pipe.  The parameter specifies the number of writers
      and readers which must open a pipe before their collective
      open requests can complete and they can issue I/O
      requests to the pipe.  The parameter is of the form
      OpenSync(W=i(w),R=i(r)) where i(w) is the number of
      writers required to open the pipe before open is allowed
      to complete and i(r) is the number of readers required to
      fulfill the noted condition.  Both counts must be satisfied
      for all connections to be allowed to open.  The default is
      OS(W=1,R=1).  OpenSync is meant to specify the minimum
      configuration for a pipe before execution can begin.  It
      does not preclude other connections to the pipe after
      open.  Enhancements are specifying an absolute number of
      connections, an initial configuration, and a maximum
      configuration.
  o  OpenNow is a connection specific parameter used to avoid
      deadlock...