Browse Prior Art Database

Message Broadcast Mechanism Using a Shared Bus

IP.com Disclosure Number: IPCOM000100823D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 90K

Publishing Venue

IBM

Related People

Shimizu, S: AUTHOR

Abstract

This article describes a new message broadcast mechanism which enables an effective and flexible one-to-many message broadcast for MP signaling.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Message Broadcast Mechanism Using a Shared Bus

       This article describes a new message broadcast mechanism
which enables an effective and flexible one-to-many message broadcast
for MP signaling.

      For a shared-memory multiprocessor, a message-passing hardware
mechanism is necessary to allow the processors to communicate
asynchronous events or to interrupt each other.

      This new message-passing mechanism has the following two
features:
1.   The message is broadcast to all processors specified as the
destinations. Furthermore, destinations can be easily classified into
various groups, and, therefore, flexible broadcasting can be
realized.
2.   The message is received or discarded by the destination
processors, according to the state of the receiver's buffer (i.e.,
full or empty). This handshake between the sender and a number of
receivers can be very easily achieved by using a wired-OR signal
line. Thus, no overhead for the handshake is needed.

      Moreover, this mechanism can easily provide two kinds of
message broadcast protocols for realizing flexible MP signaling. One
is called Everybody messaging, and the other is called Anybody
messaging.

      In Everybody messaging, all specified receivers receive the
message and generate an interrupt to the processor only when all the
specified receivers can receive the message. If any receiver cannot
receive the message, none of them can do so. The sender can recognize
whether the message was received or not with no overhead. For
instance, this protocol is important for an operating system to
maintain TLB consistency and also for multiprocessing programming
language that can interrupt executions of other processors.

      In Anybody messaging, each receiver receives the message and
generates an interrupt when it can receive the message. The sender
recognizes that the message was successfully received when one or
more receivers can receive the message. If no receiver can receive
the message, the sender also recognizes that the message was not
received by any receiver. For instance, this protocol is useful for
asking some serv...