US 6,748,460 B2 · Initiative passing in an I/O operation without the overhead of an interrupt

Abstract

Apparatus, method and program product for use in passing initiative to a processor for handling an I/O request for an I/O operation for sending data between a main storage and one or more devices. A hierarchy of vectors registers I/O requests by the devices to send or receive data from the main storage. The hierarchy of vectors has one or more lower levels and a highest level. Each device sets a vector in the lowest level of the hierarchy for registering an I/O request, the setting of a vector in the lowest level being reflected up the hierarchy to the highest level, thereby registering I/O requests on any lower level of the hierarchy in the highest level. A dispatcher polls the hierarchy in high to low order with the dispatcher passing initiative to the processor to handle I/O requests registered in said hierarchy responsive to registering of an I/O request on the lowest level as reflected to the highest level of said hierarchy.

Claims20

Dependent claims

An apparatus comprising:

a processor handling an I/O request in an I/O operation;
main storage controlled by the processor for storing data;
one or more I/O devices for sending data to or receiving data from said main storage;
a hierarchy of vectors registering I/O requests by said devices to send or receive data from said main storage, said hierarchy of vectors having one or more lower levels and a highest level, each device setting a vector in the lowest level of said hierarchy for registering an I/O request, the setting of a vector in the lowest level being reflected up the hierarchy to the highest level of said hierarchy thereby registering I/O requests on any lower level of said hierarchy in the highest level;
and
a dispatcher polling said hierarchy in high to low order, said dispatcher passing initiative to the processor to handle I/O requests registered in said hierarchy responsive to registering of an I/O request on said lowest level as reflected to the highest level of said hierarchy.

3 more elements

A method for passing initiative to a processor to handle an I/O request in an I/O operation, said method comprising:

sending in I/O operations initiated by I/O requests, data between one or more devices and a main storage under control of a main processor;
registering in a hierarchy of vectors, I/O requests by said devices to send or receive data from said main storage, said hierarchy of vectors having one or more lower levels and a highest level, each device being associated with a vector in the lowest level, said registering comprising
setting a vector in the lowest level of said hierarchy registering an I/O request from the vector's associated device, and
reflecting the I/O request up the hierarchy to the highest level of said hierarchy thereby registering I/O requests on any lower level of said hierarchy in the highest level;
polling by a dispatcher said hierarchy in high to low order for registered I/O requests;
and
passing initiative to the processor to handle I/O requests registered in said hierarchy responsive to registering of an I/O request on said lowest level as reflected to the highest level of said hierarchy.

4 more elements

A program product usable with a system for passing initiative to a processor to handle an I/O request in an I/O operation, said I/O operation for sending data between a main storage and one or more devices, said program product comprising:

a computer readable medium having recorded thereon computer readable program code means for performing the method comprising:
registering in a hierarchy of vectors, I/O requests by said devices to send or receive data from said main storage, said hierarchy of vectors having one or more lower levels and a highest level, each device being associated with a vector in the lowest level, said registering comprising
setting a vector in the lowest level of said hierarchy registering an I/O request from the vector's associated device, and
reflecting the I/O request up the hierarchy to the highest level of said hierarchy thereby registering I/O requests on any lower level of said hierarchy in the highest level;
polling said hierarchy in high to low order for registered I/O requests;
and
passing initiative to the processor to handle I/O requests registered in said hierarchy responsive to registering of an I/O request on said lowest level as reflected to the highest level of said hierarchy.

4 more elements

An apparatus for use in passing initiative to a processor for handling an I/O request for an I/O operation for sending data between a main storage and one or more devices, the apparatus comprising:

a hierarchy of vectors registering I/O requests by said devices to send or receive data from said main storage, said hierarchy of vectors having one or more lower levels and a highest level, each device setting a vector in the lowest level of said hierarchy for registering an I/O request, the setting of a vector in the lowest level being reflected up the hierarchy to the highest level of said hierarchy thereby registering I/O requests on any lower level of said hierarchy in the highest level;
and
a dispatcher polling said hierarchy in high to low order, said dispatcher passing initiative to the processor to handle I/O requests registered in said hierarchy responsive to registering of an I/O request on said lowest level as reflected to the highest level of said hierarchy.

Dependencies are inferred from the claim text.

Initiative passing in an I/O operation without the overhead of an interrupt

Life of this patent

Initiative passing in an I/O operation without the overhead of an interrupt

Life of this patent

Abstract

Claims20