Method and apparatus for efficient bus arbitration

A program storage device storing instructions that when executed by a computer perform the method comprising:

• assigning a desired weighted bandwidth to a first device which transfers data over the common bus, wherein said desired weighted bandwidth reflects selected performance abilities and requirements of said first device;
• assigning a desired weighted bandwidth to a second device which transfers data over the common bus, wherein said desired weighted bandwidth reflects selected performance abilities and requirements of said second device;
• arbitrating access to the common bus based upon the desired weighted bandwidths of the first and second devices;
• and
• dynamically adjusting the desired weighted bandwidths of the first and second devices during operation based upon a history of a measure of data transfer over the common bus by at least one of the first and second devices, occurring within a defined period.

A program storage device storing instructions that when executed by a computer perform the method comprising:

• assigning each of a plurality of devices a priority rank;
• setting a current weighted bandwidth of each of said plurality of devices equal to a desired weighted bandwidth;
• servicing a request to access a common bus from a first device of said plurality of devices, said first device having the highest priority rank among a set of requesting devices;
• decrementing said current weighted bandwidth of said first device;
• setting said priority rank of said first device equal to a lowest value if said decremented current weighted bandwidth of said first device is equal to a minimum value and increasing said priority rank of a set of devices which previously had a lower priority rank than said first device;
• setting said current bandwidth of said first device equal to said desired weighted bandwidth;
• and
• dynamically adjusting said desired weighted bandwidth of said first device during operation based upon a history of actual usage of said common bus by said first device, wherein said history comprises a record of bus accesses granted to said first device, and a record of bus accesses granted to others of said plurality of devices, occurring within a defined period.

A program storage device storing instructions that when executed by a computer perform the method comprising:

• determining a rate at which a first device is capable of transferring data over a common bus;
• determining a rate at which a second device is capable of transferring data over said common bus;
• assigning a desired weighted bandwidth to said first device and a desired weighted bandwidth to said second device based upon said rate of said first and second devices;
• arbitrating access to said common bus based upon said desired weighted bandwidth of said first and second devices;
• and
• dynamically adjusting said desired weighted bandwidth of said first and second devices during operation based upon a history of actual usage of said common bus by said first and second devices, wherein said history comprises multiple bus accesses granted to at least one of said first and second devices.

An apparatus for controlling access to a common bus comprising:

• means for assigning each of a plurality of devices a priority rank;
• means for setting a current weighted bandwidth of each of said plurality of devices equal to a desired weighted bandwidth;
• means for servicing a request to access said common bus from a first device of said plurality of devices, said first device having the highest priority rank among a set of requesting devices;
• means for decrementing said current weighted bandwidth of said first device;
• means for setting said priority rank of said first device equal to a lowest rank if said decremented current weighted bandwidth of said first device is equal to a minimum value and increasing said priority rank of a set of devices which previously had a lower priority rank that said first device;
• means for setting said current weighted bandwidth of said first device equal to said desired weighted bandwidth;
• and
• means for dynamically adjusting said desired weighted bandwidth of said first device during operation based upon a history of actual usage of said common bus by said first device, wherein said history comprises a record of bus accessed granted to said first device, and a record of bus accesses granted to others of said plurality of devices, occurring within a defined period.

An apparatus for regulating access to a common bus comprising means for determining a rate at which a first device is capable of transferring data over said common bus;

• means for determining a rate at which a second device is capable of transferring data over said common bus;
• means for assigning a desired weighted bandwidth to said first device and a desired weighted bandwidth to said second device based upon said rate of said first and second devices;
• means for arbitrating access to said common bus based upon said desired weighted bandwidth of said first and second devices;
• and
• means for dynamically adjusting said desired weighted bandwidth of said first and second devices during operation based upon a history of actual usage of said common bus by said first and second devices, wherein said history comprises multiple bus accesses granted to at least one of said first and second devices.