Increased bandwidth for multi-processor access of a common resource

Claim 1

A subgroup access controller used in combination with an allocation controller, said subgroup access controller providing sharing of multiple duplicate copy resources by pluralities of CPUs, said allocation controller including said plurality of CPUs including first, second and third groups each group including first and second portions; at least three resources each having two duplicate copies, each to be selectively connected to any CPU of said plurality; first arbitration means including first, second and third duplicated groups, each duplicated group of first arbitration means connected to a corresponding group of CPUs; said first arbitration means operated in response to resource request signals from said plurality of CPUs to provide for selection of one CPU per CPU group; a plurality of CPU buses including first, second and third groups corresponding to said CPU groups, each bus connected between a particular CPU and said first arbitration means, each CPU bus including a control portion and an address/data portion; at least three pair of group buses, each bus pair corresponding to one said CPU group and said corresponding CPU buses, and each group bus connected between a particular CPU through said corresponding CPU bus via said first arbitration means and connected to one copy of said duplicate copy resources via one said group bus, each group bus further connected to said other group buses of said corresponding groups; one group bus of each said pair further connected to a first copy of said duplicate copy resources and another group bus of each said pair further connected to a second copy of said duplicate copy resources; second arbitration means connected between each of said duplicate copy resources and each group of first arbitration means and said second arbitration means operated in response to said operation of said first arbitration means to select one of said requesting CPUs of said different CPU groups for connection to said first and said second copies of one selected duplicate copy resource via one said pair of group buses and said corresponding CPU buses; said group bus pair connected to said requesting CPU via said corresponding CPU bus through said first arbitration means and said second arbitration means and connected to said duplicate copy resources to establish bus connection between said one selected CPU and said selected duplicate copy resources for the transmission of data to and from said resources; each of said second arbitration circuits operated on a rotational basis to allocate access of said selected duplicate copy resources to said requesting CPU; and clock means for generating a clock signal of a predetermined frequency, said subgroup access controller comprising: means for detecting simultaneous access requests of a CPU of each of said first and second portions of said CPU groups, said means for detecting connected to said first arbitration means and being operated in response to said simultaneous access requests to produce a contention signal; means for disabling connected to said means for detecting, to said first arbitration means and to said clock means, said means for disabling being operated in response to said contention signal and to an indication that a CPU of said first portion of said group was previously granted access to said resources to inhibit transmission of said clock signal to said first arbitration means corresponding to said first portion of CPUs; and means for enabling connected to said means for detecting, to said first arbitration means and to said clock means, said means for enabling being operated in response to said contention signal and to indication that a CPU of said first portion of said group was previously granted access to said resources to transmit said clock signal to said first arbitration means corresponding to said second portion of CPUs.