Abstract: Methods and apparatuses are disclosed for direct access to cache memory. Embodiments include receiving, by a direct access manager that is coupled to a cache controller for a cache memory, a region scope zero command describing a region scope zero operation to be performed on the cache memory; in response to receiving the region scope zero command, generating a direct memory access region scope zero command, the direct memory access region scope zero command having an operation code and an identification of the physical addresses of the cache memory on which the operation is to be performed; sending the direct memory access region scope zero command to the cache controller for the cache memory; and performing, by the cache controller, the direct memory access region scope zero operation in dependence upon the operation code and the identification of the physical addresses of the cache memory.

Abstract: In a disclosed example of a method, a requested value of a target register may be specified as a precondition to performing a requested read or write operation. The requested read or write operation may be generated by a requesting device, such as a processor, and sent over a bus to a peripheral device containing the target register. The target register may be polled internally to the peripheral device without generating additional bus traffic between the requesting device and the peripheral device. A ring topology may be used to internally poll the target register and to perform the requested read or write operation when the polled value of the target register equals the requested value.

Abstract: A novel and useful cost effective mechanism for detecting the livelock/starvation of transactions in a ring shaped interconnect that utilizes minimal logic resources. Rather than monitor all transactions concurrently in the ring, the mechanism monitors only a single transaction in the ring. A sampling point is located at a point in the ring which contains a set of N latches. If the monitored transaction is not being starved, it is released and the detection logic moves on the next candidate transaction in round robin fashion. If the monitored transaction passes the sampling point a threshold number of times, it is deemed to be starved and a starvation prevention handling procedure is activated. By traversing the entire ring a single transaction at a time, all starving transactions will eventually be detected with an upper limit on the detection time of O(N2).

Abstract: One embodiment provides a cached memory system including a memory cache and a plurality of read-claim (RC) machines configured for performing read and write operations dispatched from a processor. According to control logic provided with the cached memory system, a hazard is detected between first and second read or write operations being handled by first and second RC machines. The second RC machine is suspended and a subset of the address bits of the second operation at specific bit positions are recorded. The subset of address bits of the first operation at the specific bit positions are broadcast in response to the first operation being completed. The second operation is then re-requested.

Abstract: Methods, apparatuses, and computer program products are disclosed for cache management. Embodiments include receiving, by a cache controller, a request to insert a new cache line into a cache; determining, by the cache controller, whether the new cache line is associated with a forced injection; in response to determining that the new cache line is associated with a forced injection, accepting, by the cache controller, the insertion of the new cache line into the cache; and in response to determining that the new cache line is not associated with a forced injection, determining, by the cache controller, whether to accept the insertion of the new cache line based on a comparison of an address of the new cache line to a predefined range of addresses.

Abstract: Ensuring forward progress of token-required cache operations in a shared cache, including: snooping an instruction to execute a token-required cache operation; determining if a snoop machine is available and if the snoop machine is set to a reservation state; if the snoop machine is available and the snoop machine is in the reservation state, determining whether the instruction to execute the token-required cache operation owns a token or is a joint instruction; if the instruction is a joint instruction, instructing the operation to retry; if the instruction to execute the token-required cache operation owns a token, dispatching a cache controller; determining whether all required cache controllers of relevant compute nodes are available to execute the instruction; executing the instruction if the required cache controllers are available otherwise not executing the instruction.

Abstract: Methods and apparatuses are disclosed for direct access to cache memory. Embodiments include receiving, by a direct access manager that is coupled to a cache controller for a cache memory, a region scope zero command describing a region scope zero operation to be performed on the cache memory; in response to receiving the region scope zero command, generating a direct memory access region scope zero command, the direct memory access region scope zero command having an operation code and an identification of the physical addresses of the cache memory on which the operation is to be performed; sending the direct memory access region scope zero command to the cache controller for the cache memory; and performing, by the cache controller, the direct memory access region scope zero operation in dependence upon the operation code and the identification of the physical addresses of the cache memory.

Abstract: Acquiring access to a token controlled system resource, including: receiving, by a token broker, a command that requires access to the token controlled system resource, where the token broker is automated computing machinery for acquiring tokens and distributing the command to the token controlled system resource for execution; identifying, by the token broker, a first need state, the first need state indicating that the token broker requires access to the token controlled system resource to which the token broker does not possess a token; requesting, by the token broker, a configurable number of tokens to gain access to the token controlled system resource, without dispatching an operation handler for executing the command until at least one token is acquired; assigning, by the token broker, an acquired token to the operation handler; and dispatching, by the token broker, the operation handler and its assigned token for executing the command.

Abstract: An L2 cache, method and computer program product for transferring an inbound bus operation to a processor side handling machine. The method includes a bus operation handling machine accepting the inbound bus operation received over a system interconnect, the bus operation handling machine identifying a demand operation of the processor side handling machine that will complete the bus operation, the bus operation handling machine sending the identified demand operation to the processor side handling machine, and the processor side handling machine performing the identified demand operation.

Abstract: A number of hypervisor register fields are set to specify which processor cores are allowed to generate a number of performance events for a particular thread group. A plurality of threads for an application running in the computing environment to a plurality of thread groups are configured by a plurality of thread group fields in a plurality of control registers. A number of counter sets are allowed to count a number of thread group events originating from one of a shared resource and a shared cache are specified by a number of additional hypervisor register fields.

Abstract: Sampled instruction address registers are shared among multiple threads executing on a plurality of processor cores. Each of a plurality of sampled instruction address registers are assigned to a particular thread running for an application on the plurality of processor cores. Each of the sampled instruction address registers are configured by storing in each of the sampled instruction address registers a thread identification of the particular thread in a thread identification field and a processor identification of a particular processor on which the particular thread is running in a processor identification field.

Abstract: Counter registers are shared among multiple threads executing on multiple processor cores. An event within the processor core is selected. A multiplexer in front of each of a number of counters is configured to route the event to a counter. A number of counters are assigned for the event to each of a plurality of threads running for a plurality of applications on a plurality of processor cores, wherein each of the counters includes a thread identifier in the interrupt thread identification field and a processor identifier in the processor identification field. The number of counters is configured to have a number of interrupt thread identification fields and a number of processor identification fields to identify a thread that will receive a number of interrupts.

Abstract: A method and system for processing data. In one embodiment, the method includes receiving a first store and receiving a second store subsequent to the first store. The method also includes generating a pointer that points to the last store that needs to retire before the second store retires, where the pointer is associated with the second store, and the last store that needs to retire is the first store.

Abstract: A method and system for processing data. In one embodiment, the method includes receiving a plurality of stores into a store queue, where each store is a result from a processor, and where the plurality of stores are destined for at least one memory address. The method also includes marking a most recent store of the plurality of stores for each unique memory address, comparing a load request against the store queue, and identifying only the most recent store for each unique memory address for the purpose of handling load-hit-store ordering hazards.

Abstract: A single unified level one instruction(s) cache in which some lines may contain traces and other lines in the same congruence class may contain blocks of instruction(s) consistent with conventional cache lines. Formation of trace lines in the cache is delayed on initial operation of the system to assure quality of the trace lines stored.

Abstract: A single unified level one instruction(s) cache in which some lines may contain traces and other lines in the same congruence class may contain blocks of instruction(s) consistent with conventional cache lines. Formation of trace lines in the cache is delayed on initial operation of the system to assure quality of the trace lines stored.

Abstract: A single unified level one instruction(s) cache in which some lines may contain traces and other lines in the same congruence class may contain blocks of instruction(s) consistent with conventional cache lines. Formation of trace lines in the cache is delayed on initial operation of the system to assure quality of the trace lines stored.

Abstract: A design structure embodied in a machine readable storage medium for designing, manufacturing, and/or testing a design for forwarding store data to loads in a pipelined processor is provided. In one implementation, a processor is provided that includes a decoder operable to decode an instruction, and a plurality of execution units operable to respectively execute a decoded instruction from the decoder. The plurality of execution units include a load/store execution unit operable to execute decoded load instructions and decoded store instructions and generate corresponding load memory operations and store memory operations. The store queue is operable to buffer one or more store memory operations prior to the one or more memory operations being completed, and the store queue is operable to forward store data of the one or more store memory operations buffered in the store queue to a load memory operation on a byte-by-byte basis.

Abstract: A method and system for creating trace triggers from non-concurrent events, the system comprising: a trace trigger mechanism including: a plurality of multiplexers for breaking down a plurality of signals into a plurality of groups of signals; a pattern match mechanism for matching the plurality of signals to form a plurality of events, and a trace array trigger control block to perform one or more functions on the plurality of independently controlled events in order to create flexible trace trigger controls from non-concurrent events to control the starting and stopping of a data gathering function such as is used to capture trace data.

Abstract: A single unified level one instruction cache in which some lines may contain traces and other lines in the same congruence class may contain blocks of instructions consistent with conventional cache lines. A mechanism is described for indexing into the cache, and selecting the desired line. Control is exercised over which lines are contained within the cache. Provision is made for selection between a trace line and a conventional line when both match during a tag compare step.