Abstract: A cache stores 2?J-byte cache lines has an array of 2?N sets each holds tags each X bits and 2?W ways. An input receives a Q-bit address, MA[(Q?1):0], having a tag MA[(Q?1):(Q?X)] and index MA[(Q?X?1):J]. Q is at least (N+J+X?1). Set selection logic selects one set using the index and tag LSB; comparison logic compares all but the LSB of the tag with all but the LSB of each tag in the selected set and indicates a hit if a match; allocation logic, when the comparison logic indicates there is not a match: allocates into any of the 2?W ways of the selected set when operating in a first mode; and into a subset of the 2?W ways of the selected set when operating in a second mode. The subset of is limited based on bits of the tag portion.

Abstract: A microprocessor comprises a cache including a tag array; a tag pipeline that arbitrates access to the tag array; and a pattern detector. The pattern detector comprises a register; a decoder that decodes transaction type identifiers of tagpipe arbs advancing through the tag pipeline; and an accumulator that accumulates into the register the transaction type identifiers of a plurality of tagpipe arbs that advance through the tag pipeline.

Abstract: A set associative cache memory, comprising: an array of storage elements arranged as M sets by N ways, each set belongs in one of L mutually exclusive groups; an allocation unit allocates the storage elements in response to memory accesses that miss in the cache; each memory access has an associated memory access type (MAT) of a plurality of predetermined MAT; a mapping, for each group of the L mutually exclusive groups: for each MAT, associates the MAT with a subset of the N ways; and for each memory access, the allocation unit allocates into a way of the subset of ways that the mapping associates with the MAT of the memory access and with one of the L mutually exclusive groups in which the selected set belongs.

Abstract: A microprocessor comprises a cache including a tag array; a tag pipeline that arbitrates access to the tag array; and a pattern detector. The pattern detector comprises snapshot capture logic that captures snapshots of tagpipe arbs—including information about whether the tagpipe arb is a load, snoop, store or other arb type and whether the tagpipe arb completed or replayed—and a plurality of configurable register modules operable to store user-configured snapshot patterns. Configuration logic enables a user to specify, for each configurable register module, properties of tagpipe arbs for the pattern detector to detect as well as dependencies between the configurable register modules. A register module becomes triggered if a tagpipe arb or pattern of tagpipe arbs meets the user-specified properties for the register module and if any other register module on which the register module depends is also in a triggered state.

Abstract: A cache memory comprising: a mode input indicates in which of a plurality of allocation modes the cache memory is to operate; a set-associative array of entries having a plurality of sets by W ways; an input receives a memory address comprising: an index used to select a set from the plurality of sets; and a tag used to compare with tags stored in the entries of the W ways of the selected set to determine whether the memory address hits or misses; and allocation logic, when the memory address misses in the array: selects one or more bits of the tag based on the allocation mode; performs a function, based on the allocation mode, on the selected bits of the tag to generate a subset of the W ways of the array; and allocates into one way of the subset of the ways of the selected set.

Abstract: An associative cache memory, comprising: an array of storage elements arranged as M sets by N ways; an allocation unit allocates the storage elements in response to memory accesses that miss in the cache memory. Each memory access selects a set. Each memory access has an associated memory access type (MAT) of a plurality of predetermined MATs. Each valid storage element has an associated MAT; a mapping that includes, for each MAT, a MAT priority. In response to a memory access that misses in the array, the allocation unit: determines a most eligible way and a second most eligible way of the selected set for replacement based on a replacement policy; and replaces the second most eligible way rather than the most eligible way when the MAT priority of the most eligible way is greater than the MAT priority of the second most eligible way.

Abstract: A microprocessor comprises a cache including a tag array; a tagpipe that arbitrates access to the tag array; and a logic analyzer for investigating a starvation, livelock, or deadlock condition. The logic analyzer, which comprises read logic coupled to the tagpipe, is configured to record snapshots of transactions to access the tag array.

Abstract: A microprocessor comprises a plurality of queues containing transient transaction state information about cache-accessing transactions; a plurality of detectors coupled to the plurality of queues and monitoring the plurality of queues for one or more likely starvation, livelock, or deadlock conditions; and a plurality of recovery logic modules operable to implement one or more recovery routines when the detectors identify one or more likely starvation, livelock, or deadlock conditions.

Abstract: A processor includes a cache memory having a plurality of entries. Each of the entries holds data of a cache line, a state of the cache line and a tag of the cache line. The cache memory includes an engine comprising one or more finite state machines. The processor also includes an interface to a bus over which the processor writes back modified cache lines from the cache memory to the system memory in response to encountering an architectural writeback and invalidate instruction. The processor also invalidates the state of the entries of the cache memory in response to encountering the architectural writeback and invalidate instruction. In response to being instructed to perform a cache diagnostic operation, for each entry of the entries, the engine writes the state and the tag of the entry on the bus and does not invalidate the state of the entry.

Abstract: A processor includes a plurality of processing cores and a cache memory shared by the plurality of processing cores. The cache memory comprises a size engine that receives a respective request from each of the plurality of processing cores to perform an operation associated with the cache memory. The size engine fuses the respective requests from two or more of the plurality of processing cores into a fused request. To perform the fused request the size engine performs a single instance of the operation and notifies each of the two or more of the plurality of processing cores that its respective request has been completed when the single instance of the operation is complete.

Abstract: A fully associative cache memory, comprising: an array of storage elements; an allocation unit that allocates the storage elements in response to memory accesses that miss in the cache memory. Each memory access has an associated memory access type (MAT) of a plurality of predetermined MATs. Each valid storage element of the array has an associated MAT. For each MAT, the allocation unit maintains: a counter that counts of a number of valid storage elements associated with the MAT; and a corresponding threshold. The allocation unit allocates into any of the storage elements in response to a memory access that misses in the cache, unless the counter of the MAT of the memory access has reached the corresponding threshold, in which case the allocation unit replaces one of the valid storage elements associated with the MAT of the memory access.