Two-stage cache partitioning
Techniques and mechanisms to facilitate access to a cache based on a dual basis partition scheme. In an embodiment, a first one or more registers of a processor provide information which describes multiple set-wise partitions of a cache. A second one or more registers of the processor provides additional information which describes multiple way-wise partitions of the cache. A virtual cache is defined as that region of the cache which is both in a particular set-wise partition, and in a particular way-wise partition. In another embodiment, a cache agent of the processor performs operations, based on the set-wise partitioning and the way-wise partitioning, to determine a mapping of one address—which is provided in a memory access request, and which indicates a location in one virtual cache—to another address which indicates another location in a different virtual cache.
1 . A processor comprising:
a first one or more registers to provide first information which describes a set-wise partitioning of a cache;
a second one or more registers to provide second information which describes a way-wise partitioning of the cache; and
first circuitry coupled to the first one or more registers and the second one or more registers, the first circuitry to:
receive a memory access request comprising a first address; and
identify a cache line of the cache based on the first address, the set-wise
partitioning, and the way-wise partitioning;
wherein:
the first one or more registers comprise a first plurality of registers which correspond to different ones of multiple set-wise partitions, respectively;
the cache comprises multiple segments which each comprise a same total number of sets; and
for each of the first plurality of registers, the register is to provide a respective first set of bits which is to identify one or more of the multiple segments as belonging to the corresponding set-wise partition.
2 . The processor of claim 1 , wherein, for each of the first plurality of registers, the register is to further provide a respective second set of bits which is to indicate a base of the corresponding set-wise partition.
3 . The processor of claim 2 , wherein, for each of the first plurality of registers, the register is to further provide a respective third set of bits to facilitate a selection of the corresponding set-wise partition.
4 . The processor of claim 1 , wherein the first one or more registers further comprise a second plurality of registers which are each to correspond to a different respective one of the multiple set-wise partitions; and
wherein, for each register of the second plurality of registers, the register is to identify one or more conditions to an authorization of an access to the corresponding set-wise partition.
5 . The processor of claim 1 , wherein, for each set-wise partition of multiple set-wise partitions, the first one or more registers are to identify a respective plurality of addresses as corresponding to the set-wise partition.
6 . The processor of claim 1 , wherein the second one or more registers comprise a first register comprising multiple fields which correspond to different processor execution resources, respectively; and
wherein, for each of the multiple fields, the field is to provide a value indicating one or more types of ways as being available to be allocated to the corresponding processor execution resource.
7 . The processor of claim 6 , wherein the multiple fields comprise a first field which corresponds to one of a core, a thread, or a class of service.
8 . The processor of claim 1 , wherein the first circuitry to identify the cache line comprises the first circuitry to:
determine that the first address corresponds to a first set of a first set-wise partition;
identify an offset between the first set and a first base of the first set-wise partition;
detect an association of the memory access request with a second set-wise partition; and
based on each of the association, the offset, and a second base of the second set-wise partition, identify a second set of the second set-wise partition.
9 . A system comprising:
a processor comprising:
a first one or more registers to provide first information which describes a set-wise partitioning of a cache;
a second one or more registers to provide second information which describes a way-wise partitioning of the cache; and
first circuitry coupled to the first one or more registers and the second one or more registers, the first circuitry to:
receive a memory access request comprising a first address; and
identify a cache line of the cache based on the first address, the set-wise
partitioning, and the way-wise partitioning;
wherein:
the first one or more registers comprise a first plurality of registers which correspond to different ones of multiple set-wise partitions, respectively;
the cache comprises multiple segments which each comprise a same total number of sets; and
for each of the first plurality of registers, the register is to provide a respective first set of bits which is to identify one or more of the multiple segments as belonging to the corresponding set-wise partition; and
a memory coupled to the processor, the memory to store a set of instructions which are to be executed with the processor.
10 . The system of claim 9 , wherein, for each of the first plurality of registers, the register is to further provide a respective second set of bits which is to indicate a base of the corresponding set-wise partition.
11 . The system of claim 9 , wherein, for each set-wise partition of multiple set-wise partitions, the first one or more registers are to identify a respective plurality of addresses as corresponding to the set-wise partition.
12 . The system of claim 9 , wherein the second one or more registers comprise a first register comprising multiple fields which correspond to different processor execution resources, respectively; and
wherein, for each of the multiple fields, the field is to provide a value indicating one or more types of ways as being available to be allocated to the corresponding processor execution resource.
13 . The system of claim 9 , wherein the first circuitry to identify the cache line comprises the first circuitry to:
determine that the first address corresponds to a first set of a first set-wise partition;
identify an offset between the first set and a first base of the first set-wise partition;
detect an association of the memory access request with a second set-wise partition; and
based on each of the association, the offset, and a second base of the second set-wise partition, identify a second set of the second set-wise partition.
14 . A method at a processor, the method comprising:
accessing a first one or more registers to determine a set-wise partitioning of a cache;
accessing a second one or more registers to determine a way-wise partitioning of the cache;
receiving a memory access request comprising a first address; and
identifying a cache line of the cache based on the first address, the set-wise partitioning, and the way-wise partitioning;
wherein:
the first one or more registers comprise a first plurality of registers which correspond to different ones of multiple set-wise partitions, respectively;
the cache comprises multiple segments which each comprise a same total number of sets; and
for each of the first plurality of registers, the register is to provide a respective first set of bits which is to identify one or more of the multiple segments as belonging to the corresponding set-wise partition.
15 . The method of claim 14 , wherein, for each set-wise partition of multiple set-wise partitions, the first one or more registers are to identify a respective plurality of addresses as corresponding to the set-wise partition.
16 . The method of claim 14 , wherein the second one or more registers comprise a first register comprising multiple fields which correspond to different processor execution resources, respectively; and
wherein, for each of the multiple fields, the field is to provide a value indicating one or more types of ways as being available to be allocated to the corresponding processor execution resource.
17 . The method of claim 14 , wherein identifying the cache line comprises:
determining that the first address corresponds to a first set of a first set-wise partition;
identifying an offset between the first set and a first base of the first set-wise partition;
detecting an association of the memory access request with a second set-wise partition; and
based on each of the association, the offset, and a second base of the second set-wise partition, identifying a second set of the second set-wise partition.