Purging without write-back of cache lines containing spent data
First Claim
1. A system for providing to a processor copies of data in a memory having memory sections, said system comprising a cache, said cache having plural cache lines of plural cache-line sections each for containing data, each of said cache-line sections representing at most one respective memory section at any given time, said cache further including means for indicating for each of said cache-line sections whether or not it contains valid data having spent status, said cache including a cache manager for writing back to said memory a cache line containing modified valid data not having spent status and for purging a cache line having modified valid data having spent status without writing said cache line back to said memory.
3 Assignments
0 Petitions
Accused Products
Abstract
The present invention provides a system with a cache that indicates which, if any, of its sections contain data having spent status. The invention also provides a method for identifying cache sections containing data having spent status and then purging without writing back to main memory a cache line having at least one section containing data having spent status. The invention further provides a program that specifies a cache-line section containing data that is to acquire “spent” status. “Spent” data, herein, is useless modified or unmodified data that was formerly at least potentially useful data when it was written to a cache. “Purging” encompasses both invalidating and overwriting.
-
Citations
36 Claims
- 1. A system for providing to a processor copies of data in a memory having memory sections, said system comprising a cache, said cache having plural cache lines of plural cache-line sections each for containing data, each of said cache-line sections representing at most one respective memory section at any given time, said cache further including means for indicating for each of said cache-line sections whether or not it contains valid data having spent status, said cache including a cache manager for writing back to said memory a cache line containing modified valid data not having spent status and for purging a cache line having modified valid data having spent status without writing said cache line back to said memory.
-
7. A method comprising:
-
executing a program of instructions that assigns spent status to data stored in cache-line sections; writing back to memory a cache line containing modified valid data not having spent status; and purging without writing back to said memory a cache line having at least one section containing modified valid data having spent status. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
-
- 18. Computer readable media comprising a program of instructions that, when executed, changes the contents of status fields of a write-back cache to indicate whether or not a cache line containing modified valid data is to be written back to memory before being purged.
-
26. A computer system comprising:
-
a cache with plural cache lines of plural cache-line sections each for containing data, said cache further including means for indicating for each of said cache lines how many of its sections contain valid data having spent status, each of said cache-line sections representing at most one respective memory section at any given time; and a cache manager that purges without writing back to memory a cache line when all of its cache-line sections contain data having spent status and that writes back prior to purging a cache line containing modified valid unspent data. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35)
-
-
36. A system for providing to a processor copies of data in a cache having plural cache lines for containing data, said cache further including means for indicating for each of said cache lines whether or not it contains valid data having spent status.
Specification