Method for performing compressed I/O with memory expansion technology

• US 6,944,740 B2
• Filed: 03/27/2002
• Issued: 09/13/2005
• Est. Priority Date: 03/27/2002
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Banikazemi, Mohammad, Poff, Dan E., Abali, Bulent, Schulz, Charles O.
• Primary Examiner(s): Anderson, Matthew D.
• Assistant Examiner(s): THOMAS, SHANE M
• Application Number:
  US10/108,017
• Publication Number:
  US 20030188110A1
• Time in Patent Office: 1,266 Days
• Field of Search: 711170-172, 711/206, 711/173, 711/154, 711/159, 711/207, 711/209, 711/220, 711/221, 707/101, 710/68
• US Class Current: 711/170
• CPC Class Codes: G06F 12/08 in hierarchically structured memory systems, e.g. virtual memory systems
• CPC Class Codes: G06F 12/0802 Addressing of a memory level in which the access to the desired data or data block requires associative addressing means, e.g. caches
• CPC Class Codes: G06F 2212/401 Compressed data

Abstract

A method is provided for manipulating a compressed translation table in a memory expansion technology system. The method comprises swapping contents of an output buffer with contents of a compression buffer, disabling compression for compression translation table entries corresponding to the content swapped to the compression buffer, and packaging entries of a compression translation table corresponding to the contents swapped to the compression buffer, wherein packaged compression translation table entries are accessible to a computer system for addressing the contents swapped to the compression buffer.

Claims

1. A method for manipulating a compressed translation table in a memory expansion technology system comprising:

swapping contents of an output buffer to a compression buffer;

disabling compression for compression translation table entries corresponding to the content swapped to the compression buffer; and

packaging entries of a compression translation table corresponding to the contents swapped to the compression buffer, wherein packaged compression translation table entries are accessible to a computer system for addressing the contents swapped to the compression buffer, and wherein packaging entries of the compression translation table further comprises making a copy of the compression translation table entries, and storing the copy in a buffer.

2. The method of claim 1, wherein swapping further comprises performing a page swap.

3. The method of claim 1, wherein packaging entries of the compression translation table further comprises:

modifying the compression translation table entries; and

generating metadata, wherein the metadata describes contents of a modified compression translation table entry.

4. The method of claim 1, wherein packaging entries of the compression translation table further comprises flushing the compression translation table entries from a cache.

5. The method of claim 1, wherein at least one compression buffer exists in real memory.

6. The method of claim 1, further comprising unpacking entries of the compression translation table, wherein unpacking further comprises:

uncompressing the contents of the compression buffer; and

transferring contents of the compression buffer to a destination buffer.

7. The method of claim 6, wherein uncompressing the contents of the compression buffer comprises:

generating an unpacked compression translation table entries according to metadata describing the compression translation table corresponding to the contents of the compression buffer;

disabling compression for the unpacked compression translation table entries; and

flushing compression translation table entries corresponding to the contents of the compression buffer from a cache.

8. The method of claim 6, further comprising preparing the compression buffer to receive the contents of the compression buffer.

9. The method of claim 8, wherein preparing the compression buffer comprises the step of zeroing out the compression buffer with a page operation.

10. The method of claim 6, wherein transferring the content of the compression buffer comprises one of a page swap and a memory copy.

11. The method of claim 1, wherein disabling compression prevents compression of at least one entry of the compression translation table by hardware and allows packaging of the at least one entry of the compression translation table by software.

12. The method of claim 1, further comprising a memory copy performed prior to the packing for data of the compression buffer, wherein data of the compression buffer is unaligned and the memory copy comprises copying the unaligned data of the compression buffer into a page aligned compression buffer.

13. A program storage device readable by machine, tangibly embodying a program of instructions executable by the machine to perform method steps for manipulating a compressed translation table in a memory expansion technology system, the method steps comprising:

swapping contents of an output buffer to a compression buffer;

disabling compression for compression translation table entries corresponding to the content swapped to the compression buffer; and

packaging entries of a compression translation table corresponding to the contents swapped to the compression buffer, wherein packaged compression translation table entries are accessible to a computer system for addressing the contents swapped to the compression buffer, and wherein packaging entries of the compression translation table further comprises making a copy of the compression translation table entries, and storing the copy in a buffer.

14. The method of claim 13, wherein disabling compression prevents compression of at least one entry of the compression translation table by hardware and allows packaging of the at least one entry of the compression translation table by software.

15. A memory expansion technology system comprising:

a compression buffer reserved for data corresponding to a compression translation table to be packed, wherein a plurality of compression buffers are provided wherein an alignment of data of each of the compression buffers is the same; and

metadata describing the content of the compressed compression translation table after packing.

16. The system of claim 15, wherein compressed entries of the compression translation table comprise a plurality of sector pointers comprising addresses of data in the output buffer.