Browse Prior Art Database

Page Allocation Control

IP.com Disclosure Number: IPCOM000099270D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-14
Document File: 4 page(s) / 97K

Publishing Venue

IBM

Related People

Yamanouchi, N: AUTHOR

Abstract

Disclosed is a method to improve the cache hit of a computer system by controlling the physical page using the activity monitoring circuit. This is effective in the systems with both demand paging a direct-mapped (one way associative), large, physical cache. (Image Omitted)

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Page Allocation Control

       Disclosed is a method to improve the cache hit of a
computer system by controlling the physical page using the activity
monitoring circuit.  This is effective in the systems with both
demand paging a direct-mapped (one way associative), large, physical
cache. 

                            (Image Omitted)

      The outline of the mechanism is such that the physical
allocation algorithm in the demand paging system uses hardware
monitored cache activity data to determine the page allocation to
reduce the cache line aliasing.

      In the following explanation the term "aliased pages" the set
of pages which are mapped to the same range within the direct-mapped
cache.  Cache lines aliased pages potentially cause line aliasing in
the and accesses to these lines may cause cache misses replacements.

      The system consists of 3 components:
 cache activity monitoring circuit (hardware),
 cache activity monitor program (software subsystem), and
 physical page allocation subprograms (software
 components) with
 * new page allocation algorithm, and
 * page move algorithm.
 

                            (Image Omitted)

      These components are laid out in the operating system in Fig.
1.  The activity monitoring hardware is a set of circuitry attached
to the cache management  It consists of event counters which collect
the counts and line replacement counts for each page the cache. Fig.
2 illustrates the counters.  The are cleared when they are read out.

      The activ...