US 2006/0080509 A1 · Method and apparatus to purge remote node cache lines to support hot node replace in a computing system

Abstract

An apparatus and method is disclosed for flushing a cache in a computing system. In a multinode computing system a cache in a first node may contain modified data in an address space of a second node. The cache in the first node must be purged prior to shutting down the first node. The computing system uses a random class replacement scheme for the cache. A cache flush routine sets a cache flush mode in a class replace select mechanism, overriding the random class replacement scheme. With the random class replacement scheme overridden, a minimum number of fetches will flush all the cache lines in the cache, each fetch loading the cache with a cache line not already in the cache. No additional delay penalty is incurred in a critical path through which fetches and stores to the cache must pass.

Claims18

Dependent claims

A computer system comprising:

a processor;
an associative cache coupled to the processor, the cache further comprising:
a cache replace mechanism having a random pattern generator used in a random replace scheme;
an address mechanism;
a cache select mechanism;
and a cache array;
a main memory coupled to the processor;
wherein, by switching the cache replacement mechanism from using the random replace scheme to using a deterministic scheme, the cache can be flushed to the main memory by making a minimum number of fetches to the cache, and without addition of logic blocks to the address mechanism or the cache select mechanism beyond a number of logic blocks required to read and write the cache.

5 more elements

Dependencies are inferred from the claim text.

Method and apparatus to purge remote node cache lines to support hot node replace in a computing system

Life of this patent

Method and apparatus to purge remote node cache lines to support hot node replace in a computing system

Life of this patent

Abstract

Claims18