System for automatically and continuously tuning tunable parameters by

Abstract

Tuning mechanisms are provided for tuning tunable parameters of a memory subsystem's cache. A simplified tuning mechanism switches drain mechanisms on and off depending upon the amount of updated buffers present within the cache at a particular time. The drain mechanisms may include a drain-on-read module and a drain-on-write module. In addition, a tuning mechanism automatically and continuously tunes tunable parameters of a storage control processor, by measuring durations of I/O processing events being performed by the storage control processor, and gathering sample values which form sample sets based upon the durations measured. After a first sample set is obtained, a tunable parameter is changed by incrementing or decrementing the parameter by a pre-defined delta value. A second sample set is then obtained after the parameter was changed. Once the second sample set is obtained, the I/O events that were measured to obtain the first sample set are compared to the I/O events that were measured to obtain the second set in order to determine if the mixtures of I/O events are similar. If the mixtures of I/O events of the first sample set are similar to those of the second set, a determination is made as to whether there was an overall decrease in the lengths of durations of I/O processing events measured after the parameter was changed. The parameter change is maintained if it is determined that there was an overall decrease in the lengths of I/O processing event durations measured after the parameter was changed.