Method to reduce reactivation time of cloud based services

A system for reducing reactivation time of services comprising

• a page faults analyzer that examines physical addresses of page faults during processing of a service after the service has been inactive;
• a decision tree analyzer that creates a prefetch decision tree from the physical addresses from page fault data in at least one prefetch group, wherein the prefetch decision tree includes a plurality of edges providing a probability that a physical page address will be touched during a service request;
• a page comparator that following a reactivated service request compares physical page addresses from an page table for said service to determine whether said physical pages addresses are in resident memory as prefetched page addresses in accordance with the prefetch decision tree, wherein the physical page addresses in the page table that are not included in prefetched page addresses are paged in;
• a page in insertor that inserts the paged out page physical addresses into memory through bulk restore;
• a page table updater for inserting said paged out physical addresses into said initial page table to provide an updated page table;
• and
• a process executor to provide said service said updated page table.

A computer readable storage medium comprising a computer readable program for reducing reactivation time of services, wherein the computer readable program when executed on a computer causes the computer to perform the steps of:

• examining page faults that occur during processing of a service after the service has been inactive, wherein said examining includes analyzing physical addresses that caused said page faults;
• formulating a prefetch decision tree from the physical addresses from page fault data in at least one prefetch group, wherein the prefetch decision tree includes a Plurality of edges providing a probability that a page will be touched during a service request;
• comparing whether physical addresses for pages from an initial page table for said service following a reactivated service request are in resident memory as prefetched addresses for pages in accordance with the prefetch decision tree, wherein physical addresses for pages in the page table that are not included in said prefetched pages are paged in;
• inserting previously paged out pages in an in parameter/out parameter vector for bulk restore;
• and
• executing a process to provide said service using said physical addresses for pages in the page table.