101results about How to "Avoid hunger" patented technology

A system and method are provided for dynamically determining the priority of requests for access to a resource taking into account changes in the access needs of a requesting agent over time. A requesting agent selects a priority level from a plurality of priority selections to include with a priority request to an arbiter. Work requests requiring the access to a resource may be stored in a work request queue. The priority level may be dynamic. The dynamic priority level enables the agent to sequentially increase or decrease the priority level of a priority request when threshold values representing the number of work requests in the work request queue are reached. The threshold values which cause the priority level to be increased may be higher than the threshold values which cause the priority level to be decreased to provide hysteresis. The dynamic priority level may, alternatively, enable the agent to start a timer for timing a pending priority request for a predetermined time period. The priority level of the priority request is increased if the priority request has not been granted before the timer expires.

The present disclosure is a system and method for improved RAID rebuilds under host IO conditions, that greatly improves rebuild times and prevents host IO starvation. A queue in a drive that is part of the RAID is used to store rebuild and host IO requests, with rebuild IOs issued to the head of the drive queue. Rebuild requests in the drive are delayed by a delay time. This delay ensures there is no unintended side effect of this invention that may result in host IO starvation for the RAID system. Delay is computed as a heuristic function from a plurality of variables, such as disk head response times, time allotted for rebuild, number of rebuild threads, drive behavior, rebuild IO profile, host IO profile including workload and locality, and a timeline of sequenced events, which in one preferred embodiment cycles every 70 seconds.