Accelerating software rejuvenation by communicating rejuvenation events

1. A computer readable medium embodying instructions executable by a processor to perform a method for triggering a software rejuvenation system or method, the method comprising:

receiving a request for resources at a node;

determining an estimated response time to the request for resources;

determining that the estimated response time is greater than a first threshold; and

triggering the software rejuvenation system or method at the node, the triggering including broadcasting an alert upon determining one of,

a number of estimated response times greater than the first threshold is greater than or equal to a dynamic second threshold, and

a prior alert is received from another node.

2. The computer readable medium of claim 1 , wherein the software rejuvenation is triggered by the prior alert only if the prior alert is a first alert.

3. The computer readable medium of claim 1 , wherein determining the estimated response time comprises:

sampling a plurality of response times; and

determining an average response time, wherein the average response time is used as the estimated response time.

4. The computer readable medium of claim 1 , wherein the first threshold varies according to a number of estimated response times greater than the first threshold, and the dynamic second threshold is determined each time the first threshold is varied.

5. The computer readable medium of claim 4 , further comprising increasing the first threshold with the number of response times greater than the first threshold.

6. The computer readable medium of claim 1 , wherein the dynamic second threshold is a positive integer.

7. A computer readable medium embodying instructions executable by a processor to perform a method for triggering a software rejuvenation system or method, the method comprising:

receiving a request for resources at a node;

determining a response time to the request for resources;

increasing a number of response times greater than a first threshold upon determining that the response time is greater than the first threshold;

decreasing the number of response times greater than the first threshold upon determining that the response time is less than the first threshold; and

triggering the software rejuvenation system or method at the node upon determining one of,

the number of response times greater than the first threshold is greater than or equal to a dynamic second threshold, and

a prior alert is received from another node.

8. The computer readable medium of claim 7 , wherein the software rejuvenation is triggered by the prior alert only if the prior alert is a first alert.

9. The computer readable medium of claim 7 , further comprising:

increasing the first threshold by a number of standard deviations upon determining the number of response times greater than the first threshold is greater than D, wherein the first threshold can be increased K standard deviations, and wherein K and D are the same or different positive integers, and the second threshold is K multiplied by D; and

re-determining the dynamic second threshold upon increasing the first threshold.

10. The computer readable medium of claim 7 , further comprising:

decreasing the first threshold by a number of standard deviations upon determining the number of response times greater than the first threshold is less than D, wherein the first threshold can be decreased K standard deviations, and wherein K and D are the same or different positive integers, and the second threshold is K multiplied by D; and

re-determining the dynamic second threshold upon decreasing the first threshold.

11. The computer readable medium of claim 7 , wherein the request for resources is generated by a client.

12. The computer readable medium of claim 7 , wherein the request for resources is generated by a load injector.

13. The computer readable medium of claim 7 , further comprising initializing with the number of response times greater than the first threshold at zero, the first threshold set at a lowest level, and the dynamic second threshold at a highest level.

14. A computer readable medium embodying instructions executable by a processor to perform a method for distinguishing between a burst of requests and a decrease in performance of a software product, the method comprising comprising:

receiving a plurality of requests for resources;

comparing each of the plurality of requests to a first variable threshold; varying the first variable threshold to distinguish between a burst of requests and a decrease in performance of a software product for handling the plurality of requests;

varying a second variable threshold upon varying the first variable threshold; and

triggering a software rejuvenation system or method upon determining one of,

a number of response times greater than the first variable threshold at a predetermined highest level is greater than or equal to the second variable threshold, and

a prior alert is received from another node.

15. The computer readable medium of claim 14 , wherein the software rejuvenation is triggered by the prior alert only if the prior alert is a first alert.

16. The computer readable medium of claim 14 , further comprising:

determining a source of each request causing the software rejuvenation to be triggered; and

determining a common source of a predetermined number of the requests causing the software rejuvenation to be triggered, wherein the software rejuvenation system or method is triggered at a computer node nearest to the common source from among a plurality of computer nodes.

17. The computer readable medium of claim 14 , further comprising initializing with the number of response times greater than the first variable threshold at zero, the first variable threshold set at a lowest level, and the second variable threshold at a highest level.