A computer program product comprising a computer readable storage medium, having stored thereon a computer readable program, wherein the computer readable program when executed on a computer causes the computer to:
- receive a request for a subchannel control block (SCB) to perform an operation;
- queue the SCB in one of multiple of timing queues based on an elapsed timeout limit (ETL) of the operation, wherein each operation has associated ETL, and each one of the multiple timing queues has associated ETL for completing an operation;
- determine, without dequeuing the SCB, occurrence of a timeout by computing an elapsed time (ET) and determining that the elapse time is greater then or equal to the ETL, dequeuing the SCB upon the occurrence of the timeout;
- and
- upon completion of the operation, dequeuing the SCB.