RESMIL value

The residency time (also called the RESMIL value) is the amount of time that the RSA-message spends in each system in the ring in addition to the time needed to processes the RSA-message.

Residency time value (RESMIL) and Residency time value (RESMIL) describe how to set an initial value when you set up your complex. Use this information in tuning your complex. Setting the initial RESMIL value correctly is your best technique for tuning the complex.

Establishing a response time objective is one way to select a value for RESMIL. (See Measuring response time for one way to measure actual response time.) To establish a response time objective, determine what response time is acceptable or desirable, then set the RESMIL value to meet that objective.

Choose a low response time objective (10 milliseconds or lower) if all of the systems in the complex are 3090 processors or if any one of the following conditions is true:

Your installation has chosen to convert catalog reserve SYSIGGV2.
Your installation has batch jobs that issue many global resource requests and that must complete in a fixed time.

Once you have set a response time objective, you next translate that objective into a RESMIL value, depending on the number of systems in the ring. Table 1 and Table 2 can help you with this process. The RESMIL values shown are based on the formulas shown earlier in Average response time, with the following assumptions:

The RSA-message contains only one request.
The transmission time is one millisecond.
There is no contention time for the requested resource.

The RESMIL values shown have been rounded down to the nearest integer.

As described earlier, there are many factors (such as data transmission rate, RSA-message size, and global resource request rate) that affect the actual response time. Thus, setting a particular RESMIL value does not guarantee meeting the corresponding response time objective. You can, however, use the RESMIL value in the table as a starting point. Use the values in Table 1 if you use ring acceleration; use the values in Table 2 if you do not.

Table 1. RESMIL Values with Ring Acceleration — ACCELSYS(2)
Response Time Objective (Milliseconds)	2-System Ring	3-System Ring	4-System Ring	5-System Ring
10	3	2	2	1
20	8	6	5	4
30	13	10	8	7
40	18	14	12	10
50	23	18	15	13

Table 2. RESMIL Values without Ring Acceleration
Response Time Objective (Milliseconds)	2-System Ring	3-System Ring	4-System Ring	5-System Ring
10	2	1	0	0
20	5	3	2	1
30	9	5	4	3
40	12	7	5	4
50	15	10	7	5