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Virendra Shambharkar
New User
Joined: 26 Aug 2015
Posts: 55
Location: India
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Hi,
If we reduce the CPU time and run time by the same does the % of MIPS consumed by the job remain the same?
Say a Job runs for 10 hours and take 1 hour of CPU and we reduce the job run time to 5 hours and CPU time to 0.5 hours the MIPS consumed by the Job are the same?
Any information on this will be of great help.
Thanks in advance.
Virendra |
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Robert Sample
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Joined: 06 Jun 2008
Posts: 8696
Location: Dubuque, Iowa, USA
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| Quote: |
| If we reduce the CPU time and run time by the same does the % of MIPS consumed by the job remain the same? |
No, because:
1. MIPS is a measurement of MACHINE capacity and hence cannot be applied to individual jobs.
2. Since MIPS is a measurement of MACHINE capacity, the ONLY way to change the MIPS is to change the machine -- get a larger machine for more, get a smaller machine for less.
3. MIPS is a concept that really makes very little sense these days -- how do you apply million instructions per second (which is what MIPS stands for) to a z13 with 140 processors, some of which are CP, some are zIIP, some are SAP, some are IFL, some are ICF?
For your example, 10 hours is 36,000 seconds and 1 hour of CPU is 3,600 seconds while 5 hours is 18,000 seconds and 1/2 hour of CPU is 1,800 seconds. You have reduced overall CPU consumption of the job by half, but the workload on the system is, most likely, the same since the job still needs 10% of a processor for the elapsed time. |
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Rohit Umarjikar
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steve-myers
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Joined: 30 Nov 2013
Posts: 917
Location: The Universe
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As the link in Mr. Umarjikar's post explains "MIPS" for a single job is sort of meaningless. There are two, and only two, ways to alter this. Neither one is very realistic.- Change to a machine that can execute the instructions in your program at a different rate.
- Change your program to use instructions that execute at a different rate. By definition that will change the program's "MIPS."
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Robert Sample
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Joined: 06 Jun 2008
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Location: Dubuque, Iowa, USA
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Note that 1 MSU = 6 MIPS is specific to a machine type; the ratio varies by machine (IIRC, the z13 is more like 1 MSU = 8 MIPS). Furthermore, Wikipedia has some good comments about the practicality of MSU:
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A million service units (MSU) is a measurement of the amount of processing work a computer can perform in one hour. The term is most commonly associated with IBM mainframes. It reflects how IBM rates the machine in terms of charging capacity. The technical measure of processing power on IBM mainframes, however, are Service Units per second (or SU/sec).
One “service unit” originally related to an actual hardware performance measurement (a specific model’s instruction performance). However, that relationship disappeared many years ago as hardware and software evolved. MSUs are now like other common (but physically imprecise) measurements, such as “cans of coffee” or “tubes of toothpaste.” (Cans and tubes can vary in physical size depending on brand, market, and other factors. Some coffee cans contain 500 grams and others 13 ounces, for example.)
Most mainframe software vendors use a licensing and pricing model in which the customers are charged per MSU consumed (i.e. the number of operations the software has performed) in addition to hardware and software installation costs.[1] Others charge by total MSU system capacity. Thus, while MSU is an artificial construction, it does have a direct financial implication. In fact, software charges are why the MSU measurement exists at all. |
Service units are maintained for CPU, I/O, SRB, and memory (storage) -- so 1 MSU may not relate very closely to CPU usage.
Yes, the term "MIPS" gets used a lot -- and most of the time, the usage is incorrect. The number is easy to understand, even though it has almost no meaning these days. |
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vasanthz
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Joined: 28 Aug 2007
Posts: 1742
Location: Tirupur, India
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| Code: |
| One MSU = 6 Mips (here MSU and Mips represent a consumption speed, not an accumulated consumption). So a job that constantly uses 10 MSU (as displayed by monitors) uses 60 Mips. |
I think this information is too generic and wrong. Every machine has its own soft MSU to MIPS conversion. Cheryl Watson CPU charts are reliable for this information.
And for the original question,
If you are trying to justify your resource saving effort to management. Then just go by saying your effort reduced CPU time & elapsed time and the service units the job consumed. |
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Rohit Umarjikar
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Joined: 21 Sep 2010
Posts: 3051
Location: NYC,USA
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| Quote: |
| I think this information is too generic and wrong. |
On what basis you say it wrong? It concur Robert's statement, This is the stats given by Site support which I cut down to what is needed but has much more, so TS may have one at site, He has to get talking to people. These machines we have for few systems
| Code: |
2964-708 z13 8.3
2964-709 z13 8.3 |
in general.
| Code: |
Model Common Name MIPS/SW MSU
2964-701 z13 8.1
2964-702 z13 8.1
2964-703 z13 8.1
2964-704 z13 8.2
2964-705 z13 8.2
2964-706 z13 8.2
2964-707 z13 8.2
2964-708 z13 8.3
2964-709 z13 8.3
2964-710 z13 8.3
2964-711 z13 8.3
2964-712 z13 8.3
2964-713 z13 8.3
2964-714 z13 8.3
2964-715 z13 8.3
2964-716 z13 8.3
2964-717 z13 8.3
2964-718 z13 8.4
2964-719 z13 8.4
2964-720 z13 8.4
2964-721 z13 8.4
2964-722 z13 8.4
2964-723 z13 8.4
2964-724 z13 8.5
2964-725 z13 8.5
2964-726 z13 8.5
2964-727 z13 8.5
2964-728 z13 8.5
2964-729 z13 8.5
2964-730 z13 8.5
2964-731 z13 8.5
2964-732 z13 8.5
2964-733 z13 8.5
2964-734 z13 8.5
2964-735 z13 8.5
2964-736 z13 8.5
2964-737 z13 8.5
2964-738 z13 8.5
2964-739 z13 8.5
2964-740 z13 8.5
2964-741 z13 8.5
2964-742 z13 8.5
2964-743 z13 8.5
2964-744 z13 8.5
2964-745 z13 8.5
2964-746 z13 8.5
2964-747 z13 8.5
2964-748 z13 8.5
2964-749 z13 8.5
2964-750 z13 8.5
2964-751 z13 8.5
2964-752 z13 8.5
2964-753 z13 8.5
2964-754 z13 8.5
2964-755 z13 8.5
2964-756 z13 8.5
2964-757 z13 8.5
2964-758 z13 8.5
2964-759 z13 8.5
2964-760 z13 8.5
2964-761 z13 8.5
2964-762 z13 8.5
2964-763 z13 8.5
2964-764 z13 8.5
2964-765 z13 8.5
2964-766 z13 8.5
2964-767 z13 8.5
2964-768 z13 8.5
2964-769 z13 8.5
2964-770 z13 8.5
2964-771 z13 8.5
2964-772 z13 8.5
2964-773 z13 8.5
2964-774 z13 8.5
2964-775 z13 8.5
2964-776 z13 8.5
2964-777 z13 8.5
2964-778 z13 8.5
2964-779 z13 8.5
2964-780 z13 8.5
2964-781 z13 8.5
2964-782 z13 8.5
2964-783 z13 8.5
2964-784 z13 8.5
2964-785 z13 8.5
2964-786 z13 8.5
2964-787 z13 8.5
2964-788 z13 8.5
2964-789 z13 8.5
2964-790 z13 8.5
2964-791 z13 8.5
2964-792 z13 8.5
2964-793 z13 8.5
2964-794 z13 8.5
2964-795 z13 8.5
2964-796 z13 8.5
2964-797 z13 8.5
2964-798 z13 8.5
2964-799 z13 8.5
2964-7A0 z13 8.5
2964-7A1 z13 8.5
2964-7A2 z13 8.5
2964-7A3 z13 8.5
2964-7A4 z13 8.5
2964-7A5 z13 8.5
2964-7A6 z13 8.5
2964-7A7 z13 8.5
2964-7A8 z13 8.5
2964-7A9 z13 8.5
2964-7B0 z13 8.5
2964-7B1 z13 8.5
2964-7B2 z13 8.5
2964-7B3 z13 8.5
2964-7B4 z13 8.5
2964-7B5 z13 8.5
2964-7B6 z13 8.5
2964-7B7 z13 8.5
2964-7B8 z13 8.5
2964-7B9 z13 8.5
2964-7C0 z13 8.5
2964-7C1 z13 8.5
2964-7C2 z13 8.5
2964-7C3 z13 8.5
2964-7C4 z13 8.5
2964-7C5 z13 8.5
2964-7C6 z13 8.5
2964-7C7 z13 8.5
2964-7C8 z13 8.5
2964-7C9 z13 8.5
2964-7D0 z13 8.5
2964-7D1 z13 8.5
2964-7D2 z13 8.5
2964-7D3 z13 8.5
2964-7D4 z13 8.5
2964-7D5 z13 8.5
2964-7D6 z13 8.5
2964-7D7 z13 8.5
2964-7D8 z13 8.5
2964-7D9 z13 8.5
2964-7E0 z13 8.5
2964-7E1 z13 8.5 |
| Quote: |
| If you are trying to justify your resource saving effort to management. Then just go by saying your effort reduced CPU time & elapsed time and the service units the job consumed |
What's the harm if TS wants to know MIPS? |
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vasanthz
Global Moderator
Joined: 28 Aug 2007
Posts: 1742
Location: Tirupur, India
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What's the harm if TS wants to know MIPS?
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Job cannot be measured in MIPS. MIPS is the speed of the machine.
I am tired.. I feel like keyboard warrior battling a Trump supporter
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Rohit Umarjikar
Global Moderator
Joined: 21 Sep 2010
Posts: 3051
Location: NYC,USA
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| Quote: |
| Job cannot be measured in MIPS. MIPS is the speed of the machine. |
You don't seems to understand the question asked. MIPS changes per model, that everyone knows by now but TS wants to know the relation between CPU and MIPS how they are related to each other.
This is the calculation at my site and this is directly coming from the same set of people ( Capacity Planner/ Performance Management Group) that you claim to be part of.
The calculation is ( this is just an example):
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Cpu seconds/ (#cpus * 86400) * totalmips
For system XXX(masked)
Cpu seconds / (9*86400) * 12371
If your job ran 60 minutes of cpu (3600 seconds) it is:
(3600 / 777600) * 12371 = 57.27 mips |
I don't think any further discussion is required as TS has what is required. |
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