PVU
Okay, so I need to figure out what PVU stands for. Let me start by breaking down the acronym. PVU... P could be Power, V might be Volume, and U could be Utilization. But I'm not entirely sure. Maybe it's related to servers or computing resources? I remember hearing terms like PVU in the context of licensing for software like IBM products.
Wait, IBM uses PVU (Processing Virtual Units) for licensing their software. Each PVU represents a unit of processing power, right? So when you install software like DB2 or WebSphere, the number of PVUs depends on the number of processors and the type of hardware. But how exactly do they calculate PVUs? I think it's based on the number of processors and the capacity of each processor. Maybe there's a formula involved.
Let me check. If a server has multiple processors, each processor's capacity is considered. For example, if a processor has a capacity of 100%, then each core might count as a certain number of PVUs. But I'm not sure if it's per core or per physical processor. Also, some processors have different speeds or capabilities, so maybe they use a normalized value.
I recall that IBM defines a PVU as a unit of measure for workload processing power. The total PVU for a system is calculated by multiplying the number of processors by the capacity of each processor. The capacity is often a percentage, but IBM might have specific values for different processor models. For example, a processor with a capacity of 100% would contribute 1 PVU per core, but maybe some processors have higher capacities.
Wait, no, maybe it's the other way around. If a processor has a capacity of 100%, then each core is 1 PVU. If a processor is underclocked or has lower capacity, each core might contribute less. But how do they determine the capacity? Is it based on the processor's speed compared to a base model? For example, a processor that's twice as fast as the base might have a capacity of 200%, so each core would count as 2 PVUs.
Also, there's something about active core ratio. Maybe if a core isn't being used, it doesn't count towards the PVU. So the calculation might involve the number of active cores multiplied by their capacity. But I'm not entirely clear on that.
Another angle: PVU licensing is used to determine how many licenses you need based on the workload. So if your system has a total PVU count, you have to ensure that your licensed PVUs cover that. For example, if your system has 1000 PVUs, you need to have purchased enough licenses for 1000 PVUs.
But how does this apply in real scenarios? Let's say a server has 4 physical processors, each with 8 cores, and each core has a capacity of 100%. Then the total PVU would be 4 * 8 * 1 = 32 PVUs. But if some processors have higher capacity, like 150%, then it would be 4 * 8 * 1.5 = 48 PVUs. Wait, but maybe it's per physical processor, not per core. That's a key point.
I think IBM's PVU calculation is based on physical processors, not cores. So each physical processor has a certain capacity, and you multiply the number of processors by their capacity. For example, if a server has 4 physical processors, each with a capacity of 100%, then total PVU is 4 * 1 = 4 PVUs. But if a processor has a capacity of 50%, then it's 4 * 0.5 = 2 PVUs.
But how do they determine the capacity of each processor? IBM probably provides a list of processor models and their corresponding capacities. For example, a processor model A might have a capacity of 100%, model B 150%, etc. So when you install the software, you look up each processor's model, get the capacity, sum them up, and that's your total PVU count.
Wait, but some sources say that PVU is calculated per core. That's conflicting. Let me verify. According to IBM's documentation, PVU is calculated based on the number of physical processors and their capacity. However, some newer processors might have multiple cores, but the capacity is assigned per physical processor, not per core. So even if a processor has 8 cores, if its capacity is 100%, it counts as 1 PVU for that processor. But if the capacity is higher, say 200%, then it's 2 PVUs per processor.
But I'm still confused. Let me look up an example. Suppose a server has two physical processors, each with a capacity of 100%. Then total PVU is 2. If another server has four physical processors, each with 50% capacity, total PVU is 4 * 0.5 = 2. So both servers would require the same number of licenses.
However, if a processor has a higher capacity, like 150%, then each such processor would count as 1.5 PVUs. So two processors at 150% would be 3 PVUs.
But how does this apply to multi-core processors? If a processor has 8 cores but is assigned a capacity of 100%, does each core count as 1/8th of a PVU? Or is the entire processor counted as 1 PVU regardless of cores?
I think the key here is that PVU is based on the physical processor's capacity, not the number of cores. So even if a processor has multiple cores, the entire processor is considered as one unit with a certain capacity. Therefore, the number of cores doesn't directly affect the PVU count unless the capacity is adjusted per core, which I don't think is the case.
But wait, maybe IBM has changed their approach. Some sources mention that for certain processors, especially with more cores, the capacity might be calculated differently. For example, a processor with 16 cores might have a higher base capacity. But I'm not sure.
Another point: IBM provides a PVU capacity matrix that lists each processor model and its corresponding PVU capacity. Customers use this matrix to calculate their total PVU count. So the formula would be Total PVU = Sum of (Number of processors * PVU capacity per processor).
For example, if a server has 4 processors: 2 of model A (capacity 100%) and 2 of model B (capacity 150%), then total PVU = (2 * 1) + (2 * 1.5) = 2 + 3 = 5 PVUs.
This makes sense. So the main factors are the number of physical processors and their individual capacities as per IBM's matrix. Cores don't directly factor in unless the capacity is specified per core, which I don't think is standard.
But wait, there's also the concept of active core ratio. Maybe if not all cores are active, the capacity is adjusted. For example, if a processor has 8 cores but only 4 are active, does that reduce the capacity? Or is the capacity fixed based on the processor model regardless of core usage?
I think the capacity is based on the processor model, not the actual usage. So even if some cores are idle, the full capacity of the processor is counted. However, IBM might have introduced a way to measure active cores, but I'm not certain.
In summary, PVU stands for Processing Virtual Units, used by IBM to measure the workload processing power for licensing their software. The calculation involves multiplying the number of physical processors by their respective capacities as defined in IBM's PVU matrix. Cores don't directly affect the count unless the capacity is specified per core, which is not typical. The total PVU count determines how many licenses are needed based on the workload.
PVU (Processing Virtual Units) is a licensing metric used by IBM to measure the workload processing power of a system for software products like DB2, WebSphere, and others. Here's a structured breakdown:
Key Points:
Definition:
PVU represents a unit of processing power, normalized across different processor models. It helps determine the number of licenses required based on the system's computational capacity.
Calculation:
Formula:
[
\text{Total PVU} = \sum (\text{Number of Processors} \times \text{PVU Capacity per Processor})
]
Capacity per Processor: Defined by IBM in a PVU matrix, where each processor model has a specific capacity (e.g., 100%, 150%). This capacity is based on the processor's speed relative to a base model.
https://www.18122.com/url/usdt/usdt3289.jpg
Processor Consideration:
Physical Processors, Not Cores: PVU counts are based on physical processors, not individual cores. For example, a 16-core processor with a capacity of 100% counts as 1 PVU, regardless of core count.
Matrix Lookup: Customers refer to IBM's PVU capacity matrix to find the capacity for each processor model in their environment.
Example:
A server with 4 physical processors:
2 processors of Model A (capacity 100%): (2 \times 1 = 2) PVU
2 processors of Model B (capacity 150%): (2 \times 1.5 = 3) PVU
Total PVU: (2 + 3 = 5) PVU.
Licensing:
The total PVU count determines the number of licenses needed. For instance, if a software product requires 10 PVU licenses, a system with 10 PVU would need exactly 10 licenses.
Active Core Ratio:
Historically, PVU was based on physical processors only. Modern approaches may consider active cores, but IBM's standard practice remains tied to physical processors and predefined capacities.
Practical Implications:
Right-Size Licensing: Ensures customers purchase sufficient licenses without overpaying.
Hardware Planning: Helps choose processors with appropriate capacities to align with license counts.
Documentation: IBM provides detailed PVU matrices and guidelines for accurate calculations.
Summary:
PVU is a critical metric for IBM software licensing, calculated by summing the product of physical processors and their predefined capacities. Cores do not directly affect PVU unless specified in newer guidelines, which remain processor-centric. Proper adherence ensures compliance and cost-efficiency.
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