Why PVU is important to TM1 performance

Depending on your license agreement, when you buy TM1, it is likely that you buy a limit number of PVUs. Knowing how many CPU your TM1 server requires will help you to adjust the number of PVUs you really need.

A Processor Value Unit is a unit of measure to quantify the capability/speed of the processor on your TM1 server. IBM uses the PVU as a common licensing metric used accross IBM technology. 

The number of PVU per core depends on the processor technology (defined by Processor Vendor, Brand, Type and Processor Model Number) on which the customer is running the software.

if you want to know exactly how much PVU your server has, you can use the IBM PVU calculator. In the example below the server has a Total PVU = 560:

Having lots of PVU enable you to increase the number of CPU your TM1 server can use to do the calculation. To enable TM1 to use multiple processor cores, you have to update the MTQ parameter in the tm1s.cfg. MTQ will significantly increase the speed at which TM1 can perform calculations and queries by allowing queries to split into multiple processing threads.

It is important to notice that an increase in cores doesn’t have a pro rata speed impact. This is attributed to the fact that the non-stargate operations associated with displaying a view still require a fixed amount of time, you can see below that after 32 you do not win lots of time:

Increasing the number of processors on your TM1 server typically has a positive impact on TM1 performance…. However it isn’t necessarily a silver bullet and needs to be considered in the context of:

• Model complexity
• Number of users
• Load processing times
• Other applications on the server

You should analyse how much CPU your server requires. Maybe you’re paying for more PVU than you need. 

Pulse can help you to know how many CPUs your application is using. In the Pulse live monitor at the top left you can see the CPU % your application currently uses:

or you can use the server performance report to see all maximum CPU events during a timeframe:

Knowing how many CPU your application is using will help you to adapt the number of PVU you need.

For more information about PVU, you can check the IBM PVU FAQ.