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Oracle® X5 Series Servers Administration Guide

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Updated: September 2017
 
 

Understanding Elastic Computing

Elastic computing refers to the ability to maximize performance by selectively activating and deactivating processor cores, which causes a subsequent decrease or increase in maximum frequency of the remaining active cores. This allows you to set the optimal balance between core count and maximum frequency for a given workload.

Each core supports one or two virtual processors, depending on whether hyperthreading is enabled or not. Virtual processors support threads; increasing the number of active cores increases the number of virtual processors, which allows the application to support more threads.

Deactivating all of the virtual processors associated with a core deactivates the core.


Note -  For Linux operating systems, virtual processors are called logical processors.

Some workloads are not able to take advantage of having many threads, but instead benefit from having fewer threads running at higher frequencies.

Before elastic computing, you had to order your server with a processor designed to have the optimal core count and frequency for your specific workload. Elastic computing gives you the ability to configure a single server dynamically to meet the needs of many types of workloads.

You can activate or deactivate cores using the Solaris or Oracle Linux OS, or the BIOS Setup Utility.

  • Using the OS commands, you can activate and deactivate virtual processors while the application is running, causing the desired change in the number of cores available to optimize application performance. . This is the preferred method; however it requires that you have the Oracle Linux or Oracle Solaris operating systems. Using this method you can adjust performance dynamically, as often as necessary.

  • If you have any other supported operating system, you can activate or deactivate cores using the BIOS Setup Utility. While you can change the settings whenever you wish, this method requires rebooting the server.


Note -  If hyperthreading is enabled, to deactivate a core, you must deactivate both virtual processors associated with that core.

Cores and Maximum Frequency

The following table shows the relationship between active cores (on a given socket) and maximum frequency.


Note -  The Intel Xeon E7-8895v3 processor has a core frequency of 2.6 GHz, but has a maximum frequency of 3.0 to 3.5 GHz. Changing the number of active cores changes the maximum frequency, not the core frequency.
Number of Active Cores
Maximum Frequency (GHz)
1 to 6
3.5
7 to 8
3.4
9 to 12
3.3
13 to 14
3.2
15 to 18
3.0