What are the "Unwire Memory" and "Wire Memory" statistics in Instruments?

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Created Jul ’20

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When I run an Instruments "Metal" Profile, I see measurements for "Driver Processing."

Sub-statistics are "Unwire Memory" and "Wire Memory."

What are these activities?

The in-app help documentation does not explain these, nor other Metal related profiling.

The docs just cover things like memory / disk / network / energy stats.

Version 12.0 (12A8158a)

Answered by Graphics and Games Engineer in 619311022

Hi, these are driver activities ensuring that the physical backing memory exist for GPU resources so they cannot be paged out (Wire Memory), or can be paged out (Unwire Memory). So that they can be used in the GPU commands, or paged out for other things when needed.

See IOKit fundamentals: https://developer.apple.com/library/archive/documentation/DeviceDrivers/Conceptual/IOKitFundamentals/DataMgmt/DataMgmt.html

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Graphics and Games Engineer OP

Apple

Jul ’20

Accepted Answer

Hi, these are driver activities ensuring that the physical backing memory exist for GPU resources so they cannot be paged out (Wire Memory), or can be paged out (Unwire Memory). So that they can be used in the GPU commands, or paged out for other things when needed.

See IOKit fundamentals: https://developer.apple.com/library/archive/documentation/DeviceDrivers/Conceptual/IOKitFundamentals/DataMgmt/DataMgmt.html

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