ERROR: COS out of bounds for task <64957>

intel / intel-cmt-cat

User space software for Intel(R) Resource Director Technology

http://www.intel.com/content/www/us/en/architecture-and-technology/resource-director-technology.html

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ERROR: COS out of bounds for task <64957> #222

Closed kazi-m22 closed 2 years ago

kazi-m22 commented 2 years ago

I am trying to switch the assigned COS for application based on PID using OS interface. When I try to assign COS number, it switches if the COS number is from 0-7. If I put any COS number grater than 7, it shows:

ERROR: COS out of bounds for task <64957>

From pqos -I -sV I have found following: INFO: L3 CAT details: CDP support=1, CDP on=0, #COS=16, #ways=11, ways contention bit-mask 0x600

What I understand here, there should be 16 COS available

mdcornu commented 2 years ago

When using the OS interface, the number of COS is limited to what is common to all supported allocation technologies. On your system, most likely MBA supports 8 COS, so L3CAT will be limited to 8 also.

See documentation here: https://www.kernel.org/doc/html/latest/x86/resctrl.html

kazi-m22 commented 2 years ago

Thanks!