QoS management in the L2 cache

A level two (L2) cache controller configured to:

• receive a plurality of memory requests from two or more processors;
• monitor a first number of outstanding memory requests issued by a first processor;
• monitor a second number of outstanding memory requests issued by a second processor;
• assign a first quality of service (QoS) parameter to a given memory request from the first processor responsive to determining the first number is less than a first threshold;
• assign a second QoS parameter to the given memory request from the first processor responsive to determining the first number is greater than the first threshold;
• assign a first QoS parameter to a given memory request from the second processor responsive to determining the second number is greater than a second threshold;
• and
• assign a second QoS parameter to the given memory request from the second processor responsive to determining the second number is greater than the second threshold, wherein the second QoS parameter is of a lower priority than the first QoS parameter.

A method comprising:

• monitoring a number of outstanding memory requests;
• generating a new memory request, wherein the new memory request is generated by a processor;
• assigning the new memory request a first quality of service (QoS) parameter if the number of outstanding memory requests is below a threshold;
• assigning the new memory request a second QoS parameter if the number of outstanding memory requests is above the threshold;
• and
• subsequent to generating the new memory request, the method comprises:
• looking up an indicator in a configuration register, wherein the indicator is stored in a configuration register entry corresponding to the memory request type of the new memory request;
• assigning a predetermined QoS parameter for the new memory request if the indicator is a first value;
• and
• assigning a QoS parameter to the new memory request based on a comparison of the number of outstanding memory requests to the threshold if the indicator is a second value.

A method comprising:

• receiving a memory request at a level 2 (L2) cache controller;
• comparing a count of outstanding memory requests to a threshold;
• responsive to the count being less than the threshold, assigning a first priority level to the memory request;
• and
• responsive to the count being greater than the threshold, assigning a second priority level to the memory request, wherein the second priority level is lower than the first priority level.