All types of QOS or what is often called queue priority all types

ios 8.0QOS_CLASS_USER_INTERACTIVE specifies the quality of service of the task to be executed in the queue0x21QOS_CLASS_USER_INITIATED user interaction (you want to complete as soon as possible because the user expects the result0x19QOS_CLASS_DEFAULT, user expectation (do not put too long operation)0x15QOS_CLASS_UTILITY, default (not for programmers, used to reset the use of columns)0x11, utility (time-consuming operation, you can use this option) QOS_CLASS_BACKGROUND0x09, the background QOS_CLASS_UNSPECIFIED0x00, iOS is not specified7.0Previous priority DISPATCH_QUEUE_PRIORITY_HIGH2QOS_CLASS_USER_INITIATED High-priority DISPATCH_QUEUE_PRIORITY_DEFAULT0QOS_CLASS_DEFAULT Default priority DISPATCH_QUEUE_PRIORITY_LOW (2 -QOS_CLASS_UTILITY Low priority DISPATCH_QUEUE_PRIORITY_BACKGROUND INT16_MIN QOS_CLASS_BACKGROUND Background priorityCopy the code

Supplement:

  1. Enumerations after iOS8 can be found inqos.hThere is an official description of each enumeration
  2. The global queue priority category contains only the first five qos categories. QOS_CLASS_UNSPECIFIED is not in the priority of the global queue.
  3. QOS Quality of service