** Also affects: linux (Ubuntu)
   Importance: Undecided
       Status: New

** No longer affects: intel

** Also affects: linux (Ubuntu Jammy)
   Importance: Undecided
       Status: New

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https://bugs.launchpad.net/bugs/2058485

Title:
   [ICX] [SPR] [ipc/msg] performance: Mitigate the lock contention with
  percpu counter

Status in linux package in Ubuntu:
  New
Status in linux source package in Jammy:
  New

Bug description:
  This is a public version of https://bugs.launchpad.net/bugs/2034980

  Backport: ipc/msg: mitigate the lock contention with percpu counter
  (merged upstream in 6.1) to jammy

  [Impact]

  The msg_bytes and msg_hdrs atomic counters are frequently updated when
  IPC msg queue is in heavy use, causing heavy cache bounce and
  overhead. Change them to percpu_counter greatly improve the
  performance. Since there is one percpu struct per namespace,
  additional memory cost is minimal. Reading of the count done in msgctl
  call, which is infrequent. So the need to sum up the counts in each
  CPU is infrequent.

  [Fix]
  Backport:
    72d1e611082e ipc/msg: mitigate the lock contention with percpu counter

  [Test Plan]

  I have tested this code.

  [Where problems could occur]

  TODO

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