[Qemu-devel] [Bug 1441781] Re: qemuProcessSetEmulatorAffinity() called before emulator process actually running

[Chris Friesen]

** Description changed:

- In qemuProcessStart() the code looks like this:
+ When running on a 24-CPU host and using vCPU and emulator pinning I've
+ seen cases where the specified emulator pinning isn't applied as
+ expected.
  
-     VIR_DEBUG("Setting cgroup for emulator (if required)");
-     if (qemuSetupCgroupForEmulator(vm) < 0)
-         goto cleanup;
- 
-     VIR_DEBUG("Setting affinity of emulator threads");
-     if (qemuProcessSetEmulatorAffinity(vm) < 0)
-         goto cleanup;
- 
-     VIR_DEBUG("Waiting for monitor to show up");
-     if (qemuProcessWaitForMonitor(driver, vm, asyncJob, priv->qemuCaps, pos) 
< 0)
-         goto cleanup;
- 
- 
- When running on a 24-CPU host and using vCPU and emulator pinning I've seen 
cases where the specified emulator pinning isn't applied as expected.
- 
- The issue appears to be due to libvirt racing with qemu.  Moving the
- qemuProcessSetEmulatorAffinity() call to after
- qemuProcessWaitForMonitor() returns seems to fix the problem.
- 
- Also, I suspect that qemuSetupCgroupForEmulator() should probably be
- moved as well.
+ It appears the bug was introduced by 411cea6 which moved both
+ qemuSetupCgroupForEmulator() and qemuProcessSetEmulatorAffinity() up
+ before the call to qemuProcessWaitForMonitor().  Reverting this commit
+ makes the problem go away.

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https://bugs.launchpad.net/bugs/1441781

Title:
  qemuProcessSetEmulatorAffinity() called before emulator process
  actually running

Status in QEMU:
  New

Bug description:
  When running on a 24-CPU host and using vCPU and emulator pinning I've
  seen cases where the specified emulator pinning isn't applied as
  expected.

  It appears the bug was introduced by 411cea6 which moved both
  qemuSetupCgroupForEmulator() and qemuProcessSetEmulatorAffinity() up
  before the call to qemuProcessWaitForMonitor().  Reverting this commit
  makes the problem go away.

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