Uploaded image for project: 'RHEL'
  1. RHEL
  2. RHEL-42411

qemu-kvm: linux-aio: add support for IO_CMD_FDSYNC command

    • qemu-kvm-9.0.0-5.el9
    • FutureFeature, ZStream
    • rhel-sst-virtualization-storage
    • ssg_virtualization
    • 24
    • None
    • False
    • Hide

      None

      Show
      None
    • None
    • Red Hat Enterprise Linux
    • None
    • Approved Blocker
    • x86_64
    • None

      What were you trying to do that didn't work?

      • While running real-time guest with aio=native without fdsync() support, QEMU creates pthreads, and destroying these pthreads results in TLB flushes. In a real-time guest environment, TLB flushes result in latency spikes.

         

      Please provide the package NVR for which bug is seen:

      $ rpm -q qemu-kvm
      qemu-kvm-8.0.0-16.el9_3.x86_64

      How reproducible:

      100%

      Steps to reproduce

      1.  Set up real-time host and guest environments
      2.  Run oslat/cyclictests inside guest

      Expected results

      • Guest runs without latency spikes

      Actual results

      • Latency spikes are observed.

              rhn-engineering-ppandit Prasad Pandit
              rhn-engineering-ppandit Prasad Pandit
              virt-maint virt-maint
              Junyao Zhao Junyao Zhao
              Votes:
              0 Vote for this issue
              Watchers:
              20 Start watching this issue

                Created:
                Updated:
                Resolved: