Libvirt qemu-system-x86_64 on ppc64le no multi threading

[Kim-Norman Sahm]

Hi Daniel,

attached the versions:

# dpkg -l|grep qemu
ii  ipxe-qemu                              1.0.0+git-20190125.36a4c85-5   all          PXE boot firmware - ROM images for qemu
ii  libvirt-daemon-driver-qemu             6.4.0-2                        ppc64el      Virtualization daemon QEMU connection driver
ii  qemu                                   1:5.0-13                       ppc64el      fast processor emulator, dummy package
ii  qemu-block-extra                       1:5.0-13                       ppc64el      extra block backend modules for qemu-system and qemu-utils
ii  qemu-system-common                     1:5.0-13                       ppc64el      QEMU full system emulation binaries (common files)
ii  qemu-system-data                       1:5.0-13                       all          QEMU full system emulation (data files)
ii  qemu-system-gui:ppc64el                1:5.0-13                       ppc64el      QEMU full system emulation binaries (user interface and audio support)
ii  qemu-system-ppc                        1:5.0-13                       ppc64el      QEMU full system emulation binaries (ppc)
ii  qemu-system-x86                        1:5.0-13                       ppc64el      QEMU full system emulation binaries (x86)
ii  qemu-utils                             1:5.0-13                       ppc64el      QEMU utilities

# dpkg -l|grep libvirt
ii  libvirt-clients                        6.4.0-2                        ppc64el      Programs for the libvirt library
ii  libvirt-daemon                         6.4.0-2                        ppc64el      Virtualization daemon
ii  libvirt-daemon-driver-qemu             6.4.0-2                        ppc64el      Virtualization daemon QEMU connection driver
ii  libvirt-daemon-system                  6.4.0-2                        ppc64el      Libvirt daemon configuration files
ii  libvirt-daemon-system-systemd          6.4.0-2                        ppc64el      Libvirt daemon configuration files (systemd)
ii  libvirt-dbus                           1.4.0-1                        ppc64el      libvirt D-Bus API bindings
ii  libvirt-glib-1.0-0:ppc64el             3.0.0-1                        ppc64el      libvirt GLib and GObject mapping library
ii  libvirt0:ppc64el                       6.4.0-2                        ppc64el      library for interfacing with different virtualization systems
ii  python3-libvirt                        6.1.0-1+b1                     ppc64el      libvirt Python 3 bindings

# qemu-system-x86_64 --version
QEMU emulator version 5.0.0 (Debian 1:5.0-13)
Copyright (c) 2003-2020 Fabrice Bellard and the QEMU Project developers

# libvirtd --version
libvirtd (libvirt) 6.4.0

Regards,
Kim

Am 03.08.20, 16:36 schrieb "Daniel P. Berrangé" <berrange at redhat.com>:

    On Mon, Aug 03, 2020 at 01:45:45PM +0000, Kim-Norman Sahm wrote:
    > hi,
    > 
    > i’m running Debian 10 on POWER9 and would like to spawn x86_64 emulated VMs.
    > The virtual machine is configured to run with 8 vpus but it’s very slow.
    > On the host you can see that the qemu-system-x86_64 process is using just one core!
    > 
    > Ppc64le guests are using multi cores, so its looks like an config problem or software bug with the x86 emulator.

    snip

    > Does anybody knows this problem?

    You've not mentioned what QMEU version or what libvirt version you have.

    Historically though emulation was single threaded. Only with MTTCG has
    it become multi-threaded and thus able to use all cores for vCPUs. THat
    is a few years old now though, so most distros should have MTTCG in some
    form or another if reasonably up2date.

    Regards,
    Daniel
    -- 
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