[PATCH] formatdomain.html.in: document emulator/vcpu pin delay

Andrea Bolognani abologna at redhat.com
Fri Apr 10 09:36:51 UTC 2020

On Thu, 2020-04-09 at 16:45 -0300, Daniel Henrique Barboza wrote:
> In a guest with only one vcpu, when pinning the emulator in say CPU184
> and the vcpu0 in CPU0 of the host, the user might expect that only
> CPU0 and CPU184 of the host will be used by the guest.
> The reality is that Libvirt takes some time to honor the emulator
> and vcpu pinning, taking care of NUMA constraints first. This will
> result in other CPUs of the host being potentially used by the
> QEMU thread until the emulator/vcpu pinning is done. The user
> then might be confused by the output of 'virsh cpu-stats' in this
> scenario, showing around 200 microseconds of cycles being spent
> in other CPUs.
> Let's document this behavior, which is explained in detail in
> Libvirt commit v5.0.0-199-gf136b83139, in the cputune section
> of formatdomain.html.in.
> Signed-off-by: Daniel Henrique Barboza <danielhb413 at gmail.com>
> ---
>  docs/formatdomain.html.in | 7 +++++++
>  1 file changed, 7 insertions(+)

  Reviewed-by: Andrea Bolognani <abologna at redhat.com>

and pushed.

Andrea Bolognani / Red Hat / Virtualization

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