[pve-devel] proxmox6 : vhost_net experimental_zcopytx=1 bug?

Wolfgang Bumiller w.bumiller at proxmox.com
Wed Aug 21 09:31:04 CEST 2019

On Tue, Aug 20, 2019 at 11:32:57AM +0200, Alexandre DERUMIER wrote:
> Hi,
> Some users have reported vm start timeout on proxmox6
> https://forum.proxmox.com/threads/vm-doesnt-start-proxmox-6-timeout-waiting-on-systemd.56218/
> and for at least 2 of them,
> the vhost_net module option experimental_zcopytx=0 have fixed it.

I do not really see the connection, though... O.o
Could also be an issue with our systemd related code, or with systemd's
scope handling (yet again)...

> It was enable by default since 2012, so maybe regression somewhere. (also redhat disable it by default)
> It seem than in kernel 5.1, the value has been rollback to 0
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v5.2.9&id=9d28094f3cf3b315e784f04ba617de8c8d8978fa 
> Not sure if this patch could be backported in proxmox 5.0 kernel ?

Makes sense IMO. After all it's an upstream decision made due to known issues.

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