netdev - Re: [PATCH 2/2] virtio-net: reduce the CPU consumption of dim worker

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CACGkMEu8or7+fw3+vX_PY3Qsrm7zVSf6TS9SiE20NpOsz-or6g@mail.gmail.com>
Date: Mon, 25 Mar 2024 13:57:40 +0800
From: Jason Wang <jasowang@...hat.com>
To: Heng Qi <hengqi@...ux.alibaba.com>
Cc: netdev@...r.kernel.org, virtualization@...ts.linux.dev, 
	"Michael S. Tsirkin" <mst@...hat.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, 
	Eric Dumazet <edumazet@...gle.com>, "David S. Miller" <davem@...emloft.net>, 
	Xuan Zhuo <xuanzhuo@...ux.alibaba.com>
Subject: Re: [PATCH 2/2] virtio-net: reduce the CPU consumption of dim worker

On Mon, Mar 25, 2024 at 10:21 AM Heng Qi <hengqi@...ux.alibaba.com> wrote:
>
>
>
> 在 2024/3/22 下午1:19, Jason Wang 写道:
> > On Thu, Mar 21, 2024 at 7:46 PM Heng Qi <hengqi@...ux.alibaba.com> wrote:
> >> Currently, ctrlq processes commands in a synchronous manner,
> >> which increases the delay of dim commands when configuring
> >> multi-queue VMs, which in turn causes the CPU utilization to
> >> increase and interferes with the performance of dim.
> >>
> >> Therefore we asynchronously process ctlq's dim commands.
> >>
> >> Signed-off-by: Heng Qi <hengqi@...ux.alibaba.com>
> > I may miss some previous discussions.
> >
> > But at least the changelog needs to explain why you don't use interrupt.
>
> Will add, but reply here first.
>
> When upgrading the driver's ctrlq to use interrupt, problems may occur
> with some existing devices.
> For example, when existing devices are replaced with new drivers, they
> may not work.
> Or, if the guest OS supported by the new device is replaced by an old
> downstream OS product, it will not be usable.
>
> Although, ctrlq has the same capabilities as IOq in the virtio spec,
> this does have historical baggage.

I don't think the upstream Linux drivers need to workaround buggy
devices. Or it is a good excuse to block configure interrupts.

And I remember you told us your device doesn't have such an issue.

Thanks

>
> Thanks,
> Heng
>
> >
> > Thanks
>