netdev - Re: [PATCH v2 net-next] virtio: Fix affinity for #VCPUs != #queue pairs

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] [day] [month] [year] [list]

Date:   Wed, 15 Feb 2017 14:13:55 -0800
From:   Benjamin Serebrin <serebrin@...gle.com>
To:     "Michael S. Tsirkin" <mst@...hat.com>
Cc:     Willem de Bruijn <willemdebruijn.kernel@...il.com>,
        Christian Borntraeger <borntraeger@...ibm.com>,
        Network Development <netdev@...r.kernel.org>,
        Jason Wang <jasowang@...hat.com>,
        David Miller <davem@...emloft.net>,
        Willem de Bruijn <willemb@...gle.com>,
        Venkatesh Srinivas <venkateshs@...gle.com>,
        "Jon Olson (Google Drive)" <jonolson@...gle.com>,
        Rick Jones <rick.jones2@....com>,
        James Mattson <jmattson@...gle.com>,
        linux-s390 <linux-s390@...r.kernel.org>,
        "linux-arch@...r.kernel.org" <linux-arch@...r.kernel.org>
Subject: Re: [PATCH v2 net-next] virtio: Fix affinity for #VCPUs != #queue pairs

On Wed, Feb 15, 2017 at 1:49 PM, Michael S. Tsirkin <mst@...hat.com> wrote:

> The logic is simple really. With #VCPUs == #queues we can reasonably
> assume this box is mostly doing networking so we can set affinity
> the way we like. With VCPUs > queues clearly VM is doing more stuff
> so we need a userspace policy to take that into account,
> we don't know ourselves what is the right thing to do.
>
> Arguably for #VCPUs == #queues we are not always doing the right thing
> either but I see this as an argument to move more smarts
> into core kernel not for adding more dumb heuristics in the driver.

Thanks for all the feedback, Michael.  We'll drop this patch and move
to user mode.

Thanks,
Ben