From: "Michael S. Tsirkin" <mst@redhat.com>
To: Yuri Benditovich <yuri.benditovich@daynix.com>
Cc: Akihiko Odaki <akihiko.odaki@daynix.com>,
Jason Wang <jasowang@redhat.com>,
qemu-devel@nongnu.org, Andrew Melnychenko <andrew@daynix.com>
Subject: Re: [PATCH v6 11/21] virtio-net: Return an error when vhost cannot enable RSS
Date: Thu, 2 Nov 2023 09:18:35 -0400 [thread overview]
Message-ID: <20231102091717-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <CAOEp5OdEudOFXuitG2NSBfuCQiwFJ72rYZsyvLFRfKR4kQvTDg@mail.gmail.com>
On Thu, Nov 02, 2023 at 02:00:46PM +0200, Yuri Benditovich wrote:
>
>
> On Thu, Nov 2, 2023 at 1:26 PM Michael S. Tsirkin <mst@redhat.com> wrote:
>
> On Thu, Nov 02, 2023 at 12:20:39PM +0200, Yuri Benditovich wrote:
> >
> >
> > On Thu, Nov 2, 2023 at 11:33 AM Michael S. Tsirkin <mst@redhat.com>
> wrote:
> >
> > On Thu, Nov 02, 2023 at 11:09:27AM +0200, Yuri Benditovich wrote:
> > > Probably we mix two different patches in this discussion.
> > > Focusing on the patch in the e-mail header:
> > >
> > > IMO it is not acceptable to fail QEMU run for one feature that we
> can't
> > make
> > > active when we silently drop all other features in such a case.
> >
> > If the feature is off by default then it seems more reasonable
> > and silent masking can be seen as a bug.
> > Most virtio features are on by default this is why it's
> > reasonable to mask them.
> >
> >
> >
> > If we are talking about RSS: setting it initially off is the development
> time
> > decision.
> > When it will be completely stable there is no reason to keep it off by
> default,
> > so this is more a question of time and of a readiness of libvirt.
>
> Well when we flip the default we'll need compat machinery for sure ;)
>
>
> Of course, on the flip or default we'll need to keep compatibility to earlier
> machine types.
> But, because in the perspective it makes sense to make the RSS is on by
> default, I do not think we need _now_ to make qemu fail to start if the ebpf
> can't be loaded.
>
Generally if user asks for something and we can't do it, we must fail.
If we can't apply a default we need a better default.
qemu has a bug in that it can't generally distinguish between default set
automatically and same default given on command line.
--
MST
next prev parent reply other threads:[~2023-11-02 13:19 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-30 5:12 [PATCH v6 00/21] virtio-net RSS/hash report fixes and improvements Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 01/21] tap: Remove tap_probe_vnet_hdr_len() Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 02/21] tap: Remove qemu_using_vnet_hdr() Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 03/21] net: Move virtio-net header length assertion Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 04/21] net: Remove receive_raw() Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 05/21] tap: Remove tap_receive() Akihiko Odaki
2023-10-30 18:52 ` Zhang, Chen
2023-10-31 4:57 ` Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 06/21] net: Remove flag propagation Akihiko Odaki
2023-11-10 7:35 ` Pavel Dovgalyuk
2023-11-11 14:27 ` Akihiko Odaki
2023-11-13 8:14 ` Pavel Dovgalyuk
2023-10-30 5:12 ` [PATCH v6 07/21] tap: Shrink zeroed virtio-net header Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 08/21] virtio-net: Copy header only when necessary Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 09/21] virtio-net: Disable RSS on reset Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 10/21] virtio-net: Unify the logic to update NIC state for RSS Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 11/21] virtio-net: Return an error when vhost cannot enable RSS Akihiko Odaki
2023-10-30 12:14 ` Yuri Benditovich
2023-10-30 12:21 ` Akihiko Odaki
2023-10-30 12:51 ` Yuri Benditovich
2023-10-30 13:14 ` Akihiko Odaki
2023-11-01 4:19 ` Jason Wang
2023-11-01 4:50 ` Akihiko Odaki
2023-11-01 6:38 ` Michael S. Tsirkin
2023-11-01 8:35 ` Akihiko Odaki
2023-11-01 9:09 ` Michael S. Tsirkin
2023-11-01 9:15 ` Akihiko Odaki
2023-11-02 9:09 ` Yuri Benditovich
2023-11-02 9:33 ` Michael S. Tsirkin
2023-11-02 10:20 ` Yuri Benditovich
2023-11-02 11:26 ` Michael S. Tsirkin
2023-11-02 12:00 ` Yuri Benditovich
2023-11-02 13:18 ` Michael S. Tsirkin [this message]
2023-11-02 14:56 ` Akihiko Odaki
2023-11-03 9:35 ` Yuri Benditovich
2023-11-03 9:55 ` Akihiko Odaki
2023-11-03 13:14 ` Yuri Benditovich
2023-11-11 15:28 ` Akihiko Odaki
2023-11-13 11:44 ` Yuri Benditovich
2023-11-13 12:44 ` Akihiko Odaki
2023-11-13 17:26 ` Yuri Benditovich
2023-11-14 7:03 ` Akihiko Odaki
2023-11-14 22:09 ` Yuri Benditovich
2023-11-15 6:09 ` Akihiko Odaki
2023-11-16 5:14 ` Jason Wang
2023-10-30 5:12 ` [PATCH v6 12/21] virtio-net: Enable software RSS Akihiko Odaki
2023-10-30 12:42 ` Yuri Benditovich
2023-10-30 5:12 ` [PATCH v6 13/21] virtio-net: Always set populate_hash Akihiko Odaki
2023-10-30 19:02 ` Zhang, Chen
2023-10-31 4:47 ` Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 14/21] virtio-net: Do not write hashes to peer buffer Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 15/21] virtio-net: Do not clear VIRTIO_NET_F_HASH_REPORT Akihiko Odaki
2023-11-03 13:26 ` Yuri Benditovich
2023-10-30 5:12 ` [PATCH v6 16/21] ebpf: Fix RSS error handling Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 17/21] ebpf: Use standard section name Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 18/21] ebpf: Simplify error handling Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 19/21] ebpf: Return 0 when configuration fails Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 20/21] ebpf: Refactor tun_rss_steering_prog() Akihiko Odaki
2023-10-30 5:12 ` [PATCH v6 21/21] ebpf: Add a separate target for skeleton Akihiko Odaki
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