On Sat, Jul 01, 2023 at 12:09:09AM +0800, Heng Qi wrote: > On Fri, Jun 30, 2023 at 10:52:25AM -0400, Michael S. Tsirkin wrote: > > On Fri, Jun 30, 2023 at 10:04:08PM +0800, Heng Qi wrote: > > > > > > > > > 在 2023/6/30 下午4:17, Michael S. Tsirkin 写道: > > > > On Fri, Jun 30, 2023 at 02:15:13PM +0800, Heng Qi wrote: > > > > > > > > > > 在 2023/6/30 下午1:59, Michael S. Tsirkin 写道: > > > > > > On Fri, Jun 30, 2023 at 09:55:41AM +0800, Heng Qi wrote: > > > > > > > 在 2023/6/30 上午9:36, Parav Pandit 写道: > > > > > > > > > From: Heng Qi <hen...@linux.alibaba.com> > > > > > > > > > Sent: Thursday, June 29, 2023 8:54 PM > > > > > > > > > > > > > > > > > > On Thu, Jun 29, 2023 at 04:59:28PM +0000, Parav Pandit wrote: > > > > > > > > > > > From: Michael S. Tsirkin <m...@redhat.com> > > > > > > > > > > > Sent: Thursday, June 29, 2023 7:48 AM > > > > > > > > > > > > > struct virtio_net_hash_config reserved is fine. > > > > > > > > > > > > +1. > > > > > > > > > > > > > > > > > > > > > > > > Inner header hash is orthogonal to RSS, and it's fine > > > > > > > > > > > > to have its > > > > > > > > > > > > own structure and commands. > > > > > > > > > > > > There is no need to send additional RSS fields when we > > > > > > > > > > > > configure > > > > > > > > > > > > inner header hash. > > > > > > > > > > > > > > > > > > > > > > > > Thanks. > > > > > > > > > > > Not RSS, hash calculations. It's not critical, but I note > > > > > > > > > > > that > > > > > > > > > > > practically you said you will enable this with symmetric > > > > > > > > > > > hash so it > > > > > > > > > > > makes sense to me to send this in the same command with > > > > > > > > > > > the key. > > > > > > > > > > > > > > > > > > > > > In the v19, we have, > > > > > > > > > > > > > > > > > > > > +\item[VIRTIO_NET_F_HASH_TUNNEL] Requires > > > > > > > > > > VIRTIO_NET_F_CTRL_VQ > > > > > > > > > along with VIRTIO_NET_F_RSS or VIRTIO_NET_F_HASH_REPORT. > > > > > > > > > > So it is done along with rss, so in same struct as rss > > > > > > > > > > config is fine. > > > > > > > > > Do you mean having both virtio_net_rss_config and > > > > > > > > > virtio_net_hash_config > > > > > > > > > have enabled_hash_types? > > > > > > > > > Like this: > > > > > > > > > > > > > > > > > > struct virtio_net_rss_config { > > > > > > > > > le32 hash_types; > > > > > > > > > le16 indirection_table_mask; > > > > > > > > > struct rss_rq_id unclassified_queue; > > > > > > > > > struct rss_rq_id > > > > > > > > > indirection_table[indirection_table_length]; > > > > > > > > > le16 max_tx_vq; > > > > > > > > > u8 hash_key_length; > > > > > > > > > u8 hash_key_data[hash_key_length]; > > > > > > > > > + le32 enabled_tunnel_types; > > > > > > > > > }; > > > > > > > > > > > > > > > > > > struct virtio_net_hash_config { > > > > > > > > > le32 hash_types; > > > > > > > > > - le16 reserved[4]; > > > > > > > > > + le32 enabled_tunnel_types; > > > > > > > > > + le16 reserved[2]; > > > > > > > > > u8 hash_key_length; > > > > > > > > > u8 hash_key_data[hash_key_length]; > > > > > > > > > }; > > > > > > Oh, I forgot that rss and hash had identical structures. > > > > > > And we want to keep that I think. > > > > > > > > > > > > But now it's not clear to me: does the same enabled_tunnel_types > > > > > > apply to both hash calculation and rss? > > > > > Yes. What I'm trying to say is that making the inner header hash and > > > > > RSS/hash calculation clear delimitation will make everything easier. > > > > > The inner header hash just configures enabled_tunnel_types. > > > > > The RSS/hash calculation is configured as before without modification. > > > > > > > > > > > I note we normally have separate configs for hash and rss. > > > > > > So to keep it consistent what should we do? two set commands? > > > > > As I explained above, like outer udp port hash/symmetric toeplitz > > > > > hash, > > > > > these fall under the umbrella of RSS/hash calculation. > > > > Yes but note that symmetric toeplitz hash has to be configured > > > > separately for RSS and for hashing. > > > > > > Yes, this requires a field like \field{mode}, with different values > > > corresponding to different hashing algorithms, such as toeplitz or > > > symmetric > > > toeplitz. > > > The outer port hash belongs to RSS/hash calculation. > > > > So there will be need for more fields. > > Yes, the mode field is outside of RSS/hash, as it should be at a higher > level than RSS/hash. > > > To me this implies extending with struct virtio_net_rss_tunnel_config > > is a better idea since we then have some reserved space to > > put "mode" down the road (in the reserved[6] space below). > > > > No? > > > > > > > > > > > Let's keep the inner header hash simple. > > > > > > > > > > > Or does enabled_tunnel_types apply to both rss and hash? > > > > > Certainly. See: > > > > > > > > > > +\item[VIRTIO_NET_F_HASH_TUNNEL] Requires VIRTIO_NET_F_CTRL_VQ > > > > > along > > > > > with VIRTIO_NET_F_RSS or VIRTIO_NET_F_HASH_REPORT. > > > > > > > > It does not really say that. > > > Oh! I understand now. I think a VIRTIO_NET_CTRL_HASH_TUNNEL_SET command is > > > applied to hash and RSS. Yes. > > > When one wants to configure inner header hash separately, use > > > VIRTIO_NET_CTRL_HASH_TUNNEL_SET command to send enabled_tunnel_types > > > separately. > > > When one wants to configure both inner header hash and RSS/hash, use > > > VIRTIO_NET_CTRL_HASH_TUNNEL_SET together with > > > VIRTIO_NET_CTRL_MQ_RSS_CONFIG/VIRTIO_NET_CTRL_MQ_HASH_CONFIG. > > > The inner header hash is decoupled from RSS/hash, and no extra fields will > > > be sent every configuration. > > > > But why is tunnel so different? Rest of things can be configured > > for hash and for rss separately. > > > > It dawned on me where we were not aligned. Please see more. > > > > > For example I can configure hash for IPv4 and IPv6 but RSS only for > > IPv6. > > Can we have this behavior? > I don't think so, RSS and Hash have the same device configuration, which > is determined by the *last* *device-received* command of the > VIRTIO_NET_CTRL_MQ class. > See the spec: > "If more than one multiqueue mode is negotiated, the resulting device > configuration is defined by the last command sent by the driver."
Oh I was confused. You are right, also this: If the feature VIRTIO_NET_F_RSS was negotiated: \begin{itemize} \item The device uses \field{hash_types} of the virtio_net_rss_config structure as 'Enabled hash types' bitmask. \item The device uses a key as defined in \field{hash_key_data} and \field{hash_key_length} of the virtio_net_rss_config structure (see \ref{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Receive-side scaling (RSS) / Setting RSS parameters}). \end{itemize} If the feature VIRTIO_NET_F_RSS was not negotiated: \begin{itemize} \item The device uses \field{hash_types} of the virtio_net_hash_config structure as 'Enabled hash types' bitmask. \item The device uses a key as defined in \field{hash_key_data} and \field{hash_key_length} of the virtio_net_hash_config structure (see \ref{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Automatic receive steering in multiqueue mode / Hash calculation}). \end{itemize} Sorry about making this noise. I thought I saw a bug. > > But for some reason, if I configure tunnel for GRE it will > > affect both hash and RSS. Why? It seems quite possible to me that I > > was offload for hash for GRE but don't want to use it > > for RSS to avoid RX underrun issues we discussed. > > This makes sense. So the scenario you are referring to should be: > The configuration of RSS/HASH is IPV6, but we have configured > GRE_rfc2784 (both inner and outer headers are IPv4). When the > device receives a GRE_rfc2784 packet, which matches the GRE_rfc2784 > encapsulation type, and then the device need to calculate the hash > based on RSS/Hash, but it turns out that the configured IPv6 of RSS/hash > does not match the inner IPv4. Then nothing happened. ? That would be my understanding too. > If yes, I agree to virtio_net_rss_tunnel_config and > virtio_net_hash_tunnel_config. Or even name them virtio_net_rss_ext_config and virtio_net_hash_ext_config as we expect to use them down the road for other stuff. But since you have corrected my mistake above, a separate SET is ok too. And this is what was reviewed in the last 5 revisions or so. You decide. > > > > > > > > > > > > > > > > > > > > > > We should have reserved more space. We can still do it if you like: > > > > > > > > > > > > struct virtio_net_rss_tunnel_config { > > > > > > le32 enabled_tunnel_types; > > > > > > le16 reserved[6]; > > > > > > struct virtio_net_rss_config hash; > > > > > > }; > > > > > > > > > > > > struct virtio_net_hash_tunnel_config { > > > > > > le32 enabled_tunnel_types; > > > > > > le16 reserved[6]; > > > > > > struct virtio_net_hash_config hash; > > > > > > }; > > > > > > > > > > > > ? > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > If yes, this should have been discussed in v10 [1] before, > > > > > > > > > enabled_tunnel_types > > > > > > > > > in virtio_net_rss_config will follow the variable length > > > > > > > > > field and cause > > > > > > > > > misalignment. > > > > > > > > > > > > > > > > > > If we let the inner header hash reuse the > > > > > > > > > virtio_net_hash_config structure, it > > > > > > > > > can work, but the only disadvantage is that the configuration > > > > > > > > > of the inner > > > > > > > > > header hash and *RSS*(not hash calculations) becomes somewhat > > > > > > > > > coupled. > > > > > > > > > Just imagine: > > > > > > > > > If the driver and the device negotiated > > > > > > > > > VIRTIO_NET_F_HASH_TUNNEL and > > > > > > > > > VIRTIO_NET_F_RSS, but did not negotiate > > > > > > > > > VIRTIO_NET_F_HASH_REPORT, 1. > > > > > > > > > then if we only want to configure the inner header hash (such > > > > > > > > > as > > > > > > > > > enabled_tunnel_types), it is good for us to send > > > > > > > > > virtio_net_hash_config alone; > > > > > > > > > 2. but then if we want to configure the inner header hash and > > > > > > > > > RSS (such as > > > > > > > > > indirection table), we need to send all virtio_net_rss_config > > > > > > > > > and > > > > > > > > > virtio_net_hash_config once, because virtio_net_rss_config > > > > > > > > > now does not carry > > > > > > > > > enabled_tunnel_types due to misalignment. > > > > > > > > > > > > > > > > > > So, I think the following structure will make it clearer to > > > > > > > > > configure inner header > > > > > > > > > hash and RSS/hash calculation. > > > > > > > > > But in any case, if we still propose to reuse > > > > > > > > > virtio_net_hash_config proposal, I > > > > > > > > > am ok, no objection: > > > > > > > > > > > > > > > > > > 1. The supported_tunnel_types are placed in the device config > > > > > > > > > space; > > > > > > > > > > > > > > > > > Yes. I forgot the variable length part. > > > > > > > > The second disadvantage I remember now is one need to resupply > > > > > > > > all the rss hash config parameter and device needs to compare > > > > > > > > and modify for this one field. > > > > > > Or it could be an advantage since one normally wants to configure a > > > > > > symmetric key with this. Further device can just use the new config > > > > > When we want to configure the hash key, he continues to use the > > > > > previous > > > > > rss/hash calculation interface. This is ok. > > > > > > > > > > Thanks. > > > > I don't understand this sentence. My point is simply that > > > > to use the tunnel key has to be symmetric. So two commands > > > > will be required: one to set tunnel types, one to > > > > set the key. > > > > > > Yes, you are right. Then one should be VIRTIO_NET_CTRL_HASH_TUNNEL_SET and > > > the other > > > should be VIRTIO_NET_CTRL_MQ_RSS_CONFIG/VIRTIO_NET_CTRL_MQ_HASH_CONFIG. > > > > > > Thanks. > > > > Well that is still 1 command for tunnels that affects both rss and > > hashing. Why not 2 commands for rss and for hashing? > > > > I think I get you now. > > If the above is correct, then I think we should have the following: > VIRTIO_NET_CTRL_TUNNEL_RSS -> virtio_net_rss_tunnel_config > VIRTIO_NET_CTRL_TUNNEL_HASH -> virtio_net_hash_tunnel_config > > ? > > Thanks! > > > > > > > > > > > > > with no need to check what the old one was. I'd call it a wash. > > > > > > > > > > > > > > Given these two disadvantages, I also prefer independent SET > > > > > > > > command the way you have it. > > > > > > > OK, let's wait for Michael's input again. > > > > > > > > > > > > > > Thanks. > > > > > > This part is not critical to me, but now I understand we need two > > > > > > sets of SET commands. > > > > > > > > > > > > > > > > > > > > > 2. > > > > > > > > > Reserve the following structure: > > > > > > > > > > > > > > > > > > struct virtnet_hash_tunnel { > > > > > > > > > le32 enabled_tunnel_types; > > > > > > > > > }; > > > > > > > > > > > > > > > > > > 3. Reserve the SET command for enabled_tunnel_types and > > > > > > > > > remove the GET > > > > > > > > > command for enabled_tunnel_types. > > > > > > > > > > > > > > > > > > [1] > > > > > > > > > https://lists.oasis-open.org/archives/virtio-dev/202303/msg00317.html > > > > > > > > > > > > > > > > > > Thanks a lot! > > > > > > --------------------------------------------------------------------- > > > > > > To unsubscribe, e-mail: virtio-dev-unsubscr...@lists.oasis-open.org > > > > > > For additional commands, e-mail: > > > > > > virtio-dev-h...@lists.oasis-open.org > > > > > > > > This publicly archived list offers a means to provide input to the > > > > OASIS Virtual I/O Device (VIRTIO) TC. > > > > > > > > In order to verify user consent to the Feedback License terms and > > > > to minimize spam in the list archive, subscription is required > > > > before posting. > > > > > > > > Subscribe: virtio-comment-subscr...@lists.oasis-open.org > > > > Unsubscribe: virtio-comment-unsubscr...@lists.oasis-open.org > > > > List help: virtio-comment-h...@lists.oasis-open.org > > > > List archive: https://lists.oasis-open.org/archives/virtio-comment/ > > > > Feedback License: > > > > https://www.oasis-open.org/who/ipr/feedback_license.pdf > > > > List Guidelines: > > > > https://www.oasis-open.org/policies-guidelines/mailing-lists > > > > Committee: https://www.oasis-open.org/committees/virtio/ > > > > Join OASIS: https://www.oasis-open.org/join/ --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscr...@lists.oasis-open.org For additional commands, e-mail: virtio-dev-h...@lists.oasis-open.org