From: Stanislav Fomichev <stfomichev@gmail.com>
To: Pavel Begunkov <asml.silence@gmail.com>
Cc: Jakub Kicinski <kuba@kernel.org>,
netdev@vger.kernel.org, io-uring@vger.kernel.org,
Eric Dumazet <edumazet@google.com>,
Willem de Bruijn <willemb@google.com>,
Paolo Abeni <pabeni@redhat.com>,
andrew+netdev@lunn.ch, horms@kernel.org, davem@davemloft.net,
sdf@fomichev.me, almasrymina@google.com, dw@davidwei.uk,
michael.chan@broadcom.com, dtatulea@nvidia.com,
ap420073@gmail.com
Subject: Re: [RFC v1 00/22] Large rx buffer support for zcrx
Date: Wed, 30 Jul 2025 08:50:28 -0700 [thread overview]
Message-ID: <aIo_RMVBBWOJ7anV@mini-arch> (raw)
In-Reply-To: <46fabfb5-ee39-43a2-986e-30df2e4d13ab@gmail.com>
On 07/30, Pavel Begunkov wrote:
> On 7/29/25 17:33, Stanislav Fomichev wrote:
> > On 07/28, Pavel Begunkov wrote:
> > > On 7/28/25 23:06, Stanislav Fomichev wrote:
> > > > On 07/28, Pavel Begunkov wrote:
> > > > > On 7/28/25 21:21, Stanislav Fomichev wrote:
> > > > > > On 07/28, Pavel Begunkov wrote:
> > > > > > > On 7/28/25 18:13, Stanislav Fomichev wrote:
> > > > > ...>>> Supporting big buffers is the right direction, but I have the same
> > > > > > > > feedback:
> > > > > > >
> > > > > > > Let me actually check the feedback for the queue config RFC...
> > > > > > >
> > > > > > > it would be nice to fit a cohesive story for the devmem as well.
> > > > > > >
> > > > > > > Only the last patch is zcrx specific, the rest is agnostic,
> > > > > > > devmem can absolutely reuse that. I don't think there are any
> > > > > > > issues wiring up devmem?
> > > > > >
> > > > > > Right, but the patch number 2 exposes per-queue rx-buf-len which
> > > > > > I'm not sure is the right fit for devmem, see below. If all you
> > > > >
> > > > > I guess you're talking about uapi setting it, because as an
> > > > > internal per queue parameter IMHO it does make sense for devmem.
> > > > >
> > > > > > care is exposing it via io_uring, maybe don't expose it from netlink for
> > > > >
> > > > > Sure, I can remove the set operation.
> > > > >
> > > > > > now? Although I'm not sure I understand why you're also passing
> > > > > > this per-queue value via io_uring. Can you not inherit it from the
> > > > > > queue config?
> > > > >
> > > > > It's not a great option. It complicates user space with netlink.
> > > > > And there are convenience configuration features in the future
> > > > > that requires io_uring to parse memory first. E.g. instead of
> > > > > user specifying a particular size, it can say "choose the largest
> > > > > length under 32K that the backing memory allows".
> > > >
> > > > Don't you already need a bunch of netlink to setup rss and flow
> > >
> > > Could be needed, but there are cases where configuration and
> > > virtual queue selection is done outside the program. I'll need
> > > to ask which option we currently use.
> >
> > If the setup is done outside, you can also setup rx-buf-len outside, no?
>
> You can't do it without assuming the memory layout, and that's
> the application's role to allocate buffers. Not to mention that
> often the app won't know about all specifics either and it'd be
> resolved on zcrx registration.
I think, fundamentally, we need to distinguish:
1. chunk size of the memory pool (page pool order, niov size)
2. chunk size of the rx queue entries (this is what this series calls
rx-buf-len), mostly influenced by MTU?
For devmem (and same for iou?), we want an option to derive (2) from (1):
page pools with larger chunks need to generate larger rx entries.
next prev parent reply other threads:[~2025-07-30 15:50 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-28 11:04 [RFC v1 00/22] Large rx buffer support for zcrx Pavel Begunkov
2025-07-28 11:04 ` [RFC v1 01/22] docs: ethtool: document that rx_buf_len must control payload lengths Pavel Begunkov
2025-07-28 18:11 ` Mina Almasry
2025-07-28 21:36 ` Mina Almasry
2025-08-01 23:13 ` Jakub Kicinski
2025-07-28 11:04 ` [RFC v1 02/22] net: ethtool: report max value for rx-buf-len Pavel Begunkov
2025-07-29 5:00 ` Subbaraya Sundeep
2025-07-28 11:04 ` [RFC v1 03/22] net: use zero value to restore rx_buf_len to default Pavel Begunkov
2025-07-29 5:03 ` Subbaraya Sundeep
2025-07-28 11:04 ` [RFC v1 04/22] net: clarify the meaning of netdev_config members Pavel Begunkov
2025-07-28 21:44 ` Mina Almasry
2025-08-01 23:14 ` Jakub Kicinski
2025-07-28 11:04 ` [RFC v1 05/22] net: add rx_buf_len to netdev config Pavel Begunkov
2025-07-28 21:50 ` Mina Almasry
2025-08-01 23:18 ` Jakub Kicinski
2025-07-28 11:04 ` [RFC v1 06/22] eth: bnxt: read the page size from the adapter struct Pavel Begunkov
2025-07-28 11:04 ` [RFC v1 07/22] eth: bnxt: set page pool page order based on rx_page_size Pavel Begunkov
2025-07-28 11:04 ` [RFC v1 08/22] eth: bnxt: support setting size of agg buffers via ethtool Pavel Begunkov
2025-07-28 11:04 ` [RFC v1 09/22] net: move netdev_config manipulation to dedicated helpers Pavel Begunkov
2025-07-28 11:04 ` [RFC v1 10/22] net: reduce indent of struct netdev_queue_mgmt_ops members Pavel Begunkov
2025-07-28 11:04 ` [RFC v1 11/22] net: allocate per-queue config structs and pass them thru the queue API Pavel Begunkov
2025-07-28 11:04 ` [RFC v1 12/22] net: pass extack to netdev_rx_queue_restart() Pavel Begunkov
2025-07-28 11:04 ` [RFC v1 13/22] net: add queue config validation callback Pavel Begunkov
2025-07-28 22:26 ` Mina Almasry
2025-07-28 11:04 ` [RFC v1 14/22] eth: bnxt: always set the queue mgmt ops Pavel Begunkov
2025-07-28 11:04 ` [RFC v1 15/22] eth: bnxt: store the rx buf size per queue Pavel Begunkov
2025-07-28 22:33 ` Mina Almasry
2025-08-01 23:20 ` Jakub Kicinski
2025-07-28 11:04 ` [RFC v1 16/22] eth: bnxt: adjust the fill level of agg queues with larger buffers Pavel Begunkov
2025-07-28 11:04 ` [RFC v1 17/22] netdev: add support for setting rx-buf-len per queue Pavel Begunkov
2025-07-28 23:10 ` Mina Almasry
2025-08-01 23:37 ` Jakub Kicinski
2025-07-28 11:04 ` [RFC v1 18/22] net: wipe the setting of deactived queues Pavel Begunkov
2025-07-28 11:04 ` [RFC v1 19/22] eth: bnxt: use queue op config validate Pavel Begunkov
2025-07-28 11:04 ` [RFC v1 20/22] eth: bnxt: support per queue configuration of rx-buf-len Pavel Begunkov
2025-07-28 11:04 ` [RFC v1 21/22] net: parametrise mp open with a queue config Pavel Begunkov
2025-08-02 0:10 ` Jakub Kicinski
2025-08-04 12:50 ` Pavel Begunkov
2025-08-05 22:43 ` Jakub Kicinski
2025-08-06 0:05 ` Jakub Kicinski
2025-08-06 16:48 ` Mina Almasry
2025-08-06 18:11 ` Jakub Kicinski
2025-08-06 18:30 ` Mina Almasry
2025-08-06 22:05 ` Jakub Kicinski
2025-07-28 11:04 ` [RFC v1 22/22] io_uring/zcrx: implement large rx buffer support Pavel Begunkov
2025-07-28 17:13 ` [RFC v1 00/22] Large rx buffer support for zcrx Stanislav Fomichev
2025-07-28 18:18 ` Pavel Begunkov
2025-07-28 20:21 ` Stanislav Fomichev
2025-07-28 21:28 ` Pavel Begunkov
2025-07-28 22:06 ` Stanislav Fomichev
2025-07-28 22:44 ` Pavel Begunkov
2025-07-29 16:33 ` Stanislav Fomichev
2025-07-30 14:16 ` Pavel Begunkov
2025-07-30 15:50 ` Stanislav Fomichev [this message]
2025-07-31 19:34 ` Mina Almasry
2025-07-31 19:57 ` Pavel Begunkov
2025-07-31 20:05 ` Mina Almasry
2025-08-01 9:48 ` Pavel Begunkov
2025-08-01 9:58 ` Pavel Begunkov
2025-07-28 23:22 ` Mina Almasry
2025-07-29 16:41 ` Stanislav Fomichev
2025-07-29 17:01 ` Mina Almasry
2025-07-28 18:54 ` Mina Almasry
2025-07-28 19:42 ` Pavel Begunkov
2025-07-28 20:23 ` Mina Almasry
2025-07-28 20:57 ` Pavel Begunkov
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