From: Jakub Kicinski <kuba@kernel•org>
To: davem@davemloft•net
Cc: netdev@vger•kernel.org, edumazet@google•com, pabeni@redhat•com,
andrew+netdev@lunn•ch, horms@kernel•org, donald.hunter@gmail•com,
sdf@fomichev•me, almasrymina@google•com, dw@davidwei•uk,
asml.silence@gmail•com, ap420073@gmail•com, jdamato@fastly•com,
dtatulea@nvidia•com, michael.chan@broadcom•com,
Jakub Kicinski <kuba@kernel•org>
Subject: [RFC net-next 01/22] docs: ethtool: document that rx_buf_len must control payload lengths
Date: Mon, 21 Apr 2025 15:28:06 -0700 [thread overview]
Message-ID: <20250421222827.283737-2-kuba@kernel.org> (raw)
In-Reply-To: <20250421222827.283737-1-kuba@kernel.org>
Document the semantics of the rx_buf_len ethtool ring param.
Clarify its meaning in case of HDS, where driver may have
two separate buffer pools.
The various zero-copy TCP Rx schemes we have suffer from memory
management overhead. Specifically applications aren't too impressed
with the number of 4kB buffers they have to juggle. Zero-copy
TCP makes most sense with larger memory transfers so using
16kB or 32kB buffers (with the help of HW-GRO) feels more
natural.
Signed-off-by: Jakub Kicinski <kuba@kernel•org>
---
Documentation/networking/ethtool-netlink.rst | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst
index b6e9af4d0f1b..eaa9c17a3cb1 100644
--- a/Documentation/networking/ethtool-netlink.rst
+++ b/Documentation/networking/ethtool-netlink.rst
@@ -957,7 +957,6 @@ Kernel checks that requested ring sizes do not exceed limits reported by
driver. Driver may impose additional constraints and may not support all
attributes.
-
``ETHTOOL_A_RINGS_CQE_SIZE`` specifies the completion queue event size.
Completion queue events (CQE) are the events posted by NIC to indicate the
completion status of a packet when the packet is sent (like send success or
@@ -971,6 +970,11 @@ completion queue size can be adjusted in the driver if CQE size is modified.
header / data split feature. If a received packet size is larger than this
threshold value, header and data will be split.
+``ETHTOOL_A_RINGS_RX_BUF_LEN`` controls the size of the buffer chunks driver
+uses to receive packets. If the device uses different memory polls for headers
+and payload this setting may control the size of the header buffers but must
+control the size of the payload buffers.
+
CHANNELS_GET
============
--
2.49.0
next prev parent reply other threads:[~2025-04-21 22:28 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-21 22:28 [RFC net-next 00/22] net: per-queue rx-buf-len configuration Jakub Kicinski
2025-04-21 22:28 ` Jakub Kicinski [this message]
2025-04-22 16:19 ` [RFC net-next 01/22] docs: ethtool: document that rx_buf_len must control payload lengths David Wei
2025-04-22 19:48 ` Joe Damato
2025-04-23 20:08 ` Mina Almasry
2025-04-25 22:50 ` Jakub Kicinski
2025-04-25 23:20 ` Joe Damato
2025-04-21 22:28 ` [RFC net-next 02/22] net: ethtool: report max value for rx-buf-len Jakub Kicinski
2025-04-21 22:28 ` [RFC net-next 03/22] net: use zero value to restore rx_buf_len to default Jakub Kicinski
2025-04-21 22:28 ` [RFC net-next 04/22] net: clarify the meaning of netdev_config members Jakub Kicinski
2025-04-22 19:57 ` Joe Damato
2025-04-21 22:28 ` [RFC net-next 05/22] net: add rx_buf_len to netdev config Jakub Kicinski
2025-04-21 22:28 ` [RFC net-next 06/22] eth: bnxt: read the page size from the adapter struct Jakub Kicinski
2025-04-23 20:35 ` Mina Almasry
2025-04-25 22:51 ` Jakub Kicinski
2025-04-21 22:28 ` [RFC net-next 07/22] eth: bnxt: set page pool page order based on rx_page_size Jakub Kicinski
2025-04-22 15:32 ` Stanislav Fomichev
2025-04-22 15:52 ` Jakub Kicinski
2025-04-22 17:27 ` Stanislav Fomichev
2025-04-21 22:28 ` [RFC net-next 08/22] eth: bnxt: support setting size of agg buffers via ethtool Jakub Kicinski
2025-04-23 21:00 ` Mina Almasry
2025-04-25 22:58 ` Jakub Kicinski
2025-04-21 22:28 ` [RFC net-next 09/22] net: move netdev_config manipulation to dedicated helpers Jakub Kicinski
2025-04-21 22:28 ` [RFC net-next 10/22] net: reduce indent of struct netdev_queue_mgmt_ops members Jakub Kicinski
2025-04-23 21:04 ` Mina Almasry
2025-04-21 22:28 ` [RFC net-next 11/22] net: allocate per-queue config structs and pass them thru the queue API Jakub Kicinski
2025-04-23 21:17 ` Mina Almasry
2025-04-25 23:24 ` Jakub Kicinski
2025-04-21 22:28 ` [RFC net-next 12/22] net: pass extack to netdev_rx_queue_restart() Jakub Kicinski
2025-04-21 22:28 ` [RFC net-next 13/22] net: add queue config validation callback Jakub Kicinski
2025-04-22 15:49 ` Stanislav Fomichev
2025-04-22 20:16 ` Joe Damato
2025-04-21 22:28 ` [RFC net-next 14/22] eth: bnxt: always set the queue mgmt ops Jakub Kicinski
2025-04-22 15:50 ` Stanislav Fomichev
2025-04-22 20:18 ` Joe Damato
2025-04-21 22:28 ` [RFC net-next 15/22] eth: bnxt: store the rx buf size per queue Jakub Kicinski
2025-04-21 22:28 ` [RFC net-next 16/22] eth: bnxt: adjust the fill level of agg queues with larger buffers Jakub Kicinski
2025-04-22 16:13 ` Stanislav Fomichev
2025-04-21 22:28 ` [RFC net-next 17/22] netdev: add support for setting rx-buf-len per queue Jakub Kicinski
2025-04-22 16:15 ` Stanislav Fomichev
2025-04-25 23:41 ` Jakub Kicinski
2025-04-21 22:28 ` [RFC net-next 18/22] net: wipe the setting of deactived queues Jakub Kicinski
2025-04-22 16:21 ` Stanislav Fomichev
2025-04-25 23:42 ` Jakub Kicinski
2025-04-21 22:28 ` [RFC net-next 19/22] eth: bnxt: use queue op config validate Jakub Kicinski
2025-04-23 10:00 ` Dragos Tatulea
2025-04-23 13:46 ` Jakub Kicinski
2025-04-23 14:24 ` Dragos Tatulea
2025-04-23 15:33 ` Jakub Kicinski
2025-06-12 11:56 ` Dragos Tatulea
2025-06-12 14:10 ` Jakub Kicinski
2025-06-12 15:52 ` Dragos Tatulea
2025-06-12 22:30 ` Jakub Kicinski
2025-06-13 19:02 ` Dragos Tatulea
2025-06-13 23:16 ` Jakub Kicinski
2025-06-17 12:36 ` Dragos Tatulea
2025-04-21 22:28 ` [RFC net-next 20/22] eth: bnxt: support per queue configuration of rx-buf-len Jakub Kicinski
2025-04-21 22:28 ` [RFC net-next 21/22] selftests: drv-net: add helper/wrapper for bpftrace Jakub Kicinski
2025-04-22 16:36 ` Stanislav Fomichev
2025-04-22 16:39 ` Stanislav Fomichev
2025-06-25 12:23 ` Breno Leitao
2025-04-21 22:28 ` [RFC net-next 22/22] selftests: drv-net: add test for rx-buf-len Jakub Kicinski
2025-04-22 17:06 ` Stanislav Fomichev
2025-04-25 23:52 ` Jakub Kicinski
2025-04-23 20:02 ` [RFC net-next 00/22] net: per-queue rx-buf-len configuration Mina Almasry
2025-04-25 23:55 ` Jakub Kicinski
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