Re: [PATCH net-next] net: ethtool: add COALESCE_RX_CQE_FRAMES/NSECS parameters
From: Tariq Toukan <hidden>
Date: 2026-02-24 12:01:42
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linux-doc, linux-hyperv, lkml
On 22/02/2026 23:23, Haiyang Zhang wrote:
quoted hunk ↗ jump to hunk
From: Haiyang Zhang <haiyangz@microsoft.com> Add two parameters for drivers supporting Rx CQE Coalescing. ETHTOOL_A_COALESCE_RX_CQE_FRAMES: Maximum number of frames that can be coalesced into a CQE. ETHTOOL_A_COALESCE_RX_CQE_NSECS: Time out value in nanoseconds after the first packet arrival in a coalesced CQE to be sent. Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> --- Documentation/netlink/specs/ethtool.yaml | 8 ++++++++ Documentation/networking/ethtool-netlink.rst | 10 ++++++++++ include/linux/ethtool.h | 6 +++++- include/uapi/linux/ethtool_netlink_generated.h | 2 ++ net/ethtool/coalesce.c | 14 +++++++++++++- 5 files changed, 38 insertions(+), 2 deletions(-)diff --git a/Documentation/netlink/specs/ethtool.yaml b/Documentation/netlink/specs/ethtool.yaml index 0a2d2343f79a..951d98f6bb12 100644 --- a/Documentation/netlink/specs/ethtool.yaml +++ b/Documentation/netlink/specs/ethtool.yaml@@ -861,6 +861,12 @@ attribute-sets: name: tx-profile type: nest nested-attributes: profile + - + name: rx-cqe-frames + type: u32 + - + name: rx-cqe-nsecs + type: u32 - name: pause-stat@@ -2244,6 +2250,8 @@ operations: - tx-aggr-time-usecs - rx-profile - tx-profile + - rx-cqe-frames + - rx-cqe-nsecs dump: *coalesce-get-op - name: coalesce-setdiff --git a/Documentation/networking/ethtool-netlink.rst b/Documentation/networking/ethtool-netlink.rst index af56c304cef4..a3e78b69fd07 100644 --- a/Documentation/networking/ethtool-netlink.rst +++ b/Documentation/networking/ethtool-netlink.rst@@ -1072,6 +1072,8 @@ Kernel response contents: ``ETHTOOL_A_COALESCE_TX_AGGR_TIME_USECS`` u32 time (us), aggr, Tx ``ETHTOOL_A_COALESCE_RX_PROFILE`` nested profile of DIM, Rx ``ETHTOOL_A_COALESCE_TX_PROFILE`` nested profile of DIM, Tx + ``ETHTOOL_A_COALESCE_RX_CQE_FRAMES`` u32 max packets, Rx CQE + ``ETHTOOL_A_COALESCE_RX_CQE_NSECS`` u32 delay (ns), Rx CQE =========================================== ====== ======================= Attributes are only included in reply if their value is not zero or the@@ -1105,6 +1107,12 @@ well with frequent small-sized URBs transmissions. to DIM parameters, see `Generic Network Dynamic Interrupt Moderation (Net DIM) <https://www.kernel.org/doc/Documentation/networking/net_dim.rst>`_. +Rx CQE coalescing allows multiple received packets to be coalesced into a single +Completion Queue Entry (CQE). ``ETHTOOL_A_COALESCE_RX_CQE_FRAMES`` describes the +maximum number of frames that can be coalesced into a CQE. +``ETHTOOL_A_COALESCE_RX_CQE_NSECS`` describes max time in nanoseconds after the +first packet arrival in a coalesced CQE to be sent. +
I am trying to understand how generic this feature/API is. Can you please elaborate on the feature you want to configure here? A single CQE to describe several packets? What is the price? What per-packet information/hw offloads do you lose in the process? For comparison, in mlx5 we have RX CQE compression, which can be applied on multiple near-identical completions that share/match several fields. Still, there is a per-packet mini-cqe with distinctive per-packet fields like csum.
quoted hunk ↗ jump to hunk
COALESCE_SET ============@@ -1143,6 +1151,8 @@ Request contents: ``ETHTOOL_A_COALESCE_TX_AGGR_TIME_USECS`` u32 time (us), aggr, Tx ``ETHTOOL_A_COALESCE_RX_PROFILE`` nested profile of DIM, Rx ``ETHTOOL_A_COALESCE_TX_PROFILE`` nested profile of DIM, Tx + ``ETHTOOL_A_COALESCE_RX_CQE_FRAMES`` u32 max packets, Rx CQE + ``ETHTOOL_A_COALESCE_RX_CQE_NSECS`` u32 delay (ns), Rx CQE =========================================== ====== ======================= Request is rejected if it attributes declared as unsupported by driver (i.e.diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h index 798abec67a1b..25ccd2d5d4dc 100644 --- a/include/linux/ethtool.h +++ b/include/linux/ethtool.h@@ -332,6 +332,8 @@ struct kernel_ethtool_coalesce { u32 tx_aggr_max_bytes; u32 tx_aggr_max_frames; u32 tx_aggr_time_usecs; + u32 rx_cqe_frames; + u32 rx_cqe_nsecs; }; /**@@ -380,7 +382,9 @@ bool ethtool_convert_link_mode_to_legacy_u32(u32 *legacy_u32, #define ETHTOOL_COALESCE_TX_AGGR_TIME_USECS BIT(26) #define ETHTOOL_COALESCE_RX_PROFILE BIT(27) #define ETHTOOL_COALESCE_TX_PROFILE BIT(28) -#define ETHTOOL_COALESCE_ALL_PARAMS GENMASK(28, 0) +#define ETHTOOL_COALESCE_RX_CQE_FRAMES BIT(29) +#define ETHTOOL_COALESCE_RX_CQE_NSECS BIT(30) +#define ETHTOOL_COALESCE_ALL_PARAMS GENMASK(30, 0) #define ETHTOOL_COALESCE_USECS \ (ETHTOOL_COALESCE_RX_USECS | ETHTOOL_COALESCE_TX_USECS)diff --git a/include/uapi/linux/ethtool_netlink_generated.h b/include/uapi/linux/ethtool_netlink_generated.h index 556a0c834df5..efc6e4ade77b 100644 --- a/include/uapi/linux/ethtool_netlink_generated.h +++ b/include/uapi/linux/ethtool_netlink_generated.h@@ -371,6 +371,8 @@ enum { ETHTOOL_A_COALESCE_TX_AGGR_TIME_USECS, ETHTOOL_A_COALESCE_RX_PROFILE, ETHTOOL_A_COALESCE_TX_PROFILE, + ETHTOOL_A_COALESCE_RX_CQE_FRAMES, + ETHTOOL_A_COALESCE_RX_CQE_NSECS, __ETHTOOL_A_COALESCE_CNT, ETHTOOL_A_COALESCE_MAX = (__ETHTOOL_A_COALESCE_CNT - 1)diff --git a/net/ethtool/coalesce.c b/net/ethtool/coalesce.c index 3e18ca1ccc5e..349bb02c517a 100644 --- a/net/ethtool/coalesce.c +++ b/net/ethtool/coalesce.c@@ -118,6 +118,8 @@ static int coalesce_reply_size(const struct ethnl_req_info *req_base, nla_total_size(sizeof(u32)) + /* _TX_AGGR_MAX_BYTES */ nla_total_size(sizeof(u32)) + /* _TX_AGGR_MAX_FRAMES */ nla_total_size(sizeof(u32)) + /* _TX_AGGR_TIME_USECS */ + nla_total_size(sizeof(u32)) + /* _RX_CQE_FRAMES */ + nla_total_size(sizeof(u32)) + /* _RX_CQE_NSECS */ total_modersz * 2; /* _{R,T}X_PROFILE */ }@@ -269,7 +271,11 @@ static int coalesce_fill_reply(struct sk_buff *skb, coalesce_put_u32(skb, ETHTOOL_A_COALESCE_TX_AGGR_MAX_FRAMES, kcoal->tx_aggr_max_frames, supported) || coalesce_put_u32(skb, ETHTOOL_A_COALESCE_TX_AGGR_TIME_USECS, - kcoal->tx_aggr_time_usecs, supported)) + kcoal->tx_aggr_time_usecs, supported) || + coalesce_put_u32(skb, ETHTOOL_A_COALESCE_RX_CQE_FRAMES, + kcoal->rx_cqe_frames, supported) || + coalesce_put_u32(skb, ETHTOOL_A_COALESCE_RX_CQE_NSECS, + kcoal->rx_cqe_nsecs, supported)) return -EMSGSIZE; if (!req_base->dev || !req_base->dev->irq_moder)@@ -338,6 +344,8 @@ const struct nla_policy ethnl_coalesce_set_policy[] = { [ETHTOOL_A_COALESCE_TX_AGGR_MAX_BYTES] = { .type = NLA_U32 }, [ETHTOOL_A_COALESCE_TX_AGGR_MAX_FRAMES] = { .type = NLA_U32 }, [ETHTOOL_A_COALESCE_TX_AGGR_TIME_USECS] = { .type = NLA_U32 }, + [ETHTOOL_A_COALESCE_RX_CQE_FRAMES] = { .type = NLA_U32 }, + [ETHTOOL_A_COALESCE_RX_CQE_NSECS] = { .type = NLA_U32 }, [ETHTOOL_A_COALESCE_RX_PROFILE] = NLA_POLICY_NESTED(coalesce_profile_policy), [ETHTOOL_A_COALESCE_TX_PROFILE] =@@ -570,6 +578,10 @@ __ethnl_set_coalesce(struct ethnl_req_info *req_info, struct genl_info *info, tb[ETHTOOL_A_COALESCE_TX_AGGR_MAX_FRAMES], &mod); ethnl_update_u32(&kernel_coalesce.tx_aggr_time_usecs, tb[ETHTOOL_A_COALESCE_TX_AGGR_TIME_USECS], &mod); + ethnl_update_u32(&kernel_coalesce.rx_cqe_frames, + tb[ETHTOOL_A_COALESCE_RX_CQE_FRAMES], &mod); + ethnl_update_u32(&kernel_coalesce.rx_cqe_nsecs, + tb[ETHTOOL_A_COALESCE_RX_CQE_NSECS], &mod); if (dev->irq_moder && dev->irq_moder->profile_flags & DIM_PROFILE_RX) { ret = ethnl_update_profile(dev, &dev->irq_moder->rx_profile,