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Message-ID: <f6dcafd5-69c1-4981-84da-e7683e84833d@amd.com>
Date: Thu, 13 Feb 2025 09:38:20 -0800
From: Brett Creeley <bcreeley@....com>
To: Mohsin Bashir <mohsin.bashr@...il.com>, netdev@...r.kernel.org
Cc: alexanderduyck@...com, kuba@...nel.org, andrew+netdev@...n.ch,
davem@...emloft.net, edumazet@...gle.com, pabeni@...hat.com,
linux@...linux.org.uk, sanman.p211993@...il.com, vadim.fedorenko@...ux.dev,
suhui@...china.com, horms@...nel.org, sdf@...ichev.me, jdamato@...tly.com,
brett.creeley@....com, przemyslaw.kitszel@...el.com, kernel-team@...a.com
Subject: Re: [PATCH net-next] eth: fbnic: Add ethtool support for IRQ
coalescing
On 2/12/2025 3:49 PM, Mohsin Bashir wrote:
> Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding.
>
>
> Add ethtool support to configure the IRQ coalescing behavior. Support
> separate timers for Rx and Tx for time based coalescing. For frame based
> configuration, currently we only support the Rx side.
>
> The hardware allows configuration of descriptor count instead of frame
> count requiring conversion between the two. We assume 2 descriptors
> per frame, one for the metadata and one for the data segment.
>
> When rx-frames are not configured, we set the RX descriptor count to
> half the ring size as a fail safe.
>
> Default configuration:
> ethtool -c eth0 | grep -E "rx-usecs:|tx-usecs:|rx-frames:"
> rx-usecs: 30
> rx-frames: 0
> tx-usecs: 35
>
> IRQ rate test:
> With single iperf flow we monitor IRQ rate while changing the tx-usesc and
> rx-usecs to high and low values.
>
> ethtool -C eth0 rx-frames 8192 rx-usecs 150 tx-usecs 150
> irq/sec 13k
> irq/sec 14k
> irq/sec 14k
>
> ethtool -C eth0 rx-frames 8192 rx-usecs 10 tx-usecs 10
> irq/sec 27k
> irq/sec 28k
> irq/sec 28k
>
> Signed-off-by: Mohsin Bashir <mohsin.bashr@...il.com>
> ---
> drivers/net/ethernet/meta/fbnic/fbnic.h | 3 +
> .../net/ethernet/meta/fbnic/fbnic_ethtool.c | 52 ++++++++++++++++++
> .../net/ethernet/meta/fbnic/fbnic_netdev.c | 4 ++
> .../net/ethernet/meta/fbnic/fbnic_netdev.h | 6 ++
> drivers/net/ethernet/meta/fbnic/fbnic_txrx.c | 55 ++++++++++++++++---
> drivers/net/ethernet/meta/fbnic/fbnic_txrx.h | 3 +
> 6 files changed, 115 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/net/ethernet/meta/fbnic/fbnic.h b/drivers/net/ethernet/meta/fbnic/fbnic.h
> index 14751f16e125..548e882381ce 100644
> --- a/drivers/net/ethernet/meta/fbnic/fbnic.h
> +++ b/drivers/net/ethernet/meta/fbnic/fbnic.h
> @@ -180,6 +180,9 @@ void fbnic_dbg_exit(void);
> void fbnic_csr_get_regs(struct fbnic_dev *fbd, u32 *data, u32 *regs_version);
> int fbnic_csr_regs_len(struct fbnic_dev *fbd);
>
> +void fbnic_config_txrx_usecs(struct fbnic_napi_vector *nv, u32 arm);
> +void fbnic_config_rx_frames(struct fbnic_napi_vector *nv);
> +
> enum fbnic_boards {
> fbnic_board_asic
> };
> diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c b/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c
> index 20cd9f5f89e2..7a149d73edb5 100644
> --- a/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c
> +++ b/drivers/net/ethernet/meta/fbnic/fbnic_ethtool.c
> @@ -135,6 +135,54 @@ static void fbnic_clone_free(struct fbnic_net *clone)
> kfree(clone);
> }
>
> +static int fbnic_get_coalesce(struct net_device *netdev,
> + struct ethtool_coalesce *ec,
> + struct kernel_ethtool_coalesce *kernel_coal,
> + struct netlink_ext_ack *extack)
> +{
> + struct fbnic_net *fbn = netdev_priv(netdev);
> +
> + ec->tx_coalesce_usecs = fbn->tx_usecs;
> + ec->rx_coalesce_usecs = fbn->rx_usecs;
> + ec->rx_max_coalesced_frames = fbn->rx_max_frames;
> +
> + return 0;
> +}
> +
> +static int fbnic_set_coalesce(struct net_device *netdev,
> + struct ethtool_coalesce *ec,
> + struct kernel_ethtool_coalesce *kernel_coal,
> + struct netlink_ext_ack *extack)
> +{
> + struct fbnic_net *fbn = netdev_priv(netdev);
> +
> + /* Verify against hardware limits */
> + if (ec->rx_coalesce_usecs >
> + FIELD_MAX(FBNIC_INTR_CQ_REARM_RCQ_TIMEOUT) ||
> + ec->tx_coalesce_usecs >
> + FIELD_MAX(FBNIC_INTR_CQ_REARM_TCQ_TIMEOUT) ||
> + ec->rx_max_coalesced_frames * FBNIC_MIN_RXD_PER_FRAME >
> + FIELD_MAX(FBNIC_QUEUE_RIM_THRESHOLD_RCD_MASK))
> + return -EINVAL;
> +
> + fbn->tx_usecs = ec->tx_coalesce_usecs;
> + fbn->rx_usecs = ec->rx_coalesce_usecs;
> + fbn->rx_max_frames = ec->rx_max_coalesced_frames;
> +
> + if (netif_running(netdev)) {
> + int i;
> +
> + for (i = 0; i < fbn->num_napi; i++) {
> + struct fbnic_napi_vector *nv = fbn->napi[i];
> +
> + fbnic_config_txrx_usecs(nv, 0);
> + fbnic_config_rx_frames(nv);
> + }
> + }
> +
> + return 0;
> +}
> +
> static void fbnic_get_strings(struct net_device *dev, u32 sset, u8 *data)
> {
> int i;
> @@ -586,9 +634,13 @@ fbnic_get_eth_mac_stats(struct net_device *netdev,
> }
>
> static const struct ethtool_ops fbnic_ethtool_ops = {
> + .supported_coalesce_params = ETHTOOL_COALESCE_USECS |
> + ETHTOOL_COALESCE_RX_MAX_FRAMES,
> .get_drvinfo = fbnic_get_drvinfo,
> .get_regs_len = fbnic_get_regs_len,
> .get_regs = fbnic_get_regs,
> + .get_coalesce = fbnic_get_coalesce,
> + .set_coalesce = fbnic_set_coalesce,
> .get_strings = fbnic_get_strings,
> .get_ethtool_stats = fbnic_get_ethtool_stats,
> .get_sset_count = fbnic_get_sset_count,
> diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_netdev.c b/drivers/net/ethernet/meta/fbnic/fbnic_netdev.c
> index 1db57c42333e..8b6be6b60945 100644
> --- a/drivers/net/ethernet/meta/fbnic/fbnic_netdev.c
> +++ b/drivers/net/ethernet/meta/fbnic/fbnic_netdev.c
> @@ -618,6 +618,10 @@ struct net_device *fbnic_netdev_alloc(struct fbnic_dev *fbd)
> fbn->ppq_size = FBNIC_PPQ_SIZE_DEFAULT;
> fbn->rcq_size = FBNIC_RCQ_SIZE_DEFAULT;
>
> + fbn->tx_usecs = FBNIC_TX_USECS_DEFAULT;
> + fbn->rx_usecs = FBNIC_RX_USECS_DEFAULT;
> + fbn->rx_max_frames = FBNIC_RX_FRAMES_DEFAULT;
> +
> default_queues = netif_get_num_default_rss_queues();
> if (default_queues > fbd->max_num_queues)
> default_queues = fbd->max_num_queues;
> diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_netdev.h b/drivers/net/ethernet/meta/fbnic/fbnic_netdev.h
> index a392ac1cc4f2..46af92a8f781 100644
> --- a/drivers/net/ethernet/meta/fbnic/fbnic_netdev.h
> +++ b/drivers/net/ethernet/meta/fbnic/fbnic_netdev.h
> @@ -12,6 +12,7 @@
> #include "fbnic_txrx.h"
>
> #define FBNIC_MAX_NAPI_VECTORS 128u
> +#define FBNIC_MIN_RXD_PER_FRAME 2
>
> struct fbnic_net {
> struct fbnic_ring *tx[FBNIC_MAX_TXQS];
> @@ -27,6 +28,11 @@ struct fbnic_net {
> u32 ppq_size;
> u32 rcq_size;
>
> + u16 rx_usecs;
> + u16 tx_usecs;
> +
> + u32 rx_max_frames;
> +
> u16 num_napi;
>
> struct phylink *phylink;
> diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_txrx.c b/drivers/net/ethernet/meta/fbnic/fbnic_txrx.c
> index d4d7027df9a0..978dce1e4eaa 100644
> --- a/drivers/net/ethernet/meta/fbnic/fbnic_txrx.c
> +++ b/drivers/net/ethernet/meta/fbnic/fbnic_txrx.c
> @@ -2010,9 +2010,53 @@ static void fbnic_config_drop_mode_rcq(struct fbnic_napi_vector *nv,
> fbnic_ring_wr32(rcq, FBNIC_QUEUE_RDE_CTL0, rcq_ctl);
> }
>
> +static void fbnic_config_rim_threshold(struct fbnic_ring *rcq, u16 nv_idx, u32 rx_desc)
> +{
> + u32 threshold;
> +
> + /* Set the threshold to half the ring size if rx_frames
> + * is not configured
> + */
> + threshold = rx_desc ? : rcq->size_mask / 2;
> +
> + fbnic_ring_wr32(rcq, FBNIC_QUEUE_RIM_CTL, nv_idx);
> + fbnic_ring_wr32(rcq, FBNIC_QUEUE_RIM_THRESHOLD, threshold);
> +}
> +
> +void fbnic_config_txrx_usecs(struct fbnic_napi_vector *nv, u32 arm)
> +{
> + struct fbnic_net *fbn = netdev_priv(nv->napi.dev);
> + struct fbnic_dev *fbd = nv->fbd;
> + u32 val = arm;
> +
> + val |= FIELD_PREP(FBNIC_INTR_CQ_REARM_RCQ_TIMEOUT, fbn->rx_usecs) |
> + FBNIC_INTR_CQ_REARM_RCQ_TIMEOUT_UPD_EN;
> + val |= FIELD_PREP(FBNIC_INTR_CQ_REARM_TCQ_TIMEOUT, fbn->tx_usecs) |
> + FBNIC_INTR_CQ_REARM_TCQ_TIMEOUT_UPD_EN;
> +
> + fbnic_wr32(fbd, FBNIC_INTR_CQ_REARM(nv->v_idx), val);
> +}
> +
> +void fbnic_config_rx_frames(struct fbnic_napi_vector *nv)
> +{
> + struct fbnic_net *fbn = netdev_priv(nv->napi.dev);
> + struct fbnic_q_triad *qt;
> + int i, t;
> +
> + t = nv->txt_count;
> +
> + for (i = 0; i < nv->rxt_count; i++, t++) {
> + qt = &nv->qt[t];
Tiny nit, but struct fbnic_q_triad's scope can be reduced to this for loop.
Another nit.. This logic is a bit confusing to me, but I'm not familiar
with the fnbic driver, so maybe that's why.
Would something like this make sense? Then the need for the extra t
local variable is removed as well.
for (i = nv->txt_count; i < nv->rxt_count + nv->txt_count; i++) {...}
> + fbnic_config_rim_threshold(&qt->cmpl, nv->v_idx,
> + fbn->rx_max_frames *
> + FBNIC_MIN_RXD_PER_FRAME);
> + }
> +}
> +
> static void fbnic_enable_rcq(struct fbnic_napi_vector *nv,
> struct fbnic_ring *rcq)
> {
> + struct fbnic_net *fbn = netdev_priv(nv->napi.dev);
> u32 log_size = fls(rcq->size_mask);
> u32 rcq_ctl;
>
> @@ -2040,8 +2084,8 @@ static void fbnic_enable_rcq(struct fbnic_napi_vector *nv,
> fbnic_ring_wr32(rcq, FBNIC_QUEUE_RCQ_SIZE, log_size & 0xf);
>
> /* Store interrupt information for the completion queue */
> - fbnic_ring_wr32(rcq, FBNIC_QUEUE_RIM_CTL, nv->v_idx);
> - fbnic_ring_wr32(rcq, FBNIC_QUEUE_RIM_THRESHOLD, rcq->size_mask / 2);
> + fbnic_config_rim_threshold(rcq, nv->v_idx, fbn->rx_max_frames *
> + FBNIC_MIN_RXD_PER_FRAME);
> fbnic_ring_wr32(rcq, FBNIC_QUEUE_RIM_MASK, 0);
>
> /* Enable queue */
> @@ -2080,12 +2124,7 @@ void fbnic_enable(struct fbnic_net *fbn)
>
> static void fbnic_nv_irq_enable(struct fbnic_napi_vector *nv)
> {
> - struct fbnic_dev *fbd = nv->fbd;
> - u32 val;
> -
> - val = FBNIC_INTR_CQ_REARM_INTR_UNMASK;
> -
> - fbnic_wr32(fbd, FBNIC_INTR_CQ_REARM(nv->v_idx), val);
> + fbnic_config_txrx_usecs(nv, FBNIC_INTR_CQ_REARM_INTR_UNMASK);
> }
>
> void fbnic_napi_enable(struct fbnic_net *fbn)
> diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_txrx.h b/drivers/net/ethernet/meta/fbnic/fbnic_txrx.h
> index c2a94f31f71b..483e11e8bf39 100644
> --- a/drivers/net/ethernet/meta/fbnic/fbnic_txrx.h
> +++ b/drivers/net/ethernet/meta/fbnic/fbnic_txrx.h
> @@ -31,6 +31,9 @@ struct fbnic_net;
> #define FBNIC_HPQ_SIZE_DEFAULT 256
> #define FBNIC_PPQ_SIZE_DEFAULT 256
> #define FBNIC_RCQ_SIZE_DEFAULT 1024
> +#define FBNIC_TX_USECS_DEFAULT 35
> +#define FBNIC_RX_USECS_DEFAULT 30
> +#define FBNIC_RX_FRAMES_DEFAULT 0
>
> #define FBNIC_RX_TROOM \
> SKB_DATA_ALIGN(sizeof(struct skb_shared_info))
> --
> 2.43.5
>
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