github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-07-27 09:36:22 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

eth: bnxt: disable rx-copybreak by default

Browse Source 
rx-copybreak requires an extra slab allocation. Since bnxt uses
page pool frags and HDS by default, the rx-copybreak doesn't
buy us anything. The extra pressure on slab causes overload
on pre-sheaves kernels on modern AMD platforms.

In synthetic testing on net-next this patch shows little difference
but I think copybreak is "obvious waste" at this point.

Default rx-copybreak threshold to 0 / disabled.

The "copybreak" defines are really the size bounds for the Rx header
buffer. Rename them.

Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Link: https://patch.msgid.link/20260602003759.1545645-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Jakub Kicinski 2026-06-01 17:37:59 -07:00
parent ee5aee77bc
commit bd3beb5c86
3 changed files with 7 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/net/ethernet/broadcom/bnxt/bnxt.c
View File

@ -4846,11 +4846,11 @@ static void bnxt_init_ring_params(struct bnxt *bp)
{
unsigned int rx_size;
bp->rx_copybreak = BNXT_DEFAULT_RX_COPYBREAK;
bp->rx_copybreak = 0; /* rx-copybreak disabled by default */
/* Try to fit 4 chunks into a 4k page */
rx_size = SZ_1K -
NET_SKB_PAD - SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
bp->dev->cfg->hds_thresh = max(BNXT_DEFAULT_RX_COPYBREAK, rx_size);
bp->dev->cfg->hds_thresh = max(BNXT_MIN_RX_HDR_BUF, rx_size);
}
/* bp->rx_ring_size, bp->tx_ring_size, dev->mtu, BNXT_FLAG_{G|L}RO flags must
@ -4911,7 +4911,7 @@ void bnxt_set_ring_params(struct bnxt *bp)
ALIGN(max(NET_SKB_PAD, XDP_PACKET_HEADROOM), 8) -
SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
} else {
rx_size = max3(BNXT_DEFAULT_RX_COPYBREAK,
rx_size = max3(BNXT_MIN_RX_HDR_BUF,
bp->rx_copybreak,
bp->dev->cfg_pending->hds_thresh);
rx_size = SKB_DATA_ALIGN(rx_size + NET_IP_ALIGN);

4
drivers/net/ethernet/broadcom/bnxt/bnxt.h
View File

@ -36,8 +36,8 @@
#include <linux/firmware/broadcom/tee_bnxt_fw.h>
#endif
#define BNXT_DEFAULT_RX_COPYBREAK 256
#define BNXT_MAX_RX_COPYBREAK 1024
#define BNXT_MIN_RX_HDR_BUF 256
#define BNXT_MAX_RX_HDR_BUF 1024
extern struct list_head bnxt_block_cb_list;

4
drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
View File

@ -4594,7 +4594,7 @@ static int bnxt_set_tunable(struct net_device *dev,
switch (tuna->id) {
case ETHTOOL_RX_COPYBREAK:
rx_copybreak = *(u32 *)data;
if (rx_copybreak > BNXT_MAX_RX_COPYBREAK)
if (rx_copybreak > BNXT_MAX_RX_HDR_BUF)
return -ERANGE;
if (rx_copybreak != bp->rx_copybreak) {
if (netif_running(dev))
@ -5172,7 +5172,7 @@ static int bnxt_run_loopback(struct bnxt *bp)
cpr = &rxr->bnapi->cp_ring;
if (bp->flags & BNXT_FLAG_CHIP_P5_PLUS)
cpr = rxr->rx_cpr;
pkt_size = min(bp->dev->mtu + ETH_HLEN, max(BNXT_DEFAULT_RX_COPYBREAK,
pkt_size = min(bp->dev->mtu + ETH_HLEN, max(BNXT_MIN_RX_HDR_BUF,
bp->rx_copybreak));
skb = netdev_alloc_skb(bp->dev, pkt_size);
if (!skb)