The branch main has been updated by kbowling: URL: https://cgit.FreeBSD.org/src/commit/?id=abe22383f1b144f0868aa0654ec4514d36f7a4f5
commit abe22383f1b144f0868aa0654ec4514d36f7a4f5 Author: Kevin Bowling <[email protected]> AuthorDate: 2026-08-08 12:26:23 +0000 Commit: Kevin Bowling <[email protected]> CommitDate: 2026-08-08 15:37:01 +0000 e1000: Correct Rx descriptor threshold programming Jumbo receive tuning on integrated controllers enabled PTHRESH without a nonzero HTHRESH, contrary to the hardware programming requirements. It also covered only the integrated MAC generations present when the workaround was added. Enumerate every jumbo-capable ICH and PCH type and program PTHRESH=3 with HTHRESH=1. Linux fixed the same HTHRESH omission in b701cacdbcfb. The 82574 path combined threshold values with the reset values using bitwise OR. Requesting WTHRESH=4 while the reset value was one thus programmed five. Clear the complete threshold fields before installing the established PTHRESH=32, HTHRESH=4, WTHRESH=4 descriptor-granularity policy. MFC after: 2 weeks --- sys/dev/e1000/if_em.c | 50 ++++++++++++++++++++++++++++++++++++-------------- sys/dev/e1000/if_em.h | 13 +++++++++++++ 2 files changed, 49 insertions(+), 14 deletions(-) diff --git a/sys/dev/e1000/if_em.c b/sys/dev/e1000/if_em.c index e7bc457ed1bd..b14087f2c88c 100644 --- a/sys/dev/e1000/if_em.c +++ b/sys/dev/e1000/if_em.c @@ -4419,6 +4419,27 @@ igb_initialize_receive_rings(if_ctx_t ctx, bool drop) } } +static bool +em_integrated_jumbo_rx(struct e1000_hw *hw) +{ + switch (hw->mac.type) { + case e1000_ich9lan: + case e1000_ich10lan: + case e1000_pchlan: + case e1000_pch2lan: + case e1000_pch_lpt: + case e1000_pch_spt: + case e1000_pch_cnp: + case e1000_pch_tgp: + case e1000_pch_adp: + case e1000_pch_mtp: + case e1000_pch_ptp: + return (true); + default: + return (false); + } +} + static void em_initialize_receive_unit(if_ctx_t ctx) { @@ -4562,24 +4583,25 @@ em_initialize_receive_unit(if_ctx_t ctx) E1000_WRITE_REG(hw, E1000_RDT(qid), 0); } - /* - * Set PTHRESH for improved jumbo performance - * According to 10.2.5.11 of Intel 82574 Datasheet, - * RXDCTL(1) is written whenever RXDCTL(0) is written. - * Only write to RXDCTL(1) if there is a need for different - * settings. - */ - if ((hw->mac.type == e1000_ich9lan || hw->mac.type == e1000_pch2lan || - hw->mac.type == e1000_ich10lan) && if_getmtu(ifp) > ETHERMTU) { + /* Increase receive-descriptor prefetching for integrated jumbo MACs. */ + if (em_integrated_jumbo_rx(hw) && if_getmtu(ifp) > ETHERMTU) { u32 rxdctl = E1000_READ_REG(hw, E1000_RXDCTL(0)); - E1000_WRITE_REG(hw, E1000_RXDCTL(0), rxdctl | 3); + + rxdctl &= ~(EM_RXDCTL_PTHRESH_MASK | + EM_RXDCTL_HTHRESH_MASK); + rxdctl |= EM_JUMBO_RX_PTHRESH | + (EM_JUMBO_RX_HTHRESH << 8); + E1000_WRITE_REG(hw, E1000_RXDCTL(0), rxdctl); } else if (hw->mac.type == e1000_82574) { + /* RXDCTL(0) writes are mirrored to RXDCTL(1) on 82574. */ for (int i = 0; i < sc->rx_num_queues; i++) { u32 rxdctl = E1000_READ_REG(hw, E1000_RXDCTL(i)); - rxdctl |= 0x20; /* PTHRESH */ - rxdctl |= 4 << 8; /* HTHRESH */ - rxdctl |= 4 << 16;/* WTHRESH */ - rxdctl |= 1 << 24; /* Switch to granularity */ + + rxdctl &= ~EM_RXDCTL_THRESH_MASK; + rxdctl |= EM_82574_RX_PTHRESH | + (EM_82574_RX_HTHRESH << 8) | + (EM_82574_RX_WTHRESH << 16) | + E1000_RXDCTL_THRESH_UNIT_DESC; E1000_WRITE_REG(hw, E1000_RXDCTL(i), rxdctl); } } else if (hw->mac.type >= igb_mac_min) { diff --git a/sys/dev/e1000/if_em.h b/sys/dev/e1000/if_em.h index 5f53f4074fcf..99d4e9d02309 100644 --- a/sys/dev/e1000/if_em.h +++ b/sys/dev/e1000/if_em.h @@ -300,6 +300,19 @@ struct igb_vf_mac_filter; #define EM_TX_HTHRESH 1 #define EM_TX_WTHRESH 1 +#define EM_RXDCTL_PTHRESH_MASK 0x0000003F +#define EM_RXDCTL_HTHRESH_MASK 0x00003F00 +#define EM_RXDCTL_WTHRESH_MASK 0x003F0000 +#define EM_RXDCTL_THRESH_MASK (EM_RXDCTL_PTHRESH_MASK | \ + EM_RXDCTL_HTHRESH_MASK | \ + EM_RXDCTL_WTHRESH_MASK) + +#define EM_JUMBO_RX_PTHRESH 3 +#define EM_JUMBO_RX_HTHRESH 1 +#define EM_82574_RX_PTHRESH 32 +#define EM_82574_RX_HTHRESH 4 +#define EM_82574_RX_WTHRESH 4 + #define IGB_RX_PTHRESH ((hw->mac.type == e1000_i354) ? 12 : \ ((hw->mac.type <= e1000_82576) ? 16 : 8)) #define IGB_RX_HTHRESH 8
