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ramips: add two-way hashing scheme for MT7621

Sometimes the tuples might be hashed to the same FOE entry.
When this hash collision problem occurs, some of the
connections will not be bound and consequently the CPU
idle rate cannot reach 100%. Therefore, two-way hashing
is adopted to alleviate this problem.

Signed-off-by: HsiuWen Yen <>
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HenryHsiu authored and blogic committed Jan 7, 2019
1 parent b3664bc commit 6b9bdbd4935d3a9c8f22dde5d84abd173a1573ce
Showing with 11 additions and 0 deletions.
  1. +11 −0 target/linux/ramips/files-4.14/drivers/net/ethernet/mediatek/mtk_offload.c
@@ -118,6 +118,13 @@ mtk_foe_set_mac(struct mtk_foe_entry *entry, u8 *smac, u8 *dmac)
entry->ipv4_hnapt.smac_lo = swab16(*((u16*) &smac[4]));

static int
mtk_check_hashcollision(struct mtk_eth *eth, u32 hash)
struct mtk_foe_entry entry = ((struct mtk_foe_entry *)eth->foe_table)[hash];
return (entry.bfib1.state != BIND)? 0:1;

static void
mtk_foe_write(struct mtk_eth *eth, u32 hash,
struct mtk_foe_entry *entry)
@@ -173,6 +180,10 @@ int mtk_flow_offload(struct mtk_eth *eth,
goto write;

if(mtk_check_hashcollision(eth, ohash)) // Two-way hash: when hash collision occurs, the hash value will be shifted to the next position.
ohash += 1;
if(mtk_check_hashcollision(eth, rhash))
rhash += 1;
mtk_foe_set_mac(&orig, dest->eth_src, dest->eth_dest);
mtk_foe_set_mac(&reply, src->eth_src, src->eth_dest);

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