Commit 30d19d57 authored by Magnus Karlsson's avatar Magnus Karlsson Committed by Alexei Starovoitov

ice: xsk: Eliminate unnecessary loop iteration

The NIC Tx ring completion routine cleans entries from the ring in
batches. However, it processes one more batch than it is supposed
to. Note that this does not matter from a functionality point of view
since it will not find a set DD bit for the next batch and just exit
the loop. But from a performance perspective, it is faster to
terminate the loop before and not issue an expensive read over PCIe to
get the DD bit.

Fixes: 126cdfe1 ("ice: xsk: Improve AF_XDP ZC Tx and use batching API")
Signed-off-by: default avatarMagnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220328142123.170157-3-maciej.fijalkowski@intel.com
parent a95a4d9b
......@@ -754,7 +754,7 @@ static u16 ice_clean_xdp_irq_zc(struct ice_tx_ring *xdp_ring, int napi_budget)
next_dd = next_dd + tx_thresh;
if (next_dd >= desc_cnt)
next_dd = tx_thresh - 1;
} while (budget--);
} while (--budget);
xdp_ring->next_dd = next_dd;
......
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