Re: [PATCH net-next v7 6/6] selftests: drv-net: extend so_txtime with hw offload

[Willem de Bruijn <willemdebruijn.kernel@gmail.com>]

Willem de Bruijn wrote:
> From: Willem de Bruijn <willemb@google.com>
> 
> Add two pacing hardware offload variants
> 
> 1. one that uses FQ to safely offload when within bounds.
> 2. one that uses pfifo_fast and thus forwards all packets.
> 
> Verify that the packets are paced in hardware with new flag '-H'.
> 
> Also increase rcvtimeout significantly to reduce flakiness. Especially
> for the new beyond_hw_horizon test, which is close to the 100ms limit.
> But update recv_verify_empty to take MSG_DONTWAIT. That last empty
> check must not delay each testcase by the receive timeout.
> 
> Hardware pacing offload can complete packets out of order. So the
> reverse_order test is expected to pass with pfifo_fast too.
> 
> Do not test ETF, which does not change its dequeue behavior based on
> pacing_offload_horizon.
> 
> Signed-off-by: Willem de Bruijn <willemb@google.com>

> +@ksft_variants(_test_variants_fq())
> +def test_so_txtime_pfifofast_mono_hw(cfg, ipver, args_tx, args_rx):
> +    """Run all variants of monotonic tests, without fq pacing sw backup."""
> +    cfg.require_ipver(ipver)
> +    cfg.require_nsim(nsim_test=False)
> +
> +    _dev_setup_pacing_offload(cfg)
> +    _qdisc_setup(cfg.ifname, "pfifo_fast")
> +
> +    # Expect all tests to pass, except beyond_hw_horizon without sw fallback.
> +    # It will send immediately, failing the receiver arrival bounds check.
> +    expect_pass = not args_tx == "a,70"

Will fix a style warning

> +    test_so_txtime(cfg, "mono", ipver, f"-H {args_tx}", args_rx, expect_pass)