Re: [PATCH net-next v3 4/4] selftests: drv-net: add a simple TSO test

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

Jakub Kicinski wrote:
> Add a simple test for TSO. Send a few MB of data and check device
> stats to verify that the device was performing segmentation.
> Do the same thing over a few tunnel types.
> 
> Injecting GSO packets directly would give us more ability to test
> corner cases, but perhaps starting simple is good enough?
> 
>   # ./ksft-net-drv/drivers/net/hw/tso.py
>   # Detected qstat for LSO wire-packets
>   KTAP version 1
>   1..14
>   ok 1 tso.ipv4 # SKIP Test requires IPv4 connectivity
>   ok 2 tso.vxlan4_ipv4 # SKIP Test requires IPv4 connectivity
>   ok 3 tso.vxlan6_ipv4 # SKIP Test requires IPv4 connectivity
>   ok 4 tso.vxlan_csum4_ipv4 # SKIP Test requires IPv4 connectivity
>   ok 5 tso.vxlan_csum6_ipv4 # SKIP Test requires IPv4 connectivity
>   ok 6 tso.gre4_ipv4 # SKIP Test requires IPv4 connectivity
>   ok 7 tso.gre6_ipv4 # SKIP Test requires IPv4 connectivity
>   ok 8 tso.ipv6
>   ok 9 tso.vxlan4_ipv6
>   ok 10 tso.vxlan6_ipv6
>   ok 11 tso.vxlan_csum4_ipv6
>   ok 12 tso.vxlan_csum6_ipv6
>   ok 13 tso.gre4_ipv6
>   ok 14 tso.gre6_ipv6
>   # Totals: pass:7 fail:0 xfail:0 xpass:0 skip:7 error:0
> 
> Note that the test currently depends on the driver reporting
> the LSO count via qstat, which appears to be relatively rare
> (virtio, cisco/enic, sfc/efc; but virtio needs host support).
> 
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
> v3:
>  - rework after the v4/v6 address split
> v2: https://lore.kernel.org/20250214234631.2308900-4-kuba@kernel.org
>  - lower max noise
>  - mention header overhead in the comment
>  - fix the basic v4 TSO feature name
>  - also run a stream with just GSO partial for tunnels
> v1: https://lore.kernel.org/20250213003454.1333711-4-kuba@kernel.org

> +def test_builder(name, cfg, ipver, feature, tun=None, inner_ipver=None):
> +    """Construct specific tests from the common template."""
> +    def f(cfg):
> +        cfg.require_ipver(ipver)
> +
> +        if not cfg.have_stat_super_count and \
> +           not cfg.have_stat_wire_count:
> +            raise KsftSkipEx(f"Device does not support LSO queue stats")
> +
> +        if tun:
> +            remote_v4, remote_v6 = build_tunnel(cfg, ipver, tun)
> +        else:
> +            remote_v4 = cfg.remote_addr_v["4"]
> +            remote_v6 = cfg.remote_addr_v["6"]
> +
> +        tun_partial = tun and tun[1]
> +        has_gso_partial = tun and 'tx-gso-partial' in cfg.features
> +
> +        # First test without the feature enabled.
> +        ethtool(f"-K {cfg.ifname} {feature} off")
> +        if has_gso_partial:
> +            ethtool(f"-K {cfg.ifname} tx-gso-partial off")
> +        run_one_stream(cfg, ipver, remote_v4, remote_v6, should_lso=False)
> +
> +        # Now test with the feature enabled.
> +        # For compatible tunnels only - just GSO partial, not specific feature.
> +        if has_gso_partial:
> +            ethtool(f"-K {cfg.ifname} tx-gso-partial on")
> +            run_one_stream(cfg, ipver, remote_v4, remote_v6,
> +                           should_lso=tun_partial)
> +
> +        # Full feature enabled.
> +        if feature in cfg.features:
> +            ethtool(f"-K {cfg.ifname} {feature} on")
> +            run_one_stream(cfg, ipver, remote_v4, remote_v6, should_lso=True)
> +        else:
> +            raise KsftXfailEx(f"Device does not support {feature}")
> +
> +    f.__name__ = name + ((ipver + "_") if tun else "") + "ipv" + ipver

use inner_ipver if tun?

based on previous version of the patch:

    +    if tun:
    +        name += ("4" if inner_ipv4 else "6") + "_"


> +    return f
> +