tc-mqprio can select whether traffic classes are express or preemptible.

After some traffic tests, MAC merge layer statistics are all good.

Local device:
ethtool --include-statistics --json --show-mm eth1
[ {
        "ifname": "eth1",
        "pmac-enabled": true,
        "tx-enabled": true,
        "tx-active": true,
        "tx-min-frag-size": 60,
        "rx-min-frag-size": 60,
        "verify-enabled": true,
        "verify-time": 100,
        "max-verify-time": 128,
        "verify-status": "SUCCEEDED",
        "statistics": {
            "MACMergeFrameAssErrorCount": 0,
            "MACMergeFrameSmdErrorCount": 0,
            "MACMergeFrameAssOkCount": 0,
            "MACMergeFragCountRx": 0,
            "MACMergeFragCountTx": 35105,
            "MACMergeHoldCount": 0
        }
    } ]

Remote device:
ethtool --include-statistics --json --show-mm end1
[ {
        "ifname": "end1",
        "pmac-enabled": true,
        "tx-enabled": true,
        "tx-active": true,
        "tx-min-frag-size": 60,
        "rx-min-frag-size": 60,
        "verify-enabled": true,
        "verify-time": 100,
        "max-verify-time": 128,
        "verify-status": "SUCCEEDED",
        "statistics": {
            "MACMergeFrameAssErrorCount": 0,
            "MACMergeFrameSmdErrorCount": 0,
            "MACMergeFrameAssOkCount": 35105,
            "MACMergeFragCountRx": 35105,
            "MACMergeFragCountTx": 0,
            "MACMergeHoldCount": 0
        }
    } ]

Tested on DWMAC CORE 5.10a
Signed-off-by: Furong Xu <0x1207@gmail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://patch.msgid.link/592965ea93ed8240f0a1b8f6f8ebb8914f69419b.1725631883.git.0x1207@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>