plugin_net: handle cqe-mode-rx ethtool option

[rtzoeller]

Parsing ethtool output has been broken for several years, since ethtool -c started producing a line resembling CQE mode RX: n/a TX: n/a. This prevents setting any [net] coalesce= options, which log tuned.plugins.plugin_net: unknown coalesce parameter(s): {'CQE mode RX'}.

Substituting cqe-mode-rx: for CQE mode RX: resolves the issue, although there is a conflict with the adaptive-tx workaround which prevents us from supporting cqe-mode-tx directly. Do not attempt to address that issue as part of this change.

Fixes #726.

[rtzoeller]

@yarda any chance of getting this (or a variant of it) into 2.25.0? It resolves an issue that's breaking documented configurations in plugin_net.

[yarda]

@yarda any chance of getting this (or a variant of it) into 2.25.0? It resolves an issue that's breaking documented configurations in plugin_net.

Thanks, LGTM, I am counting with it for the 2.25.0 release.

Regarding, the cqe-mode-tx, I think it will require two regex runs (if the current parsing is reused), e.g.:

value = re.sub(r"([^:\n]+)(\s+RX:\s+[^:]+\s+)TX:", "\\1\\2\n\\1 TX:", value)
value = self._cmd.multiple_re_replace({
    "Adaptive RX:": "adaptive-rx:",
    "Adaptive TX:": "adaptive-tx:",
    "CQE mode RX:":"cqe-mode-rx:",
    "CQE mode TX:":"cqe-mode-tx:",
...