Re: [PATCH net-next 3/4] ethtool: Support for configurable RSS hash key.

[Ben Hutchings <ben@decadent.org.uk>]

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On Mon, 2014-01-20 at 12:23 +0000, Venkata Duvvuru wrote:
[...]
> > > +/* RSS Hash key */
> > > +struct ethtool_rss_hkey {
> > > +	__u32   cmd;            /* ETHTOOL_SET/GET_RSS_HKEY */
> > > +	__u8    data[RSS_HASH_KEY_LEN];
> > > +	__u32	data_len;
> > > +};
> > [...]
> > 
> > How about putting data after the data_len and giving it a length of 0, so this is
> > extensible to an arbitrary length key?
> > 
> > If we're extending the RSS configuration interface, there are a few other
> > things that might be worth doing at the same time:
> > 
> > - Single commands to get/set both the key and the indirection table at the
> > same time
> > - Add a field to distinguish multiple RSS contexts (some hardware can use RSS
> > contexts together with filters, though RX NFC does not support that yet)
> Are you referring to the filter-id that is created at the time of config-nfc? Pls clarify.

No, what I mean is:

1. An RX flow steering filter can specify use of RSS, in which case the
value looked up in the indirection is added to the queue number
specified in the filter.  This is not yet controllable through RX NFC
though there is room for extension there.

2. Multi-function controllers need multiple RSS contexts (key +
indirection table) to support independent use of RSS on each function.
But it may also be possible to allocate multiple contexts to a single
function.  This could be useful in conjunction with 1.  But there would
need to be a way to allocate and configure extra contexts first.

Ben.

-- 
Ben Hutchings
One of the nice things about standards is that there are so many of them.

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