[openib-general] Re: [PATCH] TX/RX_RING_SIZE as loadable parameters

[Roland Dreier]

    Thomas> In fact, a large device ring means you probably only need
    Thomas> a small tx queue.  But tuning this stuff can be a black
    Thomas> art. Generally there is no reason to want a silly-large tx
    Thomas> ring. Besides, IPoIB only ever has one message in flight,
    Thomas> right?

No, IPoIB can have arbitrarily many packets in flight.  It's just like
any other layer 2 net device in that respect.

    Thomas> All these numbers should be settable per-interface, and
    Thomas> should attempt to adhere to the principle of least
    Thomas> surprise - do what other drivers in net/ do.

There isn't much uniformity about this in drivers/net.

Unfortunately, making the ring sizes settable per-interface leads to a
lot of ugly option handling code.  Is it relly important, or can we
get by with one per-module setting?

 - R.