Re: [PATCH 0/1] staging: Add firewire-serial driver

From: Stefan Richter
Date: Tue Oct 23 2012 - 14:41:25 EST

On Oct 23 Peter Hurley wrote:
> most controllers allow spillover into
> the portion of bus cycle assigned for sync tx (which is another 4Kbytes
> per 125us).

All controllers do so and are expected to do so. Asynchronous traffic is
not supposed to depend on a cycle master being active.

> (Technical note: the actual total max for combined async
> and sync tx is 6144 bytes per 125us clock)

It depends on bus topology, transaction types, and more. For a single-hop
S400 1394a bus (vulgo FireWire 400) I once calculated 44 MB/s bandwidth of
asynchronous unified write transactions:
That's at the physical layer; link layer and application layer performances
are less than that of course.
Stefan Richter
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