On Tue, 2003-07-15 at 17:01, Tom Zanussi wrote:
> Gianni Tedesco writes:
>  > On Tue, 2003-07-15 at 16:15, Tom Zanussi wrote:
>  > > The following 5 patches implement relayfs, adding a dynamic channel
>  > > resizing capability to the previously posted version.
>  > > 
>  > > relayfs is a filesystem designed to provide an efficient mechanism for
>  > > tools and facilities to relay large amounts of data from kernel space
>  > > to user space.  Full details can be found in Documentation/filesystems/
>  > > relayfs.txt.  The current version can always be found at
>  > > http://www.opersys.com/relayfs.
>  > 
>  > Could this be used to replace mmap() packet socket, how does it compare?
> 
> I think so - you could send high volumes of packet traffic to a bulk
> relayfs channel and read it from the mmap'ed relayfs file in user
> space.  The Linux Trace Toolkit does the same thing with large volumes
> of trace data - you could look at that code as an example
> (http://www.opersys.com/relayfs/ltt-on-relayfs.html).

What are the semantics of the mmap'ing the buffer? With mmaped packet
socket the userspace (read-side) requires no sys-calls apart from when
the buffer is empty, it then uses poll(2) to sleep until something new
is put in the buffer. Can relayfs do a similar thing? poll is not
mentioned in the docs...

Thanks.

-- 
// Gianni Tedesco (gianni at scaramanga dot co dot uk)
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