Subject: Re: uvm and/vs splice() (was: re: Ongoing projects)
To: Neil A. Carson <>
From: Brian Buhrow <>
List: tech-kern
Date: 05/07/1999 11:13:09
	Isn't this a faster way of implementing pipes?  pipe(2) is certainly
gluing file descriptors together for a flow of data between them.
Splice(2) or the UVM page loan mechanism could be implemented under the
pipe(2) call couldn't it?
On May 7, 11:58pm, matthew green wrote:
} Subject: uvm and/vs splice() (was: re: Ongoing projects)
} you can look at it both ways.  i like the splice() idea.  i want to,
} at the very basic level, join two fd's and pass the data between them.
} that's a common, useful operation.
} but you are right about UVM -- we should be able to provide zero-copy
} IO.  chuck has some test-data on a 'null' socket protocol using the
} page loan and/or transfer (i forget, it has a long time ago i read this
} chapter :) mechanisms that, once you got beyond the page-sized data
} manipulations, the loan/xfer stuff *really* shows.  i know that thorpej
} was interested in looking at this but he's a busy guy :)  it would be
} really neat if someone started using the cooler UVM features around
} the kernel now that mach is gone :-)
} BTW:  the splice() thread has been hashed out here before;  please check
} the archives.
>-- End of excerpt from matthew green