[Stgt-devel] User-mode iSER

Tom Tucker tom
Wed Aug 2 16:01:37 CEST 2006

> > 
> > I think this is the area where we will need to get fancy if we want
> > higher performance. To avoid the copy, we would have to migrate to
> > netchannels (if they every happen) or implement our own simple tear-away
> > buffer scheme on top of a socket. I think this is phase-ii, however. 
> ok, otherwise copy to user space and copy back to kernel for disk = low
> performance. yes, direct io can be used here, but then u lose whole
> cache benefits.

Can you elaborate on the loss of "whole cache benefits". 

> you need an in-kernel target mode driver for FCP HBA. and i think this
> are one type of transports.

One possibility is to move up the kernel/user line to just above the
network provider layer and make this a zero-copy interface. This would
support zcopy for TCP, FC and RDMA. 

I don't think you would want this to be a netlink based interface,
however, I think you would want it to be a syscall (or ioctl)
interface...and this makes me worry that the Linux kernel guys wouldn't
like that.

> > 

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