Re: [PATCH 1/6] staging: android: binder: Remove some funny && usage

Alan Cox
2009-06-25T08:14:19Z

On Wed, 24 Jun 2009 17:20:19 -0700
Daniel Walker <dwalker@fifo99.com> wrote:

> On Thu, 2009-06-25 at 02:01 +0200, Linus Walleij wrote:
>
> > What I really want to know, is how this relates to the vmsplice() and
> > other zero-copy buffer passing schemes already in the kernel. I was
> > sort of dreaming that D-Bus and other IPC could be accelerated on
> > top of that.
>
> Marcel had mentioned earlier in this thread that D-Bus could be
> accelerated with shared memory or moving the dbus-daemon into the
> kernel. splice() and vmplice() seem like fairly robust system calls. I
> would think they could be used also ..

Except for very large amounts of data what makes you think zero copy
buffer passing will be fast ? TLB shootdowns are expensive and they scale
horribly badly with threaded apps on multiprocessor systems ?