Re: [PATCH 0/5] ftrace: to kill a daemon

[Bodo Eggert <7eggert@gmx.de>]

On Sat, 9 Aug 2008, Steven Rostedt wrote:
> On Sat, 9 Aug 2008, Bodo Eggert wrote:
> > Steven Rostedt <rostedt@goodmis.org> wrote:
> > > On Sat, 9 Aug 2008, Andi Kleen wrote:
> > >> Steven Rostedt <rostedt@goodmis.org> writes:

> > >> > I'm stubborn, I want to get it right _and_ keep it fast.
> > >> 
> > >> For me it would seem better to just not use two part 5 byte nops
> > >> instead of adding such hacks.  I doubt there are that many of them
> > >> anyways. I bet you won't be able to measure any difference between the
> > >> different nop types in any macro benchmark.
> > > 
> > > I wish we had a true 5 byte nop. The alternative is a jmp 0, which is
> > > measurable.
> > 
> > Did you try short jumps? (0xeb 0x03 0x?? 0x?? 0x??)
> 
> What would those last three bytes be?

Anything, since the CPU will ignore them.

My hope is that different kinds of jump will behaver differently,
but I fear the side effect of the jmp (reread memory in case of 
self-modifying code) will cause the CPU to slow down anyway.
-- 
Is reading in the bathroom considered Multitasking?