Messages in this thread | | | Date | Sat, 9 Aug 2008 16:42:11 +0200 (CEST) | From | Bodo Eggert <> | Subject | Re: [PATCH 0/5] ftrace: to kill a daemon |
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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?
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