Re: Intel P6 vs P7 system call performance

Date: Thu Dec 19 2002 - 08:55:15 EST

On 19 Dec, Dave Jones wrote:
> On Thu, Dec 19, 2002 at 02:22:36PM +0100, wrote:
> > > However, there's another issue, namely process startup cost. I personally
> > > want it to be as light as at all possible. I hate doing an "strace" on
> > > user processes and seeing tons and tons of crapola showing up. Just for
> > So why not map the magic page at 0xffffe000 at some other address as
> > well?
> > Static binaries can just directly jump/call into the magic page.
> .. and explode nicely when you try to run them on an older kernel
> without the new syscall magick. This is what Linus' first
> proof-of-concept code did.

True, but unless I really don't get it, compatibility of a new static
binary with an old kernel is going to break anyway.
My point was that the double-mapped page trick adds no overhead in the
case of a static binary, and just one extra mmap in case of a shared


> Dave

Bart Hartgers - TUE Eindhoven
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