enabling/disabling trampoline

Jacob Gorm Hansen jg at ioi.dk
Mon Mar 10 17:29:12 CET 2003

On Mon, 2003-03-10 at 15:54, Cristiano Ligieri Pereira wrote:
> Actually what I'm doing is trying the reproduce some of the results from
> the paper "The performance of micro-kernel Based Systems" using
> lmbench/hbench/AIM benchmarks on a P4 machine. I'm not quite sure if I
> understood what you mean by generating a new C library. Where is the code
> for the C library in the source tree?. Isn't there a piece of code
> handling all system calls in which I could just change it instead of
> changing every occurrence of "int 0x80" in my code?

Most programs are dynamically linked to libc, which performs the actual
linux syscalls. What you need is a version of glibc which invokes L4 by
calling into the trampoline code already present in the address space of
each l4linux process in the 'emulib' pages at 0xa0008000 instead of
using the normal int $0x80 trap instruction. Unfortunately, I do not
think a patched version of glibc exists. If you wish, you can roll your
own by downloading the source of glibc, and patching it according to
Frank's instructions, compile it, and install it into the library path
of your benchmark applications. If anyone has or is able to produce a
patch and more elaborate installation instructions, I would be very
interested in receiving a copy.

Best regards,

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