enabling/disabling trampoline

Cristiano Ligieri Pereira cpereira at ics.uci.edu
Thu Mar 13 01:24:47 CET 2003

thanks for answering. I'm really tight on my schedule to try such major
change. I guess I will have to just forget about it for now. 

How was it done in the previous version of l4? The one written in
assembly. And does the assembly version (hazelnut?) work fine on pentium 4

the problem is that Fiasco seems to be performing pretty bad on the same
benchmarsk presented in the paper "The performance of micro-kernel Based
Systems" and I'm wondering why. My first guess was the trampoline
mechanism. I using a Pentium 4 1.3Ghz machine and was expecting a smoother
performance degradation (compared to the paper) even though executing a
different version of l4 (fiasco instead of the assembly version


Cristiano Ligieri Pereira - http://www.ics.uci.edu/~cpereira

On 10 Mar 2003, Jacob Gorm Hansen wrote:

> 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,
> Jacob
> _______________________________________________
> l4-hackers mailing list
> l4-hackers at os.inf.tu-dresden.de
> http://os.inf.tu-dresden.de/mailman/listinfo/l4-hackers

More information about the l4-hackers mailing list