[LNT][Patch] Bug 16261 - lnt incorrectly builds timeit-target when one is using a simulator

[Doug Gilmore]

On Tue, 2013-07-23 at 17:17 -0700, an Reed Kotler wrote:
> 
> In this case we are not using lnt under Qemu user mode for benchmarking; 
> just as a way to run test-suite to test whether the code is correct.
> 
> Qemu user mode emulates target instructions, but when it gets a Unix 
> Kernel trap, it uses the host to emulate those.
> 
> For example, file I/O.
> 
> It is possible to run target timeit under qemu and let it launch the app 
> or a wrapper.
> (But it is more limited as to what can be done here under qemu vs under 
> the host OS directly).
> 
> For time functions, it is also going to use the host to emulate those.
> 
> So whether timeit is running under qemu or directly on the host, the 
> answers regarding time will be the same.
> 
> But running timeit under qemu will be much slower as far as elapsed time 
> than running it on the host directly.
> 
> We would also need to add some new mechanism to Lnt or the makefiles to 
> also wrap timeit.
Good point Reed -- thanks!
> 
> Reed
> 
> 
> On 07/23/2013 02:19 PM, Daniel Dunbar wrote:
> > Wouldn't it be a more accurate simulation to run timeit-target under 
> > the emulator as well? Or is that too much to ask?
> >
> >  - Daniel
Hi Daniel,

I agree with Reed's discussion of the issues.  We are mainly concerned with
the correctness when running under QEMU, though the the timing data
might be useful at a very course grain level.

Doug
> >
> >
> > On Mon, Jul 22, 2013 at 6:47 PM, Reed Kotler <rkotler at mips.com 
> > <mailto:rkotler at mips.com>> wrote:
> > ...