> On Aug. 8, 2012, 12:08 p.m., Ali Saidi wrote:
> > Hi Anastasia, 
> > 
> > Thanks for the patches. I'm not sure exactly what we want to do with them 
> > because this changes the configuration register. I think it's certainly 
> > useful for people who want to use >4 cores, but if you need a special 
> > kernel as well I'm torn as to if we want to commit it. If you have any 
> > thoughts please let us know.
> > 
> > Thanks again for contributing!
> > 
> > Ali
> >
> 
> Nathan Binkert wrote:
>     Provided that it is not inlined (which it shouldn't be since it is in the 
> .c file), this seems like the kind of function that could be skipped (as wedo 
> for udelay) and handled by the simulator.
>     
>     [The diff doesn't apply, but I was able to see the kernel change in the 
> reject file. ]
>

True, however if you use a system that supports an A15 you don't need either 
change, although you do need a one line change to the boot loader that I'm 
going to commit any day now. The problem that then crops up is how to relate 
gem5's flat and linear cpu numbering scheme to the clustered scheme that is 
described in the A15 MPIDR register. Unfortunately, this comes back to needing 
some type of container classes (Core vs CPU) (CPU vs Cluster) ... as well as 
some sensible way to apply allow cores to get architecture specific 
configuration structures that describe things like cluster affinity level or 
CPUID if you want to model a heterogeneous system and let the kernel know that 
the cores are heterogeneous so it can make more intelligent scheduling 
decisions. 

Lastly, there has been so much churn in the linux kernel around ARM support 
lately to deal with the switch to device trees that it seems painful to try and 
deal with that at the moment. 


- Ali


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On June 6, 2012, 9:06 a.m., BUTKO Anastasiia wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> http://reviews.gem5.org/r/1250/
> -----------------------------------------------------------
> 
> (Updated June 6, 2012, 9:06 a.m.)
> 
> 
> Review request for Default.
> 
> 
> Description
> -------
> 
> ARM Full System simulation up to 8 processors / cores.
> 
> Requires modifications in both linux-2.6.38 source and 
> gem5-stable/src/dev/arm/a9scu.cc.
> 
> For the simulator: SCU register logic changed for properly reflecting cpu 
> count.
> For linux-2.6.38 : scu_get_core_count function now returns cpu count, masked 
> before. 
> 
> 
> Diffs
> -----
> 
>   linux-2.8.38/arch/arm/kernel/smp_scu.c UNKNOWN 
>   src/dev/arm/a9scu.cc UNKNOWN 
> 
> Diff: http://reviews.gem5.org/r/1250/diff/
> 
> 
> Testing
> -------
> 
> 
> Thanks,
> 
> BUTKO Anastasiia
> 
>

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