Likely the entire instruction footprint fits in the L1 i cache and
there is very little re-use on the data side. Removing the L2 probably
lowers the access time to main memory by a substantial amount which
improve performance. 

Ali 

On 02.07.2012 20:06, Nyunyi Tshibangu
wrote: 

> I am having hardtime understanding the number of cycles from
SE mode statistcs 
> 
> 1)running with L1 only 
> build/X86/gem5.opt
configs/example/se.py --cpu-type="detailed" --caches --maxinsts=10000000
--cmd=bzip2/bzip2 --options="bzip2/input.program" 
> I am getting number
of cycles as: system.cpu.numCycles 54101855 
> 2)running with L1/L2
caches
> 
> build/X86/gem5.opt configs/example/se.py
--cpu-type="detailed" --caches --l2cache --maxinsts=10000000
--cmd=bzip2/bzip2 --options="bzip2/input.program" 
> I am getting number
of cycles as: system.cpu.numCycles 82713679 
> does it make sense that
performance get worse when adding L2 cache? why is ipc worse? am I
looking at wrong info to determine instruction/cycles? 
> any idea? 
>
Thanks 
> Marcus

 
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