Thanks for pointing out this issue... Is there any other changes in default
configuration you wanna mention to simulate Nehalem like architecture ?

On Wed, Aug 22, 2012 at 10:54 AM, avadh patel <[email protected]> wrote:

>
>
> On Wed, Aug 22, 2012 at 2:16 AM, Yongbing Huang 
> <[email protected]>wrote:
>
>> Hi,****
>>
>> ** **
>>
>>          In the cache configuration files such as l2_cache.conf, there is
>> a parameter “LATENCY” for each level. What is the unit of the parameter,
>> CPU cycle or ns? I guess it is CPU cycle for caches, and ns for memory
>> option after reading the source codes. If I am right, the latencies for L2
>> (5 cycles) and L3 cache (8 cycles) shown in the example configuration, have
>> big difference from real machine which are about 10 cycles for L2 cache and
>> about 38 cycles in Nehalem architecture. Since most people use the default
>> configuration, it is valuable to make sure of this issue.****
>>
>> **
>>
>
> Yes they are CPU cycles. Can you share the document/webpage from where you
> get 10 cycles and 38 cycles for nehalem? We have done some calibration on
> real hardware and simulator using lmbench and found out that configuration
> L2 with 6 cycles and L3 (12MB) with 27 cycles matches very well.  Remember
> that in marss cache latency are not flat, meaning that these latency only
> represent delay in accessing cache storage, on top of that each cache
> access has variable dynamic delay of queuing, port access and dependency
> management.
>
> Thanks for pointing out these values, in next release we will release
> 'nehalem' config file that try to model nehalem architecture map some of
> the delays from our study.
>
> - Avadh
>
>>  **
>>
>>          Thanks.****
>>
>> ** **
>>
>> -Yongbing Huang****
>>
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>>
>
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