One more thing
If there are SimpleMemory and AbstractMemory models, why there is only
one py file AbstractMemory.py?

On 5/13/12, Tao Zhang <[email protected]> wrote:
> Hi Mahmood,
>
> The SimpleMemory extends the AbstractMemory and is used in the latest
> version of gem5. It just generates a random memory latency rather than
> cycle-accurate simulation. In my opinion, it can NOT be used at all due
> to the inaccuracy. Alternatively, you can use the DRAMSim2 patch in an
> old version. Or, you may improve the simple memory model to get more
> confidence.
>
> "/...The bottom line: unless you are working with simple systems, you
> can no longer fake the memory system in your performance simulations
> (i.e., you cannot use a simplistic model), because doing so is
> guaranteed to produce garbage in, garbage out results.../" from Bruce
> Jacob, <The memory systems: you can't avoid it, you can't ignore it, you
> can't fake it>
>
> Tao
>
> On 05/13/2012 02:56 PM, Mahmood Naderan wrote:
>> the PhysicalMemory is now called AbstractMemory
>>
>> The DRAM model was a definition like this:
>> class DRAMMemory(PhysicalMemory):
>>      type = 'DRAMMemory'
>>      # Many of these should be observed from the configuration
>>      cpu_ratio = Param.Int(5,"ratio between CPU speed and memory bus
>> speed")
>>      mem_type = Param.String("SDRAM", "Type of DRAM (DRDRAM, SDRAM)")
>>      mem_actpolicy = Param.String("open", "Open/Close policy")
>>      memctrladdr_type = Param.String("interleaved", "Mapping
>> interleaved or direct")
>>      bus_width = Param.Int(16, "")
>>      act_lat = Param.Latency("2ns", "RAS to CAS delay")
>>      cas_lat = Param.Latency("1ns", "CAS delay")
>>      war_lat = Param.Latency("2ns", "write after read delay")
>>      pre_lat = Param.Latency("2ns", "precharge delay")
>>      dpl_lat = Param.Latency("2ns", "data in to precharge delay")
>>      trc_lat = Param.Latency("6ns", "row cycle delay")
>>      num_banks = Param.Int(4, "Number of Banks")
>>      num_cpus = Param.Int(4, "Number of CPUs connected to DRAM")
>>
>> But seems that it has been removed. So it is no longer possible to set
>> some DRAM parameters.
>>
>> On 5/13/12, Tao Zhang<[email protected]>  wrote:
>>> They have been replaced with "abstract_mem.cc" and "simple_mem.cc".
>>>
>>> -Tao
>>>
>>> On 05/13/2012 01:13 PM, Mahmood Naderan wrote:
>>>> Hi
>>>> There were some physicalmemory.py , dram.cc and dram.hh files in
>>>> previous releases. But seems that they are no longer available.
>>>>
>>>> Appreciate any comment.
>>> _______________________________________________
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>>>
>>
>


-- 
// Naderan *Mahmood;
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