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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