On Mon, Oct 24, 2011 at 8:05 AM, sparsh mittal <[email protected]>wrote:
> Hello
> See my code and output generated:
> Purpose: To see the range of addresses passed to L2 cache.
> Code1: First, In logic.h, AssociativeArray, probe function, I added:
>
> V* probe(int coreID, T addr)
> {
> float addrInGB = (float)addr/(float)(1024*1024*1024);
> if (isL2)
> {
> * count_address_range*(addr);
> if(addrInGB > 4.5)
> std::cout<<" coreID = "<<coreID<<" addr = "<<addr<<" addr in GB
> "<<addrInGB<<"GB "<<"\n";
> }
> .....
> }
> =====================
> Code2:
> int range_[10];
> void *count_address_range*(W64 addr)
> {
> // int range[10];
> float addGB = (float)addr /(float) (1024*1024*1024);
>
> if(addGB < 0.5)
> range_[0]++ ;
> else if (addGB<1.0)
> range_[1]++;
> else if (addGB<1.5)
> range_[2]++;
> else if (addGB<2)
> range_[3]++;
> else if (addGB<2.5)
> range_[4]++;
> else if (addGB<3.0)
> range_[5]++;
> else if (addGB<3.5)
> range_[6]++;
> else if (addGB<4.0)
> range_[7]++;
> else if (addGB<4.5)
> range_[8]++;
> else
> range_[9]++;
> }
> ===============
> At the end of simulation, I printed the range_[] variable.
> Now I ran it. Here is the output for -stopinsns 100000000.
> ========================================
> Simulator is now waiting for a 'run' command.
>
> coreID = 0 addr = 18446744073709551615 addr in GB 1.71799e+10GB
> coreID = 1 addr = 18446744073709551615 addr in GB 1.71799e+10GB
> coreID = 3 addr = 18446744073709551615 addr in GB 1.71799e+10GB
> coreID = 2 addr = 18446744073709551615 addr in GB 1.71799e+10GB
>
>
> index 0 6256
> index 1 8890
> index 2 0
> index 3 0
> index 4 0
> index 5 0
> index 6 0
> index 7 0
> index 8 2034
> index 9 4
> ================================
>
> 1. How about this strange address which is e+10 GB?
>
I think the reason might be because of MMIO is still processed via regular
memory hierarchy access. To simulate some delay in MMIO currently we simply
let it pass through the cache subsystem as we dont store data in caches it
doesn't affect IO correctness. To fix this, we need to add a MMIO interface
to BaseMachine class and allow users to configure MMIO access delay via
config files.
> 2. I have observed that the addresses are either <1GB or >4GB. I have not
> seen any address in-between 1&4GB. Strange!
>
Does your benchmark/kernel application have huge memory footprint? Have you
tested your benchmark in real machine to see how many pages does it access?
- Avadh
Sparsh
>
> On Mon, Oct 24, 2011 at 1:47 AM, DRAM Ninjas <[email protected]> wrote:
>
>> I believe this is the result of how QEMU allocates simulated physical
>> memory. It puts a hole between 3.5GB and 4.0GB and moves the missing 500MB
>> above 4.0GB in order to accomodate memory mapped IO (or else something that
>> I don't understand) into that hole.
>>
>> In other words, for a 4GB memory system, the usable space would be 0-3.5GB
>> and 4.0GB-4.5GB. I believe what we do in DRAMSim is just to subtract off the
>> hole to properly map the request to the proper place.
>>
>> On Sun, Oct 23, 2011 at 4:54 PM, sparsh mittal
>> <[email protected]>wrote:
>>
>>> Hello
>>> Here is the result of printing in logic.h, the class is AssociativeArray:
>>> V* probe(T addr)
>>> {
>>> float addrInGB = (float)addr/(float)(1024*1024*1024);
>>> if (isL2 )
>>> {
>>>
>>> std::cout<<" addr = "<<addr<<" addr in GB "<<addrInGB<<"GB "<<"\n";
>>> }
>>>
>>> .....
>>> }
>>>
>>> I have added isL2 variable, to print the addresses for only L2 cache.
>>>
>>> addr = 16785400 addr in GB 0.0156326GB
>>> * addr = 4808179704 addr in GB 4.47797GB
>>> ............
>>> addr = 4808179704 addr in GB 4.47797GB*
>>> addr = 16793584 addr in GB 0.0156402GB
>>> ...
>>> addr = 4808177792 addr in GB 4.47796GB
>>> addr = 51168 addr in GB 4.76539e-05GB
>>> addr = 16804352 addr in GB 0.0156503GB
>>> addr = 16902064 addr in GB 0.0157413GB
>>>
>>> addr = 16902088 addr in GB 0.0157413GB
>>> addr = 4824080080 addr in GB 4.49277GB
>>>
>>> I did -m 4G. I am compiling with c=4.
>>> I am surprised, that the addr goes more than 4GB, although I have never
>>> seen any error of 'address out of bounds'.
>>>
>>> Do you know how it is possible?
>>>
>>>
>>> Thanks and Regards
>>> Sparsh Mittal
>>>
>>> _______________________________________________
>>> http://www.marss86.org
>>> Marss86-Devel mailing list
>>> [email protected]
>>> https://www.cs.binghamton.edu/mailman/listinfo/marss86-devel
>>>
>>>
>>
>
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