I also came across this post:
https://groups.google.com/forum/#!msg/gem5-gpu-dev/zBUXxv65H_k/n7Q5pGtJ4VUJ 
<https://groups.google.com/forum/#!msg/gem5-gpu-dev/zBUXxv65H_k/n7Q5pGtJ4VUJ>

which says that "system.mem_ctrls, bytes_read, bytes_written, num_reads, 
num_writes, etc.. These actually measure the total memory accesses from each of 
the different requesters ». And they claimed that 
system.ruby.dir_cntrl0.memBuffer is the number to look at. I’m quite confused...

Cheers,
Tim
> Le Feb 24, 2016 à 12:12 PM, Timothy Chong <[email protected]> a écrit :
> 
> Hi Andreas,
> 
> Thank you for the response. I believe ruby has it’s own memory hierarchy, 
> which overrides the original memory controller. I quickly looked at 
> bytesReadDRAM, but it has a value of 0, which I assume is because the 
> traffic’s directed somewhere else. But I’m still confused by the difference 
> between mem_ctrls.num_read and system.ruby_cntrl0.memBuffer.memReads. The 
> latter is the numberReads that go into the directory and then to the memory 
> controller (as I can tell after I dug deep into the code). I don’t really 
> know what mem_ctrls.num_read includes. All memory traffic to memory 
> controller?
> 
> Would mem_ctrls.num_reads * cache line size be the same as the bytesReadDRAM, 
> since shouldn’t all the « mem_ctrls.num_reads » be going into the memory 
> controller?
> 
> Thanks,
> Tim
> 
>> Le Feb 24, 2016 à 3:04 AM, Andreas Hansson <[email protected]> a écrit 
>> :
>> 
>> Hi Timothy,
>> 
>> I do not use Ruby myself, so I do not dare say what the memBuffer stats
>> represent. The num_read and num_write stats for the memory controller are
>> just that, how many read requests and how many write requests have
>> accessed the memory. They are in fact from AbstractMemory. If you run with
>> the proper DRAMCtrl I would instead suggest to look at the actual DRAM
>> accesses (bytesReadDRAM and similar).
>> 
>> Also remember that there may be many channels of DRAM, so you have to look
>> at the stats across all the mem_ctrl instances.
>> 
>> Andreas
>> 
>> On 24/02/2016, 04:21, "gem5-users on behalf of Timothy Chong"
>> <[email protected] on behalf of [email protected]> wrote:
>> 
>>> Hello there,
>>> 
>>> I’ve been running FS with ruby. I would like to see the statistics of
>>> memory access to the memory controller.
>>> 
>>> I was a little confused by the different mem read numbers.
>>> 
>>> Specifically, there’s the mem_ctrls.num_read, which is broken down to
>>> inst, data, dtb.walker, and itbwalker. It says mem_ctrls, so I sort of
>>> assumed that it is for the memory controller access.
>>> 
>>> However, when I looked more into the statistics, I also found
>>> system.ruby_cntrl0.memBuffer.memReads, which are MUCH lower than the
>>> numbers for mem_ctrls.num_read.
>>> 
>>> Which one is the read/write access into he memory controller? And what
>>> exactly is mem_ctrls.num_read and the broken down statistics?
>>> 
>>> Thank you,
>>> Timothy Chong
>>> _______________________________________________
>>> gem5-users mailing list
>>> [email protected]
>>> http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users
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