@stever
I remembered u told me once that the addresses coming to the
different levels of cache are physical only. I asked at that time regarding
prefetching.
On Wed, Aug 17, 2011 at 9:36 PM, Steve Reinhardt <[email protected]> wrote:
>
>
> On Wed, Aug 17, 2011 at 8:55 AM, Stevenson Jian
> <[email protected]>wrote:
>
>> Oh I see, _paddr and _vaddr are for instruction fetches, while _pc is for
>> regular loads and stores.
>
>
> More accurately, _paddr and _vaddr are always valid and indicate the
> address being accessed, while _pc is really only for loads and stores.
>
>
>> Can someone confirm for me whether for a packet accessing the cache,
>> packet->request->getPC() returns a physical address or virtual address of
>> the instruction that is making the load/store? How would I verify which one
>> it is?
>
>
> I'd guess it's virtual, but you'd have to look at the code and see where it
> gets set to verify.
>
>
>> If it returns a virtual address, how do I translate the virtual address to
>> a physical address in m5?
>
>
> I think it depends on whether you're in SE or FS mode... not that I
> remember the exact call in either case.
>
> Steve
>
>
>> Thanks,
>> Steve
>>
>>
>> On Wed, Aug 17, 2011 at 12:43 AM, Steve Reinhardt <[email protected]>wrote:
>>
>>> For loads and stores, the pc is obviously not related to the vaddr or
>>> paddr.
>>>
>>> For instruction fetches, you're probably best off just ignoring the pc;
>>> the only reason it's there is because the same packet structure is shared
>>> between fetches and loads/stores.
>>>
>>> Steve
>>>
>>>
>>> On Tue, Aug 16, 2011 at 9:43 PM, Stevenson Jian <[email protected]
>>> > wrote:
>>>
>>>> Hi,
>>>> Looking at src/mem/request.hh, I see that there are the following 3
>>>> methods: getPC(), getPaddr(), and getVaddr(); The description of each are
>>>> given in the following:
>>>> _pc: program counter of initiating access; for tracing/debugging
>>>> _paddr: The physical address of the request.
>>>> _vaddr: The virtual address of the request.
>>>>
>>>> So what exactly is _pc? If _pc holds the virtual address to the
>>>> instruction sending out the request to access the cache, then it should be
>>>> equal to _vaddr. If _pc holds the physical address to the instruction
>>>> sending out the request to access the cache, then it should be equal to
>>>> _paddr. I am confused why there are 3 of them, pc, paddr, and vaddr, since
>>>> one of them has to be a repeat...
>>>> Thanks,
>>>> Steve
>>>>
>>>> On Tue, Aug 16, 2011 at 8:14 PM, <[email protected]> wrote:
>>>>
>>>>> If I remember it correctly, the addresses exposed to cache modules are
>>>>> all physical addresses.
>>>>>
>>>>> Leonard
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On , Stevenson Jian <[email protected]> wrote:
>>>>> > Hi,I would like to trace the physical address of the instruction that
>>>>> is accessing the cache. I see that there is in the packet going from the
>>>>> CPU
>>>>> to the cache there is the PacketPtr->getPC() method. I assume that this is
>>>>> the virtual address of the instruction reading the cache. However, what
>>>>> would be the best way to go about getting the physical address of the
>>>>> instruction accessing the cache?
>>>>> >
>>>>> > Thanks a lot of your help,
>>>>> > Steve
>>>>> >
>>>>>
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