Hi Gabriel,

Thanks very much for your reply.

Unfortunately, I am using ALPHA which does not have the support for delayed
translation. I am just wondering, is it possible not to make TLB having its
own timing, events etc? I am thinking letting each "mem_req" has its own
state, like you said, if it is a hit in the first half of the TLB, it
proceeds, and if it is a miss, update the state machine inside the "mem_req"
and redo the fetch for the second half of the TLB. Of course the TLB would
direct the search to different halves based on the state of the "mem_req".

Thanks,

On Fri, Oct 21, 2011 at 1:43 AM, Gabriel Michael Black <
[email protected]> wrote:

> The TLBs and CPUs have support for delaying the completion of translation.
> You'd want to delay all the time, and if you're using an ISA that already
> does this (Arm or X86) then you'd decide whether to delay based on the TLB
> access latency in the case of a hit, or waiting for memory in the case of a
> miss. You'd essentially be making the TLB more like a device with an
> internal state machine, timing, and events.
>
> Gabe
>
>
> Quoting Jiachen Xue <[email protected]>:
>
>  Hi,
>>
>> My situation is that I am increasing the size of TLB so that the access to
>> TLB will not fit into one cycle. Say, the TLB can be divided into two
>> parts,
>> each part can be accessed within one cycle. The lookup process now becomes
>> as follows:
>>
>> 1. If fetch hits in the first half, proceed as normals.
>> 2. If miss in the first half, now I need to look into the second half.
>>
>> If I need to look into the second half, from what I understand, I need to
>> schedule a new fetch event in the next cycle. So, is it correct to add
>> something like:
>>
>> cpu->schedule(**finishTranslationEvent, cpu->nextCycle(curTick() +
>> cpu->ticks(1)))
>>
>> as appeared in line 745 in cpu/o3/fetch_impl.hh.
>>
>> Thanks,
>>
>> --
>> Sincerely,
>> Jiachen Xue
>>
>>
>
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-- 
Sincerely,
Jiachen Xue
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