[Barrelfish-users] How to get the wall-clock in Barrelfish?

Zhiquan Lai laizhiquan at gmail.com
Wed Jan 16 07:03:00 CET 2013


Hi Simon,

I have figured out and solved my problem.

I just made a basic mistake.
I defined the base address with type of "int*" (mapped to physical addr of
0xf9008000), and added the offset (0x224) directly when access the memory,
which must target a wrong location (base_addr + sizeof(int) * 0x224).

Thank you very much.
Regards,
Zhiquan

On Tue, Jan 15, 2013 at 3:34 AM, Simon Peter <speter at inf.ethz.ch> wrote:

>  I don't have it in front of me right now, but there should be a file
> named lut_mapping.vi (or similar) in the obj directory that's created
> after you execute bootscc.sh. That has a listing of all default LUT
> mappings and explanations, which should include the one you're looking for.
>
> Simon
>
>
> On 13-01-13 09:20 PM, Zhiquan Lai wrote:
>
> Hi Simon,
>
>  Thanks for your advice.
>
>  Now I am considering what value* should I write into the LUT entry to
> map the clock registers.
>
>  Each LUT entry contains 10 bits for the upper 10 bits in new memory
> address, 8 bits for the tile
> destination ID, 3 bits for the destination sub-ID, and 1 bit for MIU
> bypass.
>
> I still can not find any reference about what should be filled in this
> bits for that clock registers.
>
>  Thanks
> Zhiquan
>
> On Mon, Jan 14, 2013 at 9:26 AM, Simon Peter <speter at inf.ethz.ch> wrote:
>
>>  I have figured out the bug and fixed it*. But the 64 bits read from phy
>>> addr of 0xf9008224 are always be ZERO, rather than the wall-clock ticks
>>> as they said.
>>> Should I need to modify the default LUT to map 0xf9008224 address to the
>>> FPGA clock ? If yes, how to do that ?
>>>
>>
>>  I believe, yes, as we didn't bother to map the FPGA pages we didn't
>> touch and this page might be part of that. You can add a mapping in
>> kernel/arch/scc/rck.c, in rck_init(). Feel free to extend
>> X86_32_DEVICE_SPACE_LIMIT for that (there's no hardware limit).
>>
>> Simon
>>
>
>
>
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