Re: Enable/disable hardware prefetcher via Oprofile

On 06/04/2015 02:19 PM, Mahmood N wrote:
>> msr-tools should work on both
> 
> It seems that ./wrmsr gets a binary value but I am not sure about that
> 
> [root@tiger msr-tools-master]# ./wrmsr -p 0 0xc0011022 1000
> [root@tiger msr-tools-master]# ./rdmsr -p 0 -d -0 0xc0011022
> 00000000000000000008
> [root@tiger msr-tools-master]# ./wrmsr -p 0 0xc0011022 10000
> [root@tiger msr-tools-master]# ./rdmsr -p 0 -d -0 0xc0011022
> 00000000000000009232
> 
> I expected to see 16 because the decimal value of 10000b is 16.
> Looking through the code (wrmsr.c) however it get integer values
> 
> 
>  
> Regards,
> Mahmood
> 
> 
> 
> 
> 

Hi Mahmood,

It might be useful to use the rdmsr -x option to see what the values are in the msr and pass things in to wrmsr as hexidecimal values. wrmsr is interpreting the values above as decimal, use form 0x[0-9a-f]+.  Unlike general registers it is likely that some bits in msr registers might be fixed to be 1 or 0 when read.  According to the BIOS manual there are a number of reserved bits in that particular MSR.

-Will

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