How to read out predicter value? about nvbit HOT 8 OPEN

You can use nvbit_read_pred_reg() to read predicate registers. Also you need to include nvbit_reg_rw.h file in your injection function file.

from nvbit.

how to index the pred reg with this api ?the general reg rw api can be set with reg index

from nvbit.

extern "C" __device__ __noinline__ int32_t nvbit_read_pred_reg() {
#pragma unroll
    for (int i = 0; i < 32; i++) __nvbit_var += i;
    return __nvbit_var;
}

The definition of this api is as above. how to parse the result?
Like if I want to read what the current status for P5, whether it is true or not, how should I deal wtih the return value?

from nvbit.

It reads out the entire predicate register and only the lower 8 bits ([P7 .. P0]) are used.

from nvbit.

I try to add the code, but read out as 0...
I test it over 2080ti.

from nvbit.

If the predicate register is not used in the code or is set to 0, the result will be 0.

from nvbit.

I try to add the code, but read out as 0...
I test it over 2080ti.

hi dear @leiwen83
I'm also interested in this nvbit_read_pred_reg() function. but how can you display the values of this function, I try to print the values, but there is an error here,

thank you
best regards
William

from nvbit.

It is a device function and should be called only in your instrumentation functions in the inject_func.cu file.

from nvbit.