[Mesa-dev] [PATCH 08/11] i965: perf: snapshot RPSTAT1 register

[Lionel Landwerlin]

On 08/03/18 17:00, Chris Wilson wrote:
> Quoting Lionel Landwerlin (2018-03-08 15:42:53)
>> +static void
>> +read_gt_frequency(struct brw_context *brw,
>> +                  struct brw_perf_query_object *obj)
>> +{
>> +   const struct gen_device_info *devinfo = &brw->screen->devinfo;
>> +   uint32_t *start_reg = obj->oa.map + MI_FREQ_START_OFFSET_BYTES,
>> +      *end_reg = obj->oa.map + MI_FREQ_END_OFFSET_BYTES;
>> +
>> +   switch (devinfo->gen) {
>> +   case 7:
>> +   case 8:
>> +      obj->oa.gt_frequency[0] =
>> +         ((start_reg[0] & GEN6_RPSTAT1_CURR_GT_FREQ_MASK) >>
>> +          GEN6_RPSTAT1_CURR_GT_FREQ_SHIFT) * 50ULL;
>> +      obj->oa.gt_frequency[1] =
>> +         ((end_reg[0] & GEN6_RPSTAT1_CURR_GT_FREQ_MASK) >>
>> +          GEN6_RPSTAT1_CURR_GT_FREQ_SHIFT) * 50ULL;
> I was just thinking this was the wrong frequency conversion for byt/bsw,
> but then they don't have RPSTAT1 either. Is the OA only for big core?

I think you found a bug!

I can see in the internal documentation that CHV has RPSTAT1, except it 
doesn't have the fields we want.
So this needs to be dealt with/fixed.

On BXT I got sensible numbers from this register, so that leaves gen8 
based small cores in the unknown...
Documentation is again unhelpful...

Thanks,

-
Lionel