[PATCH V2 4/4] perf vendor events: Add JSON metrics for imx8mp DDR Perf

[John Garry]

> 
> 
>>> +	   "MetricName": "imx8mp_ddr_read.isp1",
>>> +	   "MetricExpr":
>>> +"imx8_ddr0 at axid\\-read\\,axi_mask\\=0x0000\\,axi_id\\=0x006d@",
>> eh, does this really even qualify as a "metric"? Seems only a single event...
> Yes, actually it needs a single metric. I consult to Will before, there is no way to program it in the kernel. I also don't want users to enter a long
> command line, what worst is that users need find out the AXI ID for each master. If we put it in the metric, it is more friendly. Is it reasonable that
> a single metric could be regarded as a special metric? Such as "( imx8_ddr0 at axid\\-read\\,axi_mask\\=0x0000\\,axi_id\\=0x006d@ ) * 1 * 1".
> 

ok, fine - I don't see a point in being pedantic, and we should try to 
enhance the user experience (like here).

Maybe in future we could consider a different class of event, like this.

> 
>>> +	   "ScaleUnit": "9.765625e-4KB",
>>> +	   "Unit": "imx8_ddr",
>>> +	   "Compat": "i.MX8MP"
>>> +   },
>>> +   {
>>> +	   "BriefDescription": "bytes of display isp1 write to ddr",
>>> +	   "MetricName": "imx8mp_ddr_write.isp1",
>>> +	   "MetricExpr":
>> "imx8_ddr0 at axid\\-write\\,axi_mask\\=0x0000\\,axi_id\\=0x006d@",
>>> +	   "MetricGroup": "imx8_ddr_DDR_MON",
>>> +	   "Unit": "imx8_ddr",
>> why no scale unit here?
> I will add it. Thanks.
> 
> 
>>> +	   "Compat": "i.MX8MP"
>> btw, not sure if Arnaldo is ok with you not cc'ing other guys mentioned in
>> "performance events subsystem" or "performance events tooling arm64"..
> OK, I will cc them next version. Thanks for your kindly review.

I'll have another look today at the rest of the series.

John