Re: [RFC PATCH] perf: Handle multiple formatted AUX records

[Peter Zijlstra]

On Mon, Jan 25, 2021 at 10:45:06AM +0000, Suzuki K Poulose wrote:
> On 1/25/21 10:25 AM, Peter Zijlstra wrote:

> > Since we have a whole u64, do we want to reserve a whole nibble (or
> > maybe even a byte) for a format type? Because with a single bit like
> > this, we'll kick ourselves when we end up with the need for a 3rd format
> > type.
> > 
> 
> Sure, makes sense. We could do:
> 
> #define PERF_AUX_FLAG_PMU_FORMAT_TYPE_MASK	0xff00
> 
> Additionally, the values could be allocated by individual PMUs and
> interpreted by the corresponding counterpart. That way we don't
> have to worry about centralized allocation of the "TYPE" fields.
> 
> e,g:
> 
> #define PERF_AUX_FLAG_CORESIGHT_FORMAT_CORESIGHT	0x0000
> #define PERF_AUX_FLAG_CORESIGHT_FORMAT_RAW		0x0100
> 
> #define PERF_AUX_FLAG_RANDOM_PMU_FORMAT_FMT1		0x0000
> #define PERF_AUX_FLAG_RANDOM_PMU_FORMAT_FMT2		0x0100
> 
> 
> What do you think ?

Sounds good to me.