Re: [PATCH V2 1/6] perf/x86/intel: Add Grand Ridge and Sierra Forest

From: Peter Zijlstra <peterz@infradead.org>
To: "Liang, Kan" <kan.liang@linux.intel.com>
Cc: mingo@redhat.com, acme@kernel.org, linux-kernel@vger.kernel.org,
	mark.rutland@arm.com, alexander.shishkin@linux.intel.com,
	jolsa@kernel.org, namhyung@kernel.org, irogers@google.com,
	adrian.hunter@intel.com, ak@linux.intel.com, eranian@google.com,
	alexey.v.bayduraev@linux.intel.com, tinghao.zhang@intel.com
Subject: Re: [PATCH V2 1/6] perf/x86/intel: Add Grand Ridge and Sierra Forest
Date: Tue, 6 Jun 2023 21:37:12 +0200	[thread overview]
Message-ID: <20230606193712.GY83892@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <ea1c56f9-fc93-ff1e-2102-757e7e9c0dd7@linux.intel.com>

On Tue, Jun 06, 2023 at 02:34:47PM -0400, Liang, Kan wrote:
> 
> 
> On 2023-06-06 2:17 p.m., Peter Zijlstra wrote:
> > On Tue, Jun 06, 2023 at 12:16:29PM -0400, Liang, Kan wrote:
> > 
> >>> names for a reason, so that enums like the above become something
> >>> sensible like:
> >>>
> >>> 	case INTEL_FAM6_ATOM_CRESTMONT:
> >>> 	case INTEL_FAM6_ATOM_CRESTMONT_X:
> >>>
> >>> and now it's super obvious why they're grouped.
> >>>
> >>>>> +		pr_cont("Crestmont events, ");
> >>
> >> The Sierra Forest should not be a platform name. I think it's the code
> >> name of the processor.
> >>
> >> The problem is that the uarch name doesn't work for the hybrid, since it
> >> has different uarchs in the same processors. To make the naming rules
> >> consistent among big core, atom, and hybrid, maybe we should use the
> >> code name of the processor in intel-family.h.
> > 
> > I obviously disagree; these are not hybrid and calling them both
> > CRESTMONT makes *far* more sense than the random gibberish they're
> > called now.
> > 
> > Yes, hybrid made a complete mess of things (in many ways), but we should
> > then not do the obvious correct thing for when we can.
> 
> Besides hybrid, it seems there is a bigger problem for the big core.
> 
> The big core uses the processor code name since Ice Lake. In the perf
> code, we also uses the processor code name for the big core.
> 	pr_cont("Icelake events, ");

Yeah, it's a mess :/ Ideally that would print "Sunny Cove", but I think
there's userspace looking at that string :-(

> Is it OK to leave the big core as is (using processor code name), but
> only change the name for Grand Ridge and Sierra Forest?

Arguably we should also rename ALDERLAKE_N to ATOM_GRACEMONT

We should also do something about that whole hybrid init thing, the
meteorlake stuff is quite a mess as well. Perhaps we can add hybrid_pmu
next to intel_pmu to have a better start in life for x86_pmu.

Anyway, we should really try not to make a bigger mess and try and clean
up where we can.