From: Peter Zijlstra <peterz@infradead.org>
To: Sandipan Das <sandipan.das@amd.com>
Cc: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
x86@kernel.org, bp@alien8.de, acme@kernel.org,
namhyung@kernel.org, jolsa@kernel.org, tglx@linutronix.de,
mingo@redhat.com, mark.rutland@arm.com,
alexander.shishkin@linux.intel.com, dave.hansen@linux.intel.com,
like.xu.linux@gmail.com, Stephane Eranian <eranian@google.com>,
ananth.narayan@amd.com, ravi.bangoria@amd.com,
santosh.shukla@amd.com
Subject: Re: [PATCH 04/13] x86/cpufeatures: Add LbrExtV2 feature bit
Date: Mon, 22 Aug 2022 15:26:56 +0200 [thread overview]
Message-ID: <YwOEIESeDSuekmf8@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <06e9a357-422d-1870-ae72-18e74964caf3@amd.com>
On Mon, Aug 22, 2022 at 06:22:25PM +0530, Sandipan Das wrote:
> AMD LbrExtV2 is similar to Intel LBR. Unlike BRS, LbrExtV2 does not rely on
LbrExtV2 must be the most terrible name ever, please stop using it. Heck
your own code calls it lbr_v2 wherever it can.
So can we please just kill that name entirely?
$ quilt diff --combine - | grep -i lbrext_v2
+ if (x86_pmu.version < 2 || !boot_cpu_has(X86_FEATURE_LBREXT_V2))
+#define X86_FEATURE_LBREXT_V2 ( 3*32+17) /* AMD Last Branch Record Extension Version 2 */
+ { X86_FEATURE_LBREXT_V2, CPUID_EAX, 1, 0x80000022, 0 },
Is the complete usage of this silly name.
> interrupt holding. The branch records are "frozen" at the time of counter
> overflow.
Yes, I get all that. It is also significantly different from Intel LBR
in all details and shares not a single line of code, so also calling it
LBR is confusing at best.
The MSRs are called AMD_SAMPL_BR, so why not call the thing BRS_V2 ?
next prev parent reply other threads:[~2022-08-22 13:27 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-11 12:29 [PATCH 00/13] perf/x86/amd: Add AMD LbrExtV2 support Sandipan Das
2022-08-11 12:29 ` [PATCH 01/13] perf/x86/amd/brs: Move feature-specific functions Sandipan Das
2022-08-11 12:29 ` [PATCH 02/13] perf/x86/amd/core: Refactor branch attributes Sandipan Das
2022-08-11 12:29 ` [PATCH 03/13] perf/x86/amd/core: Add generic branch record interfaces Sandipan Das
2022-08-11 12:29 ` [PATCH 04/13] x86/cpufeatures: Add LbrExtV2 feature bit Sandipan Das
2022-08-11 13:13 ` Borislav Petkov
2022-08-15 11:27 ` Peter Zijlstra
2022-08-15 19:42 ` Stephane Eranian
2022-08-22 9:05 ` Peter Zijlstra
2022-08-22 12:52 ` Sandipan Das
2022-08-22 13:26 ` Peter Zijlstra [this message]
2022-08-23 8:51 ` Sandipan Das
2022-08-25 10:24 ` Peter Zijlstra
2022-08-25 12:26 ` Sandipan Das
2022-08-11 12:29 ` [PATCH 05/13] perf/x86/amd/lbr: Detect LbrExtV2 support Sandipan Das
2022-08-11 12:29 ` [PATCH 06/13] perf/x86/amd/lbr: Add LbrExtV2 branch record support Sandipan Das
2022-08-11 12:29 ` [PATCH 07/13] perf/x86/amd/lbr: Add LbrExtV2 hardware branch filter support Sandipan Das
2022-08-11 12:29 ` [PATCH 08/13] perf/x86: Move branch classifier Sandipan Das
2022-08-11 12:29 ` [PATCH 09/13] perf/x86/amd/lbr: Add LbrExtV2 software branch filter support Sandipan Das
2022-08-11 12:29 ` [PATCH 10/13] perf/x86: Make branch classifier fusion-aware Sandipan Das
2022-08-11 12:29 ` [PATCH 11/13] perf/x86/amd/lbr: Use fusion-aware branch classifier Sandipan Das
2022-08-11 12:30 ` [PATCH 12/13] perf/core: Add speculation info to branch entries Sandipan Das
2022-08-11 12:30 ` [PATCH 13/13] perf/x86/amd/lbr: Add LbrExtV2 branch speculation info support Sandipan Das
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