From: Peter Zijlstra <peterz@infradead.org>
To: Dave Hansen <dave.hansen@intel.com>
Cc: linux-kernel@vger.kernel.org,
Kan Liang <kan.liang@linux.intel.com>, x86 <x86@kernel.org>
Subject: Re: [tip: perf/core] x86/cpufeatures: Add Architectural LBRs feature bit
Date: Fri, 10 Jul 2020 11:51:44 +0200 [thread overview]
Message-ID: <20200710095144.GC4800@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <e231263a-76f8-326a-ae47-0ae785137c9a@intel.com>
On Thu, Jul 09, 2020 at 04:00:48PM -0700, Dave Hansen wrote:
> On 7/8/20 2:51 AM, tip-bot2 for Kan Liang wrote:
> > diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
> > index 02dabc9..72ba4c5 100644
> > --- a/arch/x86/include/asm/cpufeatures.h
> > +++ b/arch/x86/include/asm/cpufeatures.h
> > @@ -366,6 +366,7 @@
> > #define X86_FEATURE_MD_CLEAR (18*32+10) /* VERW clears CPU buffers */
> > #define X86_FEATURE_TSX_FORCE_ABORT (18*32+13) /* "" TSX_FORCE_ABORT */
> > #define X86_FEATURE_PCONFIG (18*32+18) /* Intel PCONFIG */
> > +#define X86_FEATURE_ARCH_LBR (18*32+19) /* Intel ARCH LBR */
> > #define X86_FEATURE_SPEC_CTRL (18*32+26) /* "" Speculation Control (IBRS + IBPB) */
> > #define X86_FEATURE_INTEL_STIBP (18*32+27) /* "" Single Thread Indirect Branch Predictors */
> > #define X86_FEATURE_FLUSH_L1D (18*32+28) /* Flush L1D cache */
>
> Are architectural LBRs useful *without* XSAVE? If not, should we add an
> entry in arch/x86/kernel/cpu/cpuid-deps.c::cpuid_deps[] for this?
Yes, look at patch 22, without the XSAVE thing it'll fall back to poking
at MSRs lots.
next prev parent reply other threads:[~2020-07-10 9:51 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-03 12:49 [PATCH V3 00/23] Support Architectural LBR kan.liang
2020-07-03 12:49 ` [PATCH V3 01/23] x86/cpufeatures: Add Architectural LBRs feature bit kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-09 23:00 ` Dave Hansen
2020-07-10 9:51 ` Peter Zijlstra [this message]
2020-07-10 14:09 ` Liang, Kan
2020-07-03 12:49 ` [PATCH V3 02/23] perf/x86/intel/lbr: Add a function pointer for LBR reset kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 03/23] perf/x86/intel/lbr: Add a function pointer for LBR read kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 04/23] perf/x86/intel/lbr: Add the function pointers for LBR save and restore kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 05/23] perf/x86/intel/lbr: Factor out a new struct for generic optimization kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 06/23] perf/x86/intel/lbr: Use dynamic data structure for task_ctx kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 07/23] x86/msr-index: Add bunch of MSRs for Arch LBR kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 08/23] perf/x86: Expose CPUID enumeration bits for arch LBR kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 09/23] perf/x86/intel/lbr: Support LBR_CTL kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 10/23] perf/x86/intel/lbr: Unify the stored format of LBR information kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 11/23] perf/x86/intel/lbr: Mark the {rd,wr}lbr_{to,from} wrappers __always_inline kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 12/23] perf/x86/intel/lbr: Factor out rdlbr_all() and wrlbr_all() kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 13/23] perf/x86/intel/lbr: Factor out intel_pmu_store_lbr kan.liang
2020-07-03 19:50 ` Peter Zijlstra
2020-07-03 20:59 ` Liang, Kan
2020-07-06 10:25 ` Peter Zijlstra
2020-07-06 13:32 ` Liang, Kan
2020-07-06 14:25 ` Peter Zijlstra
2020-07-06 22:29 ` Liang, Kan
2020-07-07 7:40 ` Peter Zijlstra
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 14/23] perf/x86/intel/lbr: Support Architectural LBR kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 15/23] perf/core: Factor out functions to allocate/free the task_ctx_data kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 16/23] perf/core: Use kmem_cache to allocate the PMU specific data kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 17/23] perf/x86/intel/lbr: Create kmem_cache for the LBR context data kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 18/23] perf/x86: Remove task_ctx_size kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 19/23] x86/fpu: Use proper mask to replace full instruction mask kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 20/23] x86/fpu/xstate: Support dynamic supervisor feature for LBR kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2021-05-27 22:15 ` Thomas Gleixner
2020-07-03 12:49 ` [PATCH V3 21/23] x86/fpu/xstate: Add helpers for LBR dynamic supervisor feature kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 22/23] perf/x86/intel/lbr: Support XSAVES/XRSTORS for LBR context switch kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 12:49 ` [PATCH V3 23/23] perf/x86/intel/lbr: Support XSAVES for arch LBR read kan.liang
2020-07-08 9:51 ` [tip: perf/core] " tip-bot2 for Kan Liang
2020-07-03 19:34 ` [PATCH V3 00/23] Support Architectural LBR Peter Zijlstra
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