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From: Peter Zijlstra <peterz@infradead.org>
To: Song Liu <songliubraving@fb.com>
Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
	acme@kernel.org, mingo@redhat.com, kjain@linux.ibm.com,
	kernel-team@fb.com, John Fastabend <john.fastabend@gmail.com>,
	Andrii Nakryiko <andrii@kernel.org>
Subject: Re: [PATCH v6 bpf-next 1/3] perf: enable branch record for software events
Date: Fri, 10 Sep 2021 15:54:03 +0200	[thread overview]
Message-ID: <YTtjeyfJXXiDielu@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <YTs2MpaI7iofckJI@hirez.programming.kicks-ass.net>

On Fri, Sep 10, 2021 at 12:40:51PM +0200, Peter Zijlstra wrote:

> The below seems to cure that.

Seems I lost a hunk, fold below.

diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c
index 9e6d6eaeb4cb..6b72e9b55c69 100644
--- a/arch/x86/events/intel/lbr.c
+++ b/arch/x86/events/intel/lbr.c
@@ -228,20 +228,6 @@ static void __intel_pmu_lbr_enable(bool pmi)
 		wrmsrl(MSR_ARCH_LBR_CTL, lbr_select | ARCH_LBR_CTL_LBREN);
 }
 
-static void __intel_pmu_lbr_disable(void)
-{
-	u64 debugctl;
-
-	if (static_cpu_has(X86_FEATURE_ARCH_LBR)) {
-		wrmsrl(MSR_ARCH_LBR_CTL, 0);
-		return;
-	}
-
-	rdmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
-	debugctl &= ~(DEBUGCTLMSR_LBR | DEBUGCTLMSR_FREEZE_LBRS_ON_PMI);
-	wrmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
-}
-
 void intel_pmu_lbr_reset_32(void)
 {
 	int i;
@@ -779,8 +765,12 @@ void intel_pmu_lbr_disable_all(void)
 {
 	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
 
-	if (cpuc->lbr_users && !vlbr_exclude_host())
+	if (cpuc->lbr_users && !vlbr_exclude_host()) {
+		if (static_cpu_has(X86_FEATURE_ARCH_LBR))
+			return __intel_pmu_arch_lbr_disable();
+
 		__intel_pmu_lbr_disable();
+	}
 }
 
 void intel_pmu_lbr_read_32(struct cpu_hw_events *cpuc)

  reply	other threads:[~2021-09-10 13:55 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-07 20:27 [PATCH v6 bpf-next 0/3] bpf: introduce bpf_get_branch_snapshot Song Liu
2021-09-07 20:28 ` [PATCH v6 bpf-next 1/3] perf: enable branch record for software events Song Liu
2021-09-10 10:40   ` Peter Zijlstra
2021-09-10 13:54     ` Peter Zijlstra [this message]
2021-09-10 18:27       ` Song Liu
2021-09-10 18:40         ` Peter Zijlstra
2021-09-10 18:50           ` Peter Zijlstra
2021-09-10 19:00             ` Song Liu
2021-09-10 19:08               ` Peter Zijlstra
2021-09-10 19:11                 ` Song Liu
2021-09-10 18:51           ` Song Liu
2021-09-07 20:28 ` [PATCH v6 bpf-next 2/3] bpf: introduce helper bpf_get_branch_snapshot Song Liu
2021-09-07 20:28 ` [PATCH v6 bpf-next 3/3] selftests/bpf: add test for bpf_get_branch_snapshot Song Liu
2021-09-07 20:29 ` [PATCH v6 bpf-next 0/3] bpf: introduce bpf_get_branch_snapshot Song Liu
2021-09-07 20:58   ` Andrii Nakryiko
2021-09-09 21:53   ` Song Liu

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