linux-kernel - [tip: perf/core] perf/x86: Use event_base_rdpmc for the RDPMC userspace support

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Message-ID: <159782713157.3192.4240252060821627383.tip-bot2@tip-bot2>
Date:   Wed, 19 Aug 2020 08:52:11 -0000
From:   "tip-bot2 for Kan Liang" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Kan Liang <kan.liang@...ux.intel.com>, x86 <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: [tip: perf/core] perf/x86: Use event_base_rdpmc for the RDPMC
 userspace support

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     75608cb02ea5dd997990e2998eca3670cb71a18c
Gitweb:        https://git.kernel.org/tip/75608cb02ea5dd997990e2998eca3670cb71a18c
Author:        Kan Liang <kan.liang@...ux.intel.com>
AuthorDate:    Thu, 23 Jul 2020 10:11:04 -07:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Tue, 18 Aug 2020 16:34:34 +02:00

perf/x86: Use event_base_rdpmc for the RDPMC userspace support

The RDPMC index is always re-calculated for the RDPMC userspace support,
which is unnecessary.

The RDPMC index value is stored in the variable event_base_rdpmc for
the kernel usage, which can be used for RDPMC userspace support as well.

Suggested-by: Peter Zijlstra <peterz@...radead.org>
Signed-off-by: Kan Liang <kan.liang@...ux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Link: https://lkml.kernel.org/r/20200723171117.9918-2-kan.liang@linux.intel.com
---
 arch/x86/events/core.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 1cbf57d..8e108ea 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -2208,17 +2208,12 @@ static void x86_pmu_event_unmapped(struct perf_event *event, struct mm_struct *m
 
 static int x86_pmu_event_idx(struct perf_event *event)
 {
-	int idx = event->hw.idx;
+	struct hw_perf_event *hwc = &event->hw;
 
-	if (!(event->hw.flags & PERF_X86_EVENT_RDPMC_ALLOWED))
+	if (!(hwc->flags & PERF_X86_EVENT_RDPMC_ALLOWED))
 		return 0;
 
-	if (x86_pmu.num_counters_fixed && idx >= INTEL_PMC_IDX_FIXED) {
-		idx -= INTEL_PMC_IDX_FIXED;
-		idx |= 1 << 30;
-	}
-
-	return idx + 1;
+	return hwc->event_base_rdpmc + 1;
 }
 
 static ssize_t get_attr_rdpmc(struct device *cdev,