linux-kernel - [tip: perf/core] perf/x86/amd/uncore: Add PerfMonV2 RDPMC assignments

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Date:   Mon, 13 Jun 2022 08:29:01 -0000
From:   "tip-bot2 for Sandipan Das" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Sandipan Das <sandipan.das@....com>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: perf/core] perf/x86/amd/uncore: Add PerfMonV2 RDPMC assignments

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

Commit-ID:     f0fe9f3c7abcc946a676dfb295478c50312523c2
Gitweb:        https://git.kernel.org/tip/f0fe9f3c7abcc946a676dfb295478c50312523c2
Author:        Sandipan Das <sandipan.das@....com>
AuthorDate:    Thu, 19 May 2022 15:33:34 +05:30
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Mon, 13 Jun 2022 10:15:14 +02:00

perf/x86/amd/uncore: Add PerfMonV2 RDPMC assignments

The current RDPMC assignment scheme maps four DF PMCs and
six L3 PMCs from index 6 to 15.

If AMD Performance Monitoring Version 2 (PerfMonV2) is
supported, there may be additional DF counters available
which are mapped starting from index 16 i.e. just after
the L3 counters. Update the RDPMC assignments accordingly.

Signed-off-by: Sandipan Das <sandipan.das@....com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Link: https://lore.kernel.org/r/1359379ef34da760f108b075ac138ab082caa3ba.1652954372.git.sandipan.das@amd.com
---
 arch/x86/events/amd/uncore.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/x86/events/amd/uncore.c b/arch/x86/events/amd/uncore.c
index ff4238e..d568afc 100644
--- a/arch/x86/events/amd/uncore.c
+++ b/arch/x86/events/amd/uncore.c
@@ -158,6 +158,16 @@ out:
 	hwc->event_base_rdpmc = uncore->rdpmc_base + hwc->idx;
 	hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED;
 
+	/*
+	 * The first four DF counters are accessible via RDPMC index 6 to 9
+	 * followed by the L3 counters from index 10 to 15. For processors
+	 * with more than four DF counters, the DF RDPMC assignments become
+	 * discontiguous as the additional counters are accessible starting
+	 * from index 16.
+	 */
+	if (is_nb_event(event) && hwc->idx >= NUM_COUNTERS_NB)
+		hwc->event_base_rdpmc += NUM_COUNTERS_L3;
+
 	if (flags & PERF_EF_START)
 		amd_uncore_start(event, PERF_EF_RELOAD);