linux-kernel - [tip: perf/core] perf/x86/intel/uncore: Fix the scale of the IMC free-running events

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Message-ID: <160149233284.7002.14214628011336778470.tip-bot2@tip-bot2>
Date:   Wed, 30 Sep 2020 18:58:52 -0000
From:   "tip-bot2 for Kan Liang" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Kan Liang <kan.liang@...ux.intel.com>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        x86 <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>
Subject: [tip: perf/core] perf/x86/intel/uncore: Fix the scale of the IMC
 free-running events

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

Commit-ID:     8191016a026b8dfbb14dea64efc8e723ee99fe65
Gitweb:        https://git.kernel.org/tip/8191016a026b8dfbb14dea64efc8e723ee99fe65
Author:        Kan Liang <kan.liang@...ux.intel.com>
AuthorDate:    Mon, 28 Sep 2020 06:32:40 -07:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Tue, 29 Sep 2020 09:57:02 +02:00

perf/x86/intel/uncore: Fix the scale of the IMC free-running events

The "MiB" result of the IMC free-running bandwidth events,
uncore_imc_free_running/read/ and uncore_imc_free_running/write/ are 16
times too small.

The "MiB" value equals the raw IMC free-running bandwidth counter value
times a "scale" which is inaccurate.

The IMC free-running bandwidth events should be incremented per 64B
cache line, not DWs (4 bytes). The "scale" should be 6.103515625e-5.
Fix the "scale" for both Snow Ridge and Ice Lake.

Fixes: 2b3b76b5ec67 ("perf/x86/intel/uncore: Add Ice Lake server uncore support")
Fixes: ee49532b38dd ("perf/x86/intel/uncore: Add IMC uncore support for Snow Ridge")
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/20200928133240.12977-1-kan.liang@linux.intel.com
---
 arch/x86/events/intel/uncore_snbep.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c
index 3f1e75f..7bdb182 100644
--- a/arch/x86/events/intel/uncore_snbep.c
+++ b/arch/x86/events/intel/uncore_snbep.c
@@ -4807,10 +4807,10 @@ static struct uncore_event_desc snr_uncore_imc_freerunning_events[] = {
 	INTEL_UNCORE_EVENT_DESC(dclk,		"event=0xff,umask=0x10"),
 
 	INTEL_UNCORE_EVENT_DESC(read,		"event=0xff,umask=0x20"),
-	INTEL_UNCORE_EVENT_DESC(read.scale,	"3.814697266e-6"),
+	INTEL_UNCORE_EVENT_DESC(read.scale,	"6.103515625e-5"),
 	INTEL_UNCORE_EVENT_DESC(read.unit,	"MiB"),
 	INTEL_UNCORE_EVENT_DESC(write,		"event=0xff,umask=0x21"),
-	INTEL_UNCORE_EVENT_DESC(write.scale,	"3.814697266e-6"),
+	INTEL_UNCORE_EVENT_DESC(write.scale,	"6.103515625e-5"),
 	INTEL_UNCORE_EVENT_DESC(write.unit,	"MiB"),
 	{ /* end: all zeroes */ },
 };
@@ -5268,17 +5268,17 @@ static struct uncore_event_desc icx_uncore_imc_freerunning_events[] = {
 	INTEL_UNCORE_EVENT_DESC(dclk,			"event=0xff,umask=0x10"),
 
 	INTEL_UNCORE_EVENT_DESC(read,			"event=0xff,umask=0x20"),
-	INTEL_UNCORE_EVENT_DESC(read.scale,		"3.814697266e-6"),
+	INTEL_UNCORE_EVENT_DESC(read.scale,		"6.103515625e-5"),
 	INTEL_UNCORE_EVENT_DESC(read.unit,		"MiB"),
 	INTEL_UNCORE_EVENT_DESC(write,			"event=0xff,umask=0x21"),
-	INTEL_UNCORE_EVENT_DESC(write.scale,		"3.814697266e-6"),
+	INTEL_UNCORE_EVENT_DESC(write.scale,		"6.103515625e-5"),
 	INTEL_UNCORE_EVENT_DESC(write.unit,		"MiB"),
 
 	INTEL_UNCORE_EVENT_DESC(ddrt_read,		"event=0xff,umask=0x30"),
-	INTEL_UNCORE_EVENT_DESC(ddrt_read.scale,	"3.814697266e-6"),
+	INTEL_UNCORE_EVENT_DESC(ddrt_read.scale,	"6.103515625e-5"),
 	INTEL_UNCORE_EVENT_DESC(ddrt_read.unit,		"MiB"),
 	INTEL_UNCORE_EVENT_DESC(ddrt_write,		"event=0xff,umask=0x31"),
-	INTEL_UNCORE_EVENT_DESC(ddrt_write.scale,	"3.814697266e-6"),
+	INTEL_UNCORE_EVENT_DESC(ddrt_write.scale,	"6.103515625e-5"),
 	INTEL_UNCORE_EVENT_DESC(ddrt_write.unit,	"MiB"),
 	{ /* end: all zeroes */ },
 };