[tip:perf/core] perf/x86/intel/pebs: Add PEBS frontend profiling for Skylake

From: tip-bot for Andi Kleen
Date: Fri Sep 18 2015 - 04:47:14 EST


Commit-ID: d0dc8494cd6904f8ad035d9ad97f313948f35d0c
Gitweb: http://git.kernel.org/tip/d0dc8494cd6904f8ad035d9ad97f313948f35d0c
Author: Andi Kleen <ak@xxxxxxxxxxxxxxx>
AuthorDate: Wed, 9 Sep 2015 14:53:59 -0700
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 18 Sep 2015 09:20:22 +0200

perf/x86/intel/pebs: Add PEBS frontend profiling for Skylake

Skylake has a new FRONTEND_LATENCY PEBS event to accurately profile
frontend problems (like ITLB or decoding issues).

The new event is configured through a separate MSR, which selects
a range of sub events.

Define the extra MSR as a extra reg and export support for it
through sysfs. To avoid duplicating the existing
tables use a new function to add new entries to existing tables.

Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Acked-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1435707205-6676-4-git-send-email-andi@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/include/asm/msr-index.h | 2 ++
arch/x86/kernel/cpu/perf_event.h | 1 +
arch/x86/kernel/cpu/perf_event_intel.c | 11 ++++++++++-
3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index c1c0a1c..54390bc 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -141,6 +141,8 @@
#define DEBUGCTLMSR_BTS_OFF_USR (1UL << 10)
#define DEBUGCTLMSR_FREEZE_LBRS_ON_PMI (1UL << 11)

+#define MSR_PEBS_FRONTEND 0x000003f7
+
#define MSR_IA32_POWER_CTL 0x000001fc

#define MSR_IA32_MC0_CTL 0x00000400
diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
index 5edf6d8..165be83 100644
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -47,6 +47,7 @@ enum extra_reg_type {
EXTRA_REG_RSP_1 = 1, /* offcore_response_1 */
EXTRA_REG_LBR = 2, /* lbr_select */
EXTRA_REG_LDLAT = 3, /* ld_lat_threshold */
+ EXTRA_REG_FE = 4, /* fe_* */

EXTRA_REG_MAX /* number of entries needed */
};
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index 1d84b41..ef74c9d 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -205,6 +205,7 @@ static struct extra_reg intel_skl_extra_regs[] __read_mostly = {
INTEL_UEVENT_EXTRA_REG(0x01b7, MSR_OFFCORE_RSP_0, 0x3fffff8fffull, RSP_0),
INTEL_UEVENT_EXTRA_REG(0x01bb, MSR_OFFCORE_RSP_1, 0x3fffff8fffull, RSP_1),
INTEL_UEVENT_PEBS_LDLAT_EXTRA_REG(0x01cd),
+ INTEL_UEVENT_EXTRA_REG(0x01c6, MSR_PEBS_FRONTEND, 0x3fff17, FE),
EVENT_EXTRA_END
};

@@ -2891,6 +2892,8 @@ PMU_FORMAT_ATTR(offcore_rsp, "config1:0-63");

PMU_FORMAT_ATTR(ldlat, "config1:0-15");

+PMU_FORMAT_ATTR(frontend, "config1:0-23");
+
static struct attribute *intel_arch3_formats_attr[] = {
&format_attr_event.attr,
&format_attr_umask.attr,
@@ -2907,6 +2910,11 @@ static struct attribute *intel_arch3_formats_attr[] = {
NULL,
};

+static struct attribute *skl_format_attr[] = {
+ &format_attr_frontend.attr,
+ NULL,
+};
+
static __initconst const struct x86_pmu core_pmu = {
.name = "core",
.handle_irq = x86_pmu_handle_irq,
@@ -3516,7 +3524,8 @@ __init int intel_pmu_init(void)

x86_pmu.hw_config = hsw_hw_config;
x86_pmu.get_event_constraints = hsw_get_event_constraints;
- x86_pmu.cpu_events = hsw_events_attrs;
+ x86_pmu.format_attrs = merge_attr(intel_arch3_formats_attr,
+ skl_format_attr);
WARN_ON(!x86_pmu.format_attrs);
x86_pmu.cpu_events = hsw_events_attrs;
pr_cont("Skylake events, ");
--
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