[tip:perf/core] perf/x86/intel/pt: Add new timing packet enables

From: tip-bot for Alexander Shishkin
Date: Tue Aug 04 2015 - 04:56:28 EST

Next message: tip-bot for Andi Kleen: "[tip:perf/core] perf/x86/intel: Add support for PEBSv3 profiling"
Previous message: tip-bot for Alexander Shishkin: "[tip:perf/core] perf/x86/intel/pt: Do not force sync packets on every schedule-in"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

Commit-ID: b1bf72d6691cc33fc7763fc8ec77df42ca1a8702
Gitweb: http://git.kernel.org/tip/b1bf72d6691cc33fc7763fc8ec77df42ca1a8702
Author: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
AuthorDate: Thu, 30 Jul 2015 16:15:31 +0300
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 4 Aug 2015 10:16:55 +0200

perf/x86/intel/pt: Add new timing packet enables

Intel PT chapter in the new Intel Architecture SDM adds several packets
corresponding enable bits and registers that control packet generation.
Also, additional bits in the Intel PT CPUID leaf were added to enumerate
presence and parameters of these new packets and features.

The packets and enables are:

* CYC: cycle accurate mode, provides the number of cycles elapsed since
previous CYC packet; its presence and available threshold values are
enumerated via CPUID;

* MTC: mini time counter packets, used for tracking TSC time between
full TSC packets; its presence and available resolution options are
enumerated via CPUID;

* PSB packet period is now configurable, available period values are
enumerated via CPUID.

This patch adds corresponding bit and register definitions, pmu driver
capabilities based on CPUID enumeration, new attribute format bits for
the new featurens and extends event configuration validation function
to take these into account.

Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: acme@xxxxxxxxxxxxx
Cc: adrian.hunter@xxxxxxxxx
Cc: hpa@xxxxxxxxx
Link: http://lkml.kernel.org/r/1438262131-12725-1-git-send-email-alexander.shishkin@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/include/asm/msr-index.h | 8 ++++
arch/x86/kernel/cpu/intel_pt.h | 6 +++
arch/x86/kernel/cpu/perf_event_intel_pt.c | 68 ++++++++++++++++++++++++++++++-
3 files changed, 81 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index 9ebc3d0..c665d34 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -80,13 +80,21 @@

#define MSR_IA32_RTIT_CTL 0x00000570
#define RTIT_CTL_TRACEEN BIT(0)
+#define RTIT_CTL_CYCLEACC BIT(1)
#define RTIT_CTL_OS BIT(2)
#define RTIT_CTL_USR BIT(3)
#define RTIT_CTL_CR3EN BIT(7)
#define RTIT_CTL_TOPA BIT(8)
+#define RTIT_CTL_MTC_EN BIT(9)
#define RTIT_CTL_TSC_EN BIT(10)
#define RTIT_CTL_DISRETC BIT(11)
#define RTIT_CTL_BRANCH_EN BIT(13)
+#define RTIT_CTL_MTC_RANGE_OFFSET 14
+#define RTIT_CTL_MTC_RANGE (0x0full << RTIT_CTL_MTC_RANGE_OFFSET)
+#define RTIT_CTL_CYC_THRESH_OFFSET 19
+#define RTIT_CTL_CYC_THRESH (0x0full << RTIT_CTL_CYC_THRESH_OFFSET)
+#define RTIT_CTL_PSB_FREQ_OFFSET 24
+#define RTIT_CTL_PSB_FREQ (0x0full << RTIT_CTL_PSB_FREQ_OFFSET)
#define MSR_IA32_RTIT_STATUS 0x00000571
#define RTIT_STATUS_CONTEXTEN BIT(1)
#define RTIT_STATUS_TRIGGEREN BIT(2)
diff --git a/arch/x86/kernel/cpu/intel_pt.h b/arch/x86/kernel/cpu/intel_pt.h
index 1c338b0..feb293e 100644
--- a/arch/x86/kernel/cpu/intel_pt.h
+++ b/arch/x86/kernel/cpu/intel_pt.h
@@ -72,9 +72,15 @@ struct topa_entry {
enum pt_capabilities {
PT_CAP_max_subleaf = 0,
PT_CAP_cr3_filtering,
+ PT_CAP_psb_cyc,
+ PT_CAP_mtc,
PT_CAP_topa_output,
PT_CAP_topa_multiple_entries,
+ PT_CAP_single_range_output,
PT_CAP_payloads_lip,
+ PT_CAP_mtc_periods,
+ PT_CAP_cycle_thresholds,
+ PT_CAP_psb_periods,
};

struct pt_pmu {
diff --git a/arch/x86/kernel/cpu/perf_event_intel_pt.c b/arch/x86/kernel/cpu/perf_event_intel_pt.c
index cc58ef8..e20cfac 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_pt.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_pt.c
@@ -65,9 +65,15 @@ static struct pt_cap_desc {
} pt_caps[] = {
PT_CAP(max_subleaf, 0, CR_EAX, 0xffffffff),
PT_CAP(cr3_filtering, 0, CR_EBX, BIT(0)),
+ PT_CAP(psb_cyc, 0, CR_EBX, BIT(1)),
+ PT_CAP(mtc, 0, CR_EBX, BIT(3)),
PT_CAP(topa_output, 0, CR_ECX, BIT(0)),
PT_CAP(topa_multiple_entries, 0, CR_ECX, BIT(1)),
+ PT_CAP(single_range_output, 0, CR_ECX, BIT(2)),
PT_CAP(payloads_lip, 0, CR_ECX, BIT(31)),
+ PT_CAP(mtc_periods, 1, CR_EAX, 0xffff0000),
+ PT_CAP(cycle_thresholds, 1, CR_EBX, 0xffff),
+ PT_CAP(psb_periods, 1, CR_EBX, 0xffff0000),
};

static u32 pt_cap_get(enum pt_capabilities cap)
@@ -94,12 +100,22 @@ static struct attribute_group pt_cap_group = {
.name = "caps",
};

+PMU_FORMAT_ATTR(cyc, "config:1" );
+PMU_FORMAT_ATTR(mtc, "config:9" );
PMU_FORMAT_ATTR(tsc, "config:10" );
PMU_FORMAT_ATTR(noretcomp, "config:11" );
+PMU_FORMAT_ATTR(mtc_period, "config:14-17" );
+PMU_FORMAT_ATTR(cyc_thresh, "config:19-22" );
+PMU_FORMAT_ATTR(psb_period, "config:24-27" );

static struct attribute *pt_formats_attr[] = {
+ &format_attr_cyc.attr,
+ &format_attr_mtc.attr,
&format_attr_tsc.attr,
&format_attr_noretcomp.attr,
+ &format_attr_mtc_period.attr,
+ &format_attr_cyc_thresh.attr,
+ &format_attr_psb_period.attr,
NULL,
};

@@ -170,15 +186,65 @@ fail:
return ret;
}

-#define PT_CONFIG_MASK (RTIT_CTL_TSC_EN | RTIT_CTL_DISRETC)
+#define RTIT_CTL_CYC_PSB (RTIT_CTL_CYCLEACC | \
+ RTIT_CTL_CYC_THRESH | \
+ RTIT_CTL_PSB_FREQ)
+
+#define RTIT_CTL_MTC (RTIT_CTL_MTC_EN | \
+ RTIT_CTL_MTC_RANGE)
+
+#define PT_CONFIG_MASK (RTIT_CTL_TSC_EN | \
+ RTIT_CTL_DISRETC | \
+ RTIT_CTL_CYC_PSB | \
+ RTIT_CTL_MTC)

static bool pt_event_valid(struct perf_event *event)
{
u64 config = event->attr.config;
+ u64 allowed, requested;

if ((config & PT_CONFIG_MASK) != config)
return false;

+ if (config & RTIT_CTL_CYC_PSB) {
+ if (!pt_cap_get(PT_CAP_psb_cyc))
+ return false;
+
+ allowed = pt_cap_get(PT_CAP_psb_periods);
+ requested = (config & RTIT_CTL_PSB_FREQ) >>
+ RTIT_CTL_PSB_FREQ_OFFSET;
+ if (requested && (!(allowed & BIT(requested))))
+ return false;
+
+ allowed = pt_cap_get(PT_CAP_cycle_thresholds);
+ requested = (config & RTIT_CTL_CYC_THRESH) >>
+ RTIT_CTL_CYC_THRESH_OFFSET;
+ if (requested && (!(allowed & BIT(requested))))
+ return false;
+ }
+
+ if (config & RTIT_CTL_MTC) {
+ /*
+ * In the unlikely case that CPUID lists valid mtc periods,
+ * but not the mtc capability, drop out here.
+ *
+ * Spec says that setting mtc period bits while mtc bit in
+ * CPUID is 0 will #GP, so better safe than sorry.
+ */
+ if (!pt_cap_get(PT_CAP_mtc))
+ return false;
+
+ allowed = pt_cap_get(PT_CAP_mtc_periods);
+ if (!allowed)
+ return false;
+
+ requested = (config & RTIT_CTL_MTC_RANGE) >>
+ RTIT_CTL_MTC_RANGE_OFFSET;
+
+ if (!(allowed & BIT(requested)))
+ return false;
+ }
+
return true;
}

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

Next message: tip-bot for Andi Kleen: "[tip:perf/core] perf/x86/intel: Add support for PEBSv3 profiling"
Previous message: tip-bot for Alexander Shishkin: "[tip:perf/core] perf/x86/intel/pt: Do not force sync packets on every schedule-in"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]