[PATCH 6/7] powerpc/perf: Export Power8 memory hierarchy info to user space.
On Power8, the LDST field in SIER identifies the memory hierarchy level
(eg: L1, L2 etc), from which a data-cache miss for a marked instruction
was satisfied.
Use the 'perf_mem_data_src' object to export this hierarchy level to user
space. Fortunately, the memory hierarchy levels in Power8 map fairly easily
into the arch-neutral levels as described by the ldst_src_map[] table.
This hierarchy level information can be used with 'perf record --data'
or 'perf mem' command to analyze application behavior.
Usage:
$ perf mem record <application>
$ perf mem report
OR
$ perf record --data <application>
$ perf report -D
Sample records contain a 'data_src' field which encodes the memory
hierarchy level: Eg: data_src 0x442 indicates MEM_OP_LOAD, MEM_LVL_HIT,
MEM_LVL_L2 (i.e load hit L2).
Cc: Stephane Eranian <eran...@google.com>
Cc: Paul Mckerras <pau...@samba.org>
Cc: Michael Ellerman <mich...@ellerman.id.au>
Signed-off-by: Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/perf_event_server.h | 2 +
arch/powerpc/perf/core-book3s.c | 11 +++++
arch/powerpc/perf/power8-pmu.c | 53 ++++++++++++++++++++++++++
3 files changed, 66 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/include/asm/perf_event_server.h
b/arch/powerpc/include/asm/perf_event_server.h
index cc5f45b..2252798 100644
--- a/arch/powerpc/include/asm/perf_event_server.h
+++ b/arch/powerpc/include/asm/perf_event_server.h
@@ -37,6 +37,8 @@ struct power_pmu {
void (*config_bhrb)(u64 pmu_bhrb_filter);
void (*disable_pmc)(unsigned int pmc, unsigned long mmcr[]);
int (*limited_pmc_event)(u64 event_id);
+ void (*get_mem_data_src)(union perf_mem_data_src *dsrc,
+ struct pt_regs *regs);
u32 flags;
const struct attribute_group **attr_groups;
int n_generic;
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index a3985ae..e61fd05 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -1693,6 +1693,13 @@ ssize_t power_events_sysfs_show(struct device *dev,
return sprintf(page, "event=0x%02llx\n", pmu_attr->id);
}
+static inline void power_get_mem_data_src(union perf_mem_data_src *dsrc,
+ struct pt_regs *regs)
+{
+ if (ppmu->get_mem_data_src)
+ ppmu->get_mem_data_src(dsrc, regs);
+}
+
struct pmu power_pmu = {
.pmu_enable = power_pmu_enable,
.pmu_disable = power_pmu_disable,
@@ -1774,6 +1781,10 @@ static void record_and_restart(struct perf_event *event,
unsigned long val,
data.br_stack = &cpuhw->bhrb_stack;
}
+ if (event->attr.sample_type & PERF_SAMPLE_DATA_SRC &&
+ ppmu->get_mem_data_src)
+ ppmu->get_mem_data_src(&data.data_src, regs);
+
if (perf_event_overflow(event, &data, regs))
power_pmu_stop(event, 0);
}
diff --git a/arch/powerpc/perf/power8-pmu.c b/arch/powerpc/perf/power8-pmu.c
index 0a7b632..2aaae63 100644
--- a/arch/powerpc/perf/power8-pmu.c
+++ b/arch/powerpc/perf/power8-pmu.c
@@ -538,6 +538,58 @@ static struct attribute_group power8_pmu_events_group = {
.attrs = power8_events_attr,
};
+#define POWER8_SIER_TYPE_SHIFT 15
+#define POWER8_SIER_TYPE_MASK (0x7LL << POWER8_SIER_TYPE_SHIFT)
+
+#define POWER8_SIER_LDST_SHIFT 1
+#define POWER8_SIER_LDST_MASK (0x7LL << POWER8_SIER_LDST_SHIFT)
+
+#define P(a, b) PERF_MEM_S(a, b)
+#define PLH(a, b) (P(OP, LOAD) | P(LVL, HIT) | P(a, b))
+#define PSM(a, b) (P(OP, STORE) | P(LVL, MISS) | P(a, b))
+
+/*
+ * Power8 interpretations:
+ * REM_CCE1: 1-hop indicates L2/L3 cache of a different core on same chip
+ * REM_CCE2: 2-hop indicates different chip or different node.
+ */
+static u64 ldst_src_map[] = {
+ /* 000 */ P(LVL, NA),
+
+ /* 001 */ PLH(LVL, L1),
+ /* 010 */ PLH(LVL, L2),
+ /* 011 */ PLH(LVL, L3),
+ /* 100 */ PLH(LVL, LOC_RAM),
+ /* 101 */ PLH(LVL, REM_CCE1),
+ /* 110 */ PLH(LVL, REM_CCE2),
+
+ /* 111 */ PSM(LVL, L1),
+};
+
+static inline bool is_load_store_inst(u64 sier)
+{
+ u64 val;
+ val = (sier & POWER8_SIER_TYPE_MASK) >> POWER8_SIER_TYPE_SHIFT;
+
+ /* 1 = load, 2 = store */
+ return val == 1 || val == 2;
+}
+
+static void power8_get_mem_data_src(union perf_mem_data_src *dsrc,
+ struct pt_regs *regs)
+{
+ u64 idx;
+ u64 sier;
+
+ sier = mfspr(SPRN_SIER);
+
+ if (is_load_store_inst(sier)) {
+ idx = (sier & POWER8_SIER_LDST_MASK) >> POWER8_SIER_LDST_SHIFT;
+
+ dsrc->val |= ldst_src_map[idx];
+ }
+}
+
PMU_FORMAT_ATTR(event, "config:0-49");
PMU_FORMAT_ATTR(pmcxsel, "config:0-7");
PMU_FORMAT_ATTR(mark, "config:8");
@@ -641,6 +693,7 @@ static struct power_pmu power8_pmu = {
.get_constraint = power8_get_constraint,
.get_alternatives = power8_get_alternatives,
.disable_pmc = power8_disable_pmc,
+ .get_mem_data_src = power8_get_mem_data_src,
.flags = PPMU_HAS_SSLOT | PPMU_HAS_SIER | PPMU_BHRB |
PPMU_EBB,
.n_generic = ARRAY_SIZE(power8_generic_events),
.generic_events = power8_generic_events,
--
1.7.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
