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perf/Power7: Save dcache_src fields in sample record.

PATCH In review Sukadev Bhattiprolu 5 participants 9 messages Jun 7, 2013 – Jun 19, 2013

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Sukadev Bhattiprolu

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#0 lore raw

PATCH 1/2 perf/Power7: Save dcache_src fields in sample record.

From: Sukadev Bhattiprolu <[email protected]>
Date: Wed, 8 May 2013 22:59:29 -0700
Subject: [PATCH 1/2] perf/Power7: Save dcache_src fields in sample record.

Power7 saves the "perf-event vector" information in the mmcra register. Included in this event vector is a "data-cache source" field which identifies where in the memory-hierarchy the data for an instruction was found.

Use the 'struct perf_mem_data_source' to export the "data-cache source" field to user space.

The mapping between the Power7 hierarchy levels and the arch-neutral levels is, unfortunately, not trivial.

	Arch-neutral levels     Power7 levels
	---------------------------------------------------------
	local 	LVL_L2		local (same core) L2 (FROM_L2)
	local 	LVL_L3		local (same core) L3 (FROM_L3)

	1-hop	REM_CCE1	different core on same chip (FROM_L2.1, _L3.1)
	2-hops	REM_CCE2	remote (different chip, same node) (FROM_RL2L3)
	3-hops	REM_CCE3*	distant (different node)  (FROM_DL2L3)

	1-hop   REM_MEM1	unused
	2-hops 	REM_MEM2	remote (different chip, same node) (FROM_RMEM)
	3-hops 	REM_MEM3*	distant (different node) (FROM_DMEM)

* proposed "extended" levels.

AFAICT, Power7 supports one extra level in the cache-hierarchy, so we propose to add a new cache level, REM_CCE3 shown above.

To maintain consistency in terminology (i.e 2-hops = remote, 3-hops = distant), I propose leaving the REM_MEM1 unused and adding another level, REM_MEM3.

Further, in the above REM_CCE1 case, Power7 can also identify if the data came from the L2 or L3 cache of another core on the same chip. To describe this to user space, we propose to set ->mem_lvl to:

	PERF_MEM_LVL_REM_CCE1|PERF_MEM_LVL_L2

	PERF_MEM_LVL_REM_CCE1|PERF_MEM_LVL_L3

Either that or we could leave REM_CCE1 unused in Power and add two more levels:

	PERF_MEM_XLVL_REM_L2_CCE1
	PERF_MEM_XLVL_REM_L3_CCE1

The former approach seems less confusing and this patch uses that approach.

Signed-off-by Sukadev Bhattiprolu <[email protected]>
---
 arch/powerpc/include/asm/perf_event_server.h |    2 +
 arch/powerpc/perf/core-book3s.c              |    4 +
 arch/powerpc/perf/power7-pmu.c               |   81 ++++++++++++++++++++++++++
 include/uapi/linux/perf_event.h              |   12 +++-
 4 files changed, 97 insertions(+), 2 deletions(-)
arch/powerpc/include/asm/perf_event_server.h +2 -0
index f265049..f2d162b 100644
@@ -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)(struct perf_sample_data *data,
+				struct pt_regs *regs);
 	u32		flags;
 	const struct attribute_group	**attr_groups;
 	int		n_generic;
arch/powerpc/perf/core-book3s.c +4 -0
index 426180b..7778fa9 100644
@@ -1632,6 +1632,10 @@ 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, regs);
+
 		if (perf_event_overflow(event, &data, regs))
 			power_pmu_stop(event, 0);
 	}
arch/powerpc/perf/power7-pmu.c +81 -0

99 lines not on this page · raw message

include/uapi/linux/perf_event.h +10 -2
index fb104e5..f8d3269 100644
@@ -627,7 +627,8 @@ union perf_mem_data_src {
 			mem_snoop:5,	/* snoop mode */
 			mem_lock:2,	/* lock instr */
 			mem_dtlb:7,	/* tlb access */
-			mem_rsvd:31;
+			mem_xlvl:2,     /* extended memory levels */
+			mem_rsvd:29;
 	};
 };
 

@@ -654,7 +655,7 @@ union perf_mem_data_src {
 #define PERF_MEM_LVL_REM_CCE2	0x800 /* Remote Cache (2 hops) */
 #define PERF_MEM_LVL_IO		0x1000 /* I/O memory */
 #define PERF_MEM_LVL_UNC	0x2000 /* Uncached memory */
-#define PERF_MEM_LVL_SHIFT	5
+#define PERF_MEM_LVL_SHIFT	5      /* see also extended levels below */
 
 /* snoop mode */
 #define PERF_MEM_SNOOP_NA	0x01 /* not available */

@@ -679,6 +680,13 @@ union perf_mem_data_src {
 #define PERF_MEM_TLB_OS		0x40 /* OS fault handler */
 #define PERF_MEM_TLB_SHIFT	26
 
+#define PERF_MEM_XLVL_REM_RAM3	0x01 /* Remote memory (3 hops) */
+#define PERF_MEM_XLVL_REM_CCE3	0x02 /* Remote cache (3 hops) */
+#define PERF_MEM_XLVL_SHIFT	33
+
+/* Miscellaneous flags */
+#define PERF_MEM_MISC_CCE_MOD	0x4000 /* cache-hit, but entry was modified */
+
 #define PERF_MEM_S(a, s) \
 	(((u64)PERF_MEM_##a##_##s) << PERF_MEM_##a##_SHIFT)
Signature · 1 line
1.7.1
author
#1 lore raw

PATCH 2/2 perf: Add support for the mem_xlvl field.

Quoted 1 line

From 9f1a8a16e0ef36447e343d1cd4797c2b6a81225f Mon Sep 17 00:00:00 2001

From: Sukadev Bhattiprolu <[email protected]>
Date: Fri, 7 Jun 2013 13:26:31 -0700
Subject: [PATCH 2/2] perf: Add support for the mem_xlvl field.

A follow-on patch to adding perf_mem_data_src support for Power7. At this point, this is only touch-tested as am looking for feedback on the main kernel patch.

Signed-off-by Sukadev Bhattiprolu <[email protected]>
---
 tools/perf/util/sort.c |   31 ++++++++++++++++++++++++++++++-
 1 files changed, 30 insertions(+), 1 deletions(-)
tools/perf/util/sort.c +30 -1
index 5f52d49..24bbf4d 100644
@@ -631,9 +631,11 @@ static int hist_entry__tlb_snprintf(struct hist_entry *self, char *bf,
 static int64_t
 sort__lvl_cmp(struct hist_entry *left, struct hist_entry *right)
 {
+	int64_t rc;
 	union perf_mem_data_src data_src_l;
 	union perf_mem_data_src data_src_r;
 
+	data_src_l.val = data_src_r.val = (int64_t)0;
 	if (left->mem_info)
 		data_src_l = left->mem_info->data_src;
 	else

@@ -644,7 +646,11 @@ sort__lvl_cmp(struct hist_entry *left, struct hist_entry *right)
 	else
 		data_src_r.mem_lvl = PERF_MEM_LVL_NA;
 
-	return (int64_t)(data_src_r.mem_lvl - data_src_l.mem_lvl);
+	rc = data_src_r.mem_lvl - data_src_l.mem_lvl;
+	if (!rc)
+		rc = data_src_r.mem_xlvl - data_src_l.mem_xlvl;
+		
+	return rc;
 }
 
 static const char * const mem_lvl[] = {

@@ -663,7 +669,14 @@ static const char * const mem_lvl[] = {
 	"I/O",
 	"Uncached",
 };
+
+static const char * const mem_xlvl[] = {
+	"Remote RAM (3 hops)",
+	"Remote Cache (3 hops)",
+};
+
 #define NUM_MEM_LVL (sizeof(mem_lvl)/sizeof(const char *))
+#define NUM_MEM_XLVL (sizeof(mem_xlvl)/sizeof(const char *))
 
 static int hist_entry__lvl_snprintf(struct hist_entry *self, char *bf,
 				    size_t size, unsigned int width)

@@ -695,6 +708,22 @@ static int hist_entry__lvl_snprintf(struct hist_entry *self, char *bf,
 		strncat(out, mem_lvl[i], sz - l);
 		l += strlen(mem_lvl[i]);
 	}
+
+	m = 0;
+	if (self->mem_info)
+		m = self->mem_info->data_src.mem_xlvl;
+
+	for (i = 0; m && i < NUM_MEM_XLVL; i++, m >>= 1) {
+		if (!(m & 0x1))
+			continue;
+		if (l) {
+			strcat(out, " or ");
+			l += 4;
+		}
+		strncat(out, mem_xlvl[i], sz - l);
+		l += strlen(mem_xlvl[i]);
+	}
+
 	if (*out == '\0')
 		strcpy(out, "N/A");
 	if (hit)
Signature · 1 line
1.7.1
#3 lore raw
In reply to Sukadev Bhattiprolu
Quoted 7 lines

AFAICT, Power7 supports one extra level in the cache-hierarchy, so we propose to add a new cache level, REM_CCE3 shown above.

To maintain consistency in terminology (i.e 2-hops = remote, 3-hops = distant), I propose leaving the REM_MEM1 unused and adding another level, REM_MEM3.

Agreed.

Quoted 8 lines

Further, in the above REM_CCE1 case, Power7 can also identify if the data came from the L2 or L3 cache of another core on the same chip. To describe this to user space, we propose to set ->mem_lvl to:

	PERF_MEM_LVL_REM_CCE1|PERF_MEM_LVL_L2

	PERF_MEM_LVL_REM_CCE1|PERF_MEM_LVL_L3
Quoted 7 lines

Either that or we could leave REM_CCE1 unused in Power and add two more levels:

	PERF_MEM_XLVL_REM_L2_CCE1
	PERF_MEM_XLVL_REM_L3_CCE1

The former approach seems less confusing and this patch uses that approach.

Yeah, the former approach is simpler and makes sense.

Quoted 68 lines
Signed-off-by Sukadev Bhattiprolu <[email protected]>
---
 arch/powerpc/include/asm/perf_event_server.h |    2 +
 arch/powerpc/perf/core-book3s.c              |    4 +
 arch/powerpc/perf/power7-pmu.c               |   81 ++++++++++++++++++++++++++
 include/uapi/linux/perf_event.h              |   12 +++-
 4 files changed, 97 insertions(+), 2 deletions(-)
arch/powerpc/include/asm/perf_event_server.h +2 -0
index f265049..f2d162b 100644
@@ -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)(struct perf_sample_data *data,
+				struct pt_regs *regs);
 	u32		flags;
 	const struct attribute_group	**attr_groups;
 	int		n_generic;
arch/powerpc/perf/core-book3s.c +4 -0
index 426180b..7778fa9 100644
@@ -1632,6 +1632,10 @@ 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, regs);
+
 		if (perf_event_overflow(event, &data, regs))
 			power_pmu_stop(event, 0);
 	}
arch/powerpc/perf/power7-pmu.c +24 -0
index 3c475d6..af92bfe 100644
@@ -209,6 +209,85 @@ static int power7_get_alternatives(u64 event, unsigned int flags, u64 alt[])
 	return nalt;
 }
 
+#define	POWER7_MMCRA_PEMPTY		(0x1L << 63)
+#define	POWER7_MMCRA_FIN_STALL		(0x1L << 62)
+#define	POWER7_MMCRA_CMPL_STALL		(0x1L << 61)
+#define	POWER7_MMCRA_STALL_REASON_MASK	(0xFL << 60)
+
+#define	POWER7_MMCRA_DCACHE_MISS	(0x1L << 55)
+
+#define	POWER7_MMCRA_DCACHE_SRC_SHIFT	51
+#define	POWER7_MMCRA_DCACHE_SRC_MASK	(0xFL << POWER7_MMCRA_DCACHE_SRC_SHIFT)
+
+#define	POWER7_MMCRA_MDTLB_MISS		(0x1L << 50)
+
+#define	POWER7_MMCRA_MDTLB_SRC_SHIFT	46
+#define	POWER7_MMCRA_MDTLB_SRC_MASK	(0xFL << POWER7_MMCRA_MDTLB_SRC_SHIFT)
+
+#define	POWER7_MMCRA_MDERAT_MISS	(0x1L<< 45)
+#define	POWER7_MMCRA_MLSU_REJ		(0x1L<< 44)
+
+/* and so on */
+
+/*
+ * Map DCACHE_SRC fields to the Linux memory hierarchy levels.
+ *
+ * Bits 9..12 in the MMCRA indicate the source of a data-cache entry, with

arch/powerpc/perf/power7-pmu.c static int power7_get_alternatives(u64 event, unsigned int flags, u64 alt[]) · line 245

Quoted 10 lines
arch/powerpc/perf/power7-pmu.c +10 -0
+ * each of the 16 possible values referring to a specific source. Eg: if
+ * the 4-bits have the value 1 (0b0001), the dcache entry was found local
+ * L3 cache.
+ *
+ * We use the table, dcache_src_map, to map this value 1 to PERF_MEM_LVL_L3,
+ * the arch-neutral representation of the L3 cache.
+ *
+ * Similarly, in case of marked data TLB miss, bits 14..17 of the MMCRA
+ * indicate the load source of a marked DTLB  entry. dtlb_src_map[] gives
+ * the mapping to the arch-neutral values of the TLB source.

Where did you define dtlb_src_map[] ?

#5 lore raw
In reply to Sukadev Bhattiprolu
Quoted 37 lines · Sukadev Bhattiprolu

From: Sukadev Bhattiprolu <[email protected]>
Date: Wed, 8 May 2013 22:59:29 -0700
Subject: [PATCH 1/2] perf/Power7: Save dcache_src fields in sample record.

Power7 saves the "perf-event vector" information in the mmcra register. Included in this event vector is a "data-cache source" field which identifies where in the memory-hierarchy the data for an instruction was found.

Use the 'struct perf_mem_data_source' to export the "data-cache source" field to user space.

The mapping between the Power7 hierarchy levels and the arch-neutral levels is, unfortunately, not trivial.

Arch-neutral levels Power7 levels
---------------------------------------------------------
local LVL_L2 local (same core) L2 (FROM_L2)
local LVL_L3 local (same core) L3 (FROM_L3)

1-hop REM_CCE1 different core on same chip (FROM_L2.1, _L3.1)
2-hops REM_CCE2 remote (different chip, same node) (FROM_RL2L3)
3-hops REM_CCE3* distant (different node) (FROM_DL2L3)

1-hop REM_MEM1 unused
2-hops REM_MEM2 remote (different chip, same node) (FROM_RMEM)
3-hops REM_MEM3* distant (different node) (FROM_DMEM)

* proposed "extended" levels.

AFAICT, Power7 supports one extra level in the cache-hierarchy, so we propose to add a new cache level, REM_CCE3 shown above.

To maintain consistency in terminology (i.e 2-hops = remote, 3-hops = distant), I propose leaving the REM_MEM1 unused and adding another level, REM_MEM3.

Quoted 7 lines

Further, in the above REM_CCE1 case, Power7 can also identify if the data came from the L2 or L3 cache of another core on the same chip. To describe this to user space, we propose to set ->mem_lvl to:

        PERF_MEM_LVL_REM_CCE1|PERF_MEM_LVL_L2

        PERF_MEM_LVL_REM_CCE1|PERF_MEM_LVL_L3

Normally, that would be interpreted as:
- hit/miss on remote cache (1 hop) OR level 2 cache

But on PPC7, you're saying that this must be interpreted as:
- hit/miss on L2 cache of sibling core

How do you intend to document this interpretation?

Quoted 175 lines

Either that or we could leave REM_CCE1 unused in Power and add two more levels:

        PERF_MEM_XLVL_REM_L2_CCE1
        PERF_MEM_XLVL_REM_L3_CCE1

The former approach seems less confusing and this patch uses that approach.

Signed-off-by Sukadev Bhattiprolu <[email protected]>
---
 arch/powerpc/include/asm/perf_event_server.h |    2 +
 arch/powerpc/perf/core-book3s.c              |    4 +
 arch/powerpc/perf/power7-pmu.c               |   81 ++++++++++++++++++++++++++
 include/uapi/linux/perf_event.h              |   12 +++-
 4 files changed, 97 insertions(+), 2 deletions(-)
arch/powerpc/include/asm/perf_event_server.h +2 -0
index f265049..f2d162b 100644
@@ -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)(struct perf_sample_data *data,
+                               struct pt_regs *regs);
        u32             flags;
        const struct attribute_group    **attr_groups;
        int             n_generic;
arch/powerpc/perf/core-book3s.c +4 -0
index 426180b..7778fa9 100644
@@ -1632,6 +1632,10 @@ 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, regs);
+
                if (perf_event_overflow(event, &data, regs))
                        power_pmu_stop(event, 0);
        }
arch/powerpc/perf/power7-pmu.c +81 -0
index 3c475d6..af92bfe 100644
@@ -209,6 +209,85 @@ static int power7_get_alternatives(u64 event, unsigned int flags, u64 alt[])
        return nalt;
 }
 
+#define        POWER7_MMCRA_PEMPTY             (0x1L << 63)
+#define        POWER7_MMCRA_FIN_STALL          (0x1L << 62)
+#define        POWER7_MMCRA_CMPL_STALL         (0x1L << 61)
+#define        POWER7_MMCRA_STALL_REASON_MASK  (0xFL << 60)
+
+#define        POWER7_MMCRA_DCACHE_MISS        (0x1L << 55)
+
+#define        POWER7_MMCRA_DCACHE_SRC_SHIFT   51
+#define        POWER7_MMCRA_DCACHE_SRC_MASK    (0xFL << POWER7_MMCRA_DCACHE_SRC_SHIFT)
+
+#define        POWER7_MMCRA_MDTLB_MISS         (0x1L << 50)
+
+#define        POWER7_MMCRA_MDTLB_SRC_SHIFT    46
+#define        POWER7_MMCRA_MDTLB_SRC_MASK     (0xFL << POWER7_MMCRA_MDTLB_SRC_SHIFT)
+
+#define        POWER7_MMCRA_MDERAT_MISS        (0x1L<< 45)
+#define        POWER7_MMCRA_MLSU_REJ           (0x1L<< 44)
+
+/* and so on */
+
+/*
+ * Map DCACHE_SRC fields to the Linux memory hierarchy levels.
+ *
+ * Bits 9..12 in the MMCRA indicate the source of a data-cache entry, with
+ * each of the 16 possible values referring to a specific source. Eg: if
+ * the 4-bits have the value 1 (0b0001), the dcache entry was found local
+ * L3 cache.
+ *
+ * We use the table, dcache_src_map, to map this value 1 to PERF_MEM_LVL_L3,
+ * the arch-neutral representation of the L3 cache.
+ *
+ * Similarly, in case of marked data TLB miss, bits 14..17 of the MMCRA
+ * indicate the load source of a marked DTLB  entry. dtlb_src_map[] gives
+ * the mapping to the arch-neutral values of the TLB source.
+ *
+ * Architecture neutral to Power7 hierarchy levels:
+ *     1-hop  = different core on same chip (L2.1 or L3.1)
+ *     2-hops = remote (different chip on same node)
+ *     3-hops = distant (different node)
+ */
+static u64 dcache_src_map[] = {
+       PERF_MEM_S(LVL, L2),                     /* 00: FROM_L2 */
+       PERF_MEM_S(LVL, L3),                     /* 01: FROM_L3 */
+       PERF_MEM_S(LVL, NA),                     /* 02: Reserved */
+       PERF_MEM_S(LVL, NA),                     /* 03: Reserved */
+
+       PERF_MEM_LVL_L2|PERF_MEM_LVL_REM_CCE1,   /* 04: FROM_L2.1_SHR */
+       PERF_MEM_LVL_L2|PERF_MEM_LVL_REM_CCE1,   /* 05: FROM_L3.1_MOD */
+       PERF_MEM_LVL_L3|PERF_MEM_LVL_REM_CCE1,   /* 06: FROM_L2.1_SHR */
+       PERF_MEM_LVL_L3|PERF_MEM_LVL_REM_CCE1,   /* 07: FROM_L3.1_MOD */
+
+       PERF_MEM_S(LVL, REM_CCE2),               /* 08: FROM_RL2L3_SHR */
+       PERF_MEM_S(LVL, REM_CCE2),               /* 09: FROM_RL2L3_MOD */
+       PERF_MEM_S(XLVL, REM_CCE3),              /* 10: FROM_DL2L3_SHR */
+       PERF_MEM_S(XLVL, REM_CCE3),              /* 11: FROM_DL2L3_MOD */
+
+       PERF_MEM_S(LVL, LOC_RAM),                /* 12: FROM_LMEM */
+       PERF_MEM_S(LVL, REM_RAM2),               /* 13: FROM_RMEM */
+       PERF_MEM_S(XLVL, REM_RAM3),              /* 14: FROM_DMEM */
+
+       PERF_MEM_S(LVL, NA),                     /* 15: Reserved */
+};
+
+
+static void power7_get_mem_data_src(struct perf_sample_data *data,
+                               struct pt_regs *regs)
+{
+       unsigned long idx;
+       unsigned long mmcra = regs->dsisr;
+       union perf_mem_data_src *dsrc = &data->data_src;
+
+       if (mmcra & POWER7_MMCRA_DCACHE_MISS) {
+               idx = mmcra & POWER7_MMCRA_DCACHE_SRC_MASK;
+               idx >>= POWER7_MMCRA_DCACHE_SRC_SHIFT;
+
+               dsrc->val |= dcache_src_map[idx];
+       }
+}
+
 /*
  * Returns 1 if event counts things relating to marked instructions
  * and thus needs the MMCRA_SAMPLE_ENABLE bit set, or 0 if not.

@@ -438,6 +517,7 @@ static const struct attribute_group *power7_pmu_attr_groups[] = {
        NULL,
 };
 
+
 static struct power_pmu power7_pmu = {
        .name                   = "POWER7",
        .n_counter              = 6,

@@ -447,6 +527,7 @@ static struct power_pmu power7_pmu = {
        .compute_mmcr           = power7_compute_mmcr,
        .get_constraint         = power7_get_constraint,
        .get_alternatives       = power7_get_alternatives,
+       .get_mem_data_src       = power7_get_mem_data_src,
        .disable_pmc            = power7_disable_pmc,
        .flags                  = PPMU_ALT_SIPR,
        .attr_groups            = power7_pmu_attr_groups,
include/uapi/linux/perf_event.h +3 -2
index fb104e5..f8d3269 100644
@@ -627,7 +627,8 @@ union perf_mem_data_src {
                        mem_snoop:5,    /* snoop mode */
                        mem_lock:2,     /* lock instr */
                        mem_dtlb:7,     /* tlb access */
-                       mem_rsvd:31;
+                       mem_xlvl:2,     /* extended memory levels */
+                       mem_rsvd:29;
        };
 };
 

@@ -654,7 +655,7 @@ union perf_mem_data_src {
 #define PERF_MEM_LVL_REM_CCE2  0x800 /* Remote Cache (2 hops) */
 #define PERF_MEM_LVL_IO                0x1000 /* I/O memory */
 #define PERF_MEM_LVL_UNC       0x2000 /* Uncached memory */
-#define PERF_MEM_LVL_SHIFT     5
+#define PERF_MEM_LVL_SHIFT     5      /* see also extended levels below */
 
 /* snoop mode */
 #define PERF_MEM_SNOOP_NA      0x01 /* not available */

include/uapi/linux/perf_event.h union perf_mem_data_src { · line 686

Quoted 7 lines
include/uapi/linux/perf_event.h +4 -0
@@ -679,6 +680,13 @@ union perf_mem_data_src {
 #define PERF_MEM_TLB_OS                0x40 /* OS fault handler */
 #define PERF_MEM_TLB_SHIFT     26
 
+#define PERF_MEM_XLVL_REM_RAM3 0x01 /* Remote memory (3 hops) */
+#define PERF_MEM_XLVL_REM_CCE3 0x02 /* Remote cache (3 hops) */
+#define PERF_MEM_XLVL_SHIFT    33
+

You need to define a N/A bit there too.
Thats' necessary to indicate not available on non PPC architectures, such as x86.

include/uapi/linux/perf_event.h union perf_mem_data_src { · line 689

Quoted 4 lines
include/uapi/linux/perf_event.h +3 -0
+/* Miscellaneous flags */
+#define PERF_MEM_MISC_CCE_MOD  0x4000 /* cache-hit, but entry was modified */
+

Where is that flag used?
If internal, then it needs to be moved to the internal-only version of the header.

Quoted 6 lines
include/uapi/linux/perf_event.h +0 -1
 #define PERF_MEM_S(a, s) \
        (((u64)PERF_MEM_##a##_##s) << PERF_MEM_##a##_SHIFT)
 
--

1.7.1

author
#4 lore raw
In reply to Anshuman Khandual

Anshuman Khandual [[email protected]] wrote:

| > The former approach seems less confusing and this patch uses that approach.
| > 
| 
| Yeah, the former approach is simpler and makes sense.

Ok. Seems to make sense at least on Power.

<snip>

| > + * We use the table, dcache_src_map, to map this value 1 to PERF_MEM_LVL_L3,
| > + * the arch-neutral representation of the L3 cache.
| > + *
| > + * Similarly, in case of marked data TLB miss, bits 14..17 of the MMCRA
| > + * indicate the load source of a marked DTLB  entry. dtlb_src_map[] gives
| > + * the mapping to the arch-neutral values of the TLB source.
| 
| 
| Where did you define dtlb_src_map[] ?

Ah, the comment belongs in another patch that I am working on. That patch maps the PERF_MEM_TLB* flags to Power7.

Thanks for the comments.

Sukadev

author
#6 lore raw
In reply to Stephane Eranian

Stephane Eranian [[email protected]] wrote:

| > Further, in the above REM_CCE1 case, Power7 can also identify if the data came
| > from the L2 or L3 cache of another core on the same chip. To describe this to
| > user space, we propose to set ->mem_lvl to:
| >
| >         PERF_MEM_LVL_REM_CCE1|PERF_MEM_LVL_L2
| >
| >         PERF_MEM_LVL_REM_CCE1|PERF_MEM_LVL_L3
| 
| 
| Normally, that would be interpreted as:
|     - hit/miss on remote cache (1 hop) OR level 2 cache
| 
| But on PPC7, you're saying that this must be interpreted as:
|     - hit/miss on L2 cache of sibling core

Hmm, my proposed usage is an AND.

Did not realize it was strictly an OR of the levels. If so, we will have to define and use the extra levels I guess.

BTW, are there architectures that use the OR interpretation - IOW, are arbitrary combinations like local L1 or a remote 2-hop node's cache used ?

|
| How do you intend to document this interpretation?

Not sure yet as this is an early patch. 'perf report' man page would be one place.

Do/should architectures have the flexibility of interpretation ?

Personally, if we cannot interpret them as the AND of two levels, I think we would be better off defining the new levels below.

| 
| >
| >
| > Either that or we could leave REM_CCE1 unused in Power and add two more levels:
| >
| >         PERF_MEM_XLVL_REM_L2_CCE1
| >         PERF_MEM_XLVL_REM_L3_CCE1
| >
| > The former approach seems less confusing and this patch uses that approach.

<snip>

| > @@ -654,7 +655,7 @@ union perf_mem_data_src {
| >  #define PERF_MEM_LVL_REM_CCE2  0x800 /* Remote Cache (2 hops) */
| >  #define PERF_MEM_LVL_IO                0x1000 /* I/O memory */
| >  #define PERF_MEM_LVL_UNC       0x2000 /* Uncached memory */
| > -#define PERF_MEM_LVL_SHIFT     5
| > +#define PERF_MEM_LVL_SHIFT     5      /* see also extended levels below */
| >
| >  /* snoop mode */
| >  #define PERF_MEM_SNOOP_NA      0x01 /* not available */
| > @@ -679,6 +680,13 @@ union perf_mem_data_src {
| >  #define PERF_MEM_TLB_OS                0x40 /* OS fault handler */
| >  #define PERF_MEM_TLB_SHIFT     26
| >
| > +#define PERF_MEM_XLVL_REM_RAM3 0x01 /* Remote memory (3 hops) */
| > +#define PERF_MEM_XLVL_REM_CCE3 0x02 /* Remote cache (3 hops) */
| > +#define PERF_MEM_XLVL_SHIFT    33
| > +
| 
| You need to define a N/A bit there too.
| Thats' necessary to indicate not available on non PPC architectures,
| such as x86.

Ok.

| 
| >
| > +/* Miscellaneous flags */
| > +#define PERF_MEM_MISC_CCE_MOD  0x4000 /* cache-hit, but entry was modified */
| > +
| Where is that flag used?
| If internal, then it needs to be moved to the internal-only version of
| the header.

It is not internal, but the line snuck in when I was splitting a patch.

It refers to another feature in Power7 that I was trying to map into the perf_mem_data_src hierarchy. Power7 also indicates whether the entry we found in the cache was modified or shared.

Like with the HIT or MISS, it would/could be another state associated with each of the levels:

PERF_MEM_LVL_REM_CCE1
PERF_MEM_LVL_REM_CCE2
PERF_MEM_XLVL_REM_CCE3

I was toying with the idea of setting

	->mem_level = LVL_REM_CCE1|LVL_L2;
	->mem_misc = PERF_MEM_MISC_CCE_MOD;

to say that the cache entry we found in the sibling's L2 core was modified/dirty. (where ->mem_misc is carved out of the ->mem_rsvd bits).

Will come back to it after addressing the XLVL* part.

Thanks for the comments.

Sukadev

#2 lore raw

Re: [PATCH 2/2] perf: Add support for the mem_xlvl field.

In reply to Sukadev Bhattiprolu
Quoted 31 lines · Sukadev Bhattiprolu

From 9f1a8a16e0ef36447e343d1cd4797c2b6a81225f Mon Sep 17 00:00:00 2001
From: Sukadev Bhattiprolu <[email protected]>
Date: Fri, 7 Jun 2013 13:26:31 -0700
Subject: [PATCH 2/2] perf: Add support for the mem_xlvl field.

A follow-on patch to adding perf_mem_data_src support for Power7. At this point, this is only touch-tested as am looking for feedback on the main kernel patch.

Signed-off-by Sukadev Bhattiprolu <[email protected]>
---
 tools/perf/util/sort.c |   31 ++++++++++++++++++++++++++++++-
 1 files changed, 30 insertions(+), 1 deletions(-)
tools/perf/util/sort.c +2 -0
index 5f52d49..24bbf4d 100644
@@ -631,9 +631,11 @@ static int hist_entry__tlb_snprintf(struct hist_entry *self, char *bf,
 static int64_t
 sort__lvl_cmp(struct hist_entry *left, struct hist_entry *right)
 {
+	int64_t rc;
 	union perf_mem_data_src data_src_l;
 	union perf_mem_data_src data_src_r;
 
+	data_src_l.val = data_src_r.val = (int64_t)0;
 	if (left->mem_info)
 		data_src_l = left->mem_info->data_src;
 	else

tools/perf/util/sort.c sort__lvl_cmp(struct hist_entry *left, struct hist_entry *right) · line 652

Quoted 8 lines
tools/perf/util/sort.c +4 -1
@@ -644,7 +646,11 @@ sort__lvl_cmp(struct hist_entry *left, struct hist_entry *right)
 	else
 		data_src_r.mem_lvl = PERF_MEM_LVL_NA;
 
-	return (int64_t)(data_src_r.mem_lvl - data_src_l.mem_lvl);
+	rc = data_src_r.mem_lvl - data_src_l.mem_lvl;
+	if (!rc)
+		rc = data_src_r.mem_xlvl - data_src_l.mem_xlvl;
+

whitespace here

Quoted 50 lines
tools/perf/util/sort.c +24 -0
+	return rc;
 }
 
 static const char * const mem_lvl[] = {

@@ -663,7 +669,14 @@ static const char * const mem_lvl[] = {
 	"I/O",
 	"Uncached",
 };
+
+static const char * const mem_xlvl[] = {
+	"Remote RAM (3 hops)",
+	"Remote Cache (3 hops)",
+};
+
 #define NUM_MEM_LVL (sizeof(mem_lvl)/sizeof(const char *))
+#define NUM_MEM_XLVL (sizeof(mem_xlvl)/sizeof(const char *))
 
 static int hist_entry__lvl_snprintf(struct hist_entry *self, char *bf,
 				    size_t size, unsigned int width)

@@ -695,6 +708,22 @@ static int hist_entry__lvl_snprintf(struct hist_entry *self, char *bf,
 		strncat(out, mem_lvl[i], sz - l);
 		l += strlen(mem_lvl[i]);
 	}
+
+	m = 0;
+	if (self->mem_info)
+		m = self->mem_info->data_src.mem_xlvl;
+
+	for (i = 0; m && i < NUM_MEM_XLVL; i++, m >>= 1) {
+		if (!(m & 0x1))
+			continue;
+		if (l) {
+			strcat(out, " or ");
+			l += 4;
+		}
+		strncat(out, mem_xlvl[i], sz - l);
+		l += strlen(mem_xlvl[i]);
+	}
+
 	if (*out == '\0')
 		strcpy(out, "N/A");
 	if (hit)
Signature · 6 lines
1.7.1

_______________________________________________
Linuxppc-dev mailing list
[email protected]
https://lists.ozlabs.org/listinfo/linuxppc-dev
#7 lore raw
In reply to Sukadev Bhattiprolu

Suka,

One of these two patches breaks pmac32_defconfig and I suspect all other 32 bit configs (against mainline)

arch/powerpc/perf/core-book3s.c: In function 'record_and_restart':
arch/powerpc/perf/core-book3s.c:1632:4: error: passing argument 1 of 'ppmu->get_mem_data_src' from incompatible pointer type [-Werror] arch/powerpc/perf/core-book3s.c:1632:4: note: expected 'struct perf_sample_data *' but argument is of type 'struct perf_sample_data *'

benh is busy enough without this junk. Please check the simple things like white space and compile errors!

Mikey

Quoted 238 lines · Sukadev Bhattiprolu

From: Sukadev Bhattiprolu <[email protected]>
Date: Wed, 8 May 2013 22:59:29 -0700
Subject: [PATCH 1/2] perf/Power7: Save dcache_src fields in sample record.

Power7 saves the "perf-event vector" information in the mmcra register. Included in this event vector is a "data-cache source" field which identifies where in the memory-hierarchy the data for an instruction was found.

Use the 'struct perf_mem_data_source' to export the "data-cache source" field to user space.

The mapping between the Power7 hierarchy levels and the arch-neutral levels is, unfortunately, not trivial.

	Arch-neutral levels     Power7 levels
	---------------------------------------------------------
	local 	LVL_L2		local (same core) L2 (FROM_L2)
	local 	LVL_L3		local (same core) L3 (FROM_L3)

	1-hop	REM_CCE1	different core on same chip (FROM_L2.1, _L3.1)
	2-hops	REM_CCE2	remote (different chip, same node) (FROM_RL2L3)
	3-hops	REM_CCE3*	distant (different node)  (FROM_DL2L3)

	1-hop   REM_MEM1	unused
	2-hops 	REM_MEM2	remote (different chip, same node) (FROM_RMEM)
	3-hops 	REM_MEM3*	distant (different node) (FROM_DMEM)

* proposed "extended" levels.

AFAICT, Power7 supports one extra level in the cache-hierarchy, so we propose to add a new cache level, REM_CCE3 shown above.

To maintain consistency in terminology (i.e 2-hops = remote, 3-hops = distant), I propose leaving the REM_MEM1 unused and adding another level, REM_MEM3.

Further, in the above REM_CCE1 case, Power7 can also identify if the data came from the L2 or L3 cache of another core on the same chip. To describe this to user space, we propose to set ->mem_lvl to:

	PERF_MEM_LVL_REM_CCE1|PERF_MEM_LVL_L2

	PERF_MEM_LVL_REM_CCE1|PERF_MEM_LVL_L3

Either that or we could leave REM_CCE1 unused in Power and add two more levels:

	PERF_MEM_XLVL_REM_L2_CCE1
	PERF_MEM_XLVL_REM_L3_CCE1

The former approach seems less confusing and this patch uses that approach.

Signed-off-by Sukadev Bhattiprolu <[email protected]>
---
 arch/powerpc/include/asm/perf_event_server.h |    2 +
 arch/powerpc/perf/core-book3s.c              |    4 +
 arch/powerpc/perf/power7-pmu.c               |   81 ++++++++++++++++++++++++++
 include/uapi/linux/perf_event.h              |   12 +++-
 4 files changed, 97 insertions(+), 2 deletions(-)
arch/powerpc/include/asm/perf_event_server.h +2 -0
index f265049..f2d162b 100644
@@ -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)(struct perf_sample_data *data,
+				struct pt_regs *regs);
 	u32		flags;
 	const struct attribute_group	**attr_groups;
 	int		n_generic;
arch/powerpc/perf/core-book3s.c +4 -0
index 426180b..7778fa9 100644
@@ -1632,6 +1632,10 @@ 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, regs);
+
 		if (perf_event_overflow(event, &data, regs))
 			power_pmu_stop(event, 0);
 	}
arch/powerpc/perf/power7-pmu.c +81 -0
index 3c475d6..af92bfe 100644
@@ -209,6 +209,85 @@ static int power7_get_alternatives(u64 event, unsigned int flags, u64 alt[])
 	return nalt;
 }
 
+#define	POWER7_MMCRA_PEMPTY		(0x1L << 63)
+#define	POWER7_MMCRA_FIN_STALL		(0x1L << 62)
+#define	POWER7_MMCRA_CMPL_STALL		(0x1L << 61)
+#define	POWER7_MMCRA_STALL_REASON_MASK	(0xFL << 60)
+
+#define	POWER7_MMCRA_DCACHE_MISS	(0x1L << 55)
+
+#define	POWER7_MMCRA_DCACHE_SRC_SHIFT	51
+#define	POWER7_MMCRA_DCACHE_SRC_MASK	(0xFL << POWER7_MMCRA_DCACHE_SRC_SHIFT)
+
+#define	POWER7_MMCRA_MDTLB_MISS		(0x1L << 50)
+
+#define	POWER7_MMCRA_MDTLB_SRC_SHIFT	46
+#define	POWER7_MMCRA_MDTLB_SRC_MASK	(0xFL << POWER7_MMCRA_MDTLB_SRC_SHIFT)
+
+#define	POWER7_MMCRA_MDERAT_MISS	(0x1L<< 45)
+#define	POWER7_MMCRA_MLSU_REJ		(0x1L<< 44)
+
+/* and so on */
+
+/*
+ * Map DCACHE_SRC fields to the Linux memory hierarchy levels.
+ *
+ * Bits 9..12 in the MMCRA indicate the source of a data-cache entry, with
+ * each of the 16 possible values referring to a specific source. Eg: if
+ * the 4-bits have the value 1 (0b0001), the dcache entry was found local
+ * L3 cache.
+ *
+ * We use the table, dcache_src_map, to map this value 1 to PERF_MEM_LVL_L3,
+ * the arch-neutral representation of the L3 cache.
+ *
+ * Similarly, in case of marked data TLB miss, bits 14..17 of the MMCRA
+ * indicate the load source of a marked DTLB  entry. dtlb_src_map[] gives
+ * the mapping to the arch-neutral values of the TLB source.
+ *
+ * Architecture neutral to Power7 hierarchy levels:
+ * 	1-hop  = different core on same chip (L2.1 or L3.1)
+ * 	2-hops = remote (different chip on same node)
+ *	3-hops = distant (different node)
+ */
+static u64 dcache_src_map[] = {
+	PERF_MEM_S(LVL, L2),			 /* 00: FROM_L2 */
+	PERF_MEM_S(LVL, L3),			 /* 01: FROM_L3 */
+	PERF_MEM_S(LVL, NA),			 /* 02: Reserved */
+	PERF_MEM_S(LVL, NA),			 /* 03: Reserved */
+
+	PERF_MEM_LVL_L2|PERF_MEM_LVL_REM_CCE1,   /* 04: FROM_L2.1_SHR */
+	PERF_MEM_LVL_L2|PERF_MEM_LVL_REM_CCE1,   /* 05: FROM_L3.1_MOD */
+	PERF_MEM_LVL_L3|PERF_MEM_LVL_REM_CCE1,   /* 06: FROM_L2.1_SHR */
+	PERF_MEM_LVL_L3|PERF_MEM_LVL_REM_CCE1,   /* 07: FROM_L3.1_MOD */
+
+	PERF_MEM_S(LVL, REM_CCE2),		 /* 08: FROM_RL2L3_SHR */
+	PERF_MEM_S(LVL, REM_CCE2),		 /* 09: FROM_RL2L3_MOD */
+	PERF_MEM_S(XLVL, REM_CCE3),		 /* 10: FROM_DL2L3_SHR */
+	PERF_MEM_S(XLVL, REM_CCE3),		 /* 11: FROM_DL2L3_MOD */
+
+	PERF_MEM_S(LVL, LOC_RAM),		 /* 12: FROM_LMEM */
+	PERF_MEM_S(LVL, REM_RAM2),		 /* 13: FROM_RMEM */
+	PERF_MEM_S(XLVL, REM_RAM3),		 /* 14: FROM_DMEM */
+
+	PERF_MEM_S(LVL, NA),			 /* 15: Reserved */
+};
+
+
+static void power7_get_mem_data_src(struct perf_sample_data *data,
+				struct pt_regs *regs)
+{
+	unsigned long idx;
+	unsigned long mmcra = regs->dsisr;
+	union perf_mem_data_src *dsrc = &data->data_src;
+
+	if (mmcra & POWER7_MMCRA_DCACHE_MISS) {
+		idx = mmcra & POWER7_MMCRA_DCACHE_SRC_MASK;
+		idx >>= POWER7_MMCRA_DCACHE_SRC_SHIFT;
+
+		dsrc->val |= dcache_src_map[idx];
+	}
+}
+
 /*
  * Returns 1 if event counts things relating to marked instructions
  * and thus needs the MMCRA_SAMPLE_ENABLE bit set, or 0 if not.

@@ -438,6 +517,7 @@ static const struct attribute_group *power7_pmu_attr_groups[] = {
 	NULL,
 };
 
+
 static struct power_pmu power7_pmu = {
 	.name			= "POWER7",
 	.n_counter		= 6,

@@ -447,6 +527,7 @@ static struct power_pmu power7_pmu = {
 	.compute_mmcr		= power7_compute_mmcr,
 	.get_constraint		= power7_get_constraint,
 	.get_alternatives	= power7_get_alternatives,
+	.get_mem_data_src	= power7_get_mem_data_src,
 	.disable_pmc		= power7_disable_pmc,
 	.flags			= PPMU_ALT_SIPR,
 	.attr_groups		= power7_pmu_attr_groups,
include/uapi/linux/perf_event.h +10 -2
index fb104e5..f8d3269 100644
@@ -627,7 +627,8 @@ union perf_mem_data_src {
 			mem_snoop:5,	/* snoop mode */
 			mem_lock:2,	/* lock instr */
 			mem_dtlb:7,	/* tlb access */
-			mem_rsvd:31;
+			mem_xlvl:2,     /* extended memory levels */
+			mem_rsvd:29;
 	};
 };
 

@@ -654,7 +655,7 @@ union perf_mem_data_src {
 #define PERF_MEM_LVL_REM_CCE2	0x800 /* Remote Cache (2 hops) */
 #define PERF_MEM_LVL_IO		0x1000 /* I/O memory */
 #define PERF_MEM_LVL_UNC	0x2000 /* Uncached memory */
-#define PERF_MEM_LVL_SHIFT	5
+#define PERF_MEM_LVL_SHIFT	5      /* see also extended levels below */
 
 /* snoop mode */
 #define PERF_MEM_SNOOP_NA	0x01 /* not available */

@@ -679,6 +680,13 @@ union perf_mem_data_src {
 #define PERF_MEM_TLB_OS		0x40 /* OS fault handler */
 #define PERF_MEM_TLB_SHIFT	26
 
+#define PERF_MEM_XLVL_REM_RAM3	0x01 /* Remote memory (3 hops) */
+#define PERF_MEM_XLVL_REM_CCE3	0x02 /* Remote cache (3 hops) */
+#define PERF_MEM_XLVL_SHIFT	33
+
+/* Miscellaneous flags */
+#define PERF_MEM_MISC_CCE_MOD	0x4000 /* cache-hit, but entry was modified */
+
 #define PERF_MEM_S(a, s) \
 	(((u64)PERF_MEM_##a##_##s) << PERF_MEM_##a##_SHIFT)
Signature · 6 lines
1.7.1

_______________________________________________
Linuxppc-dev mailing list
[email protected]
https://lists.ozlabs.org/listinfo/linuxppc-dev
author
#8 lore raw

Michael Neuling [[email protected]] wrote:

| Suka,
| 
| One of these two patches breaks pmac32_defconfig and I suspect all other
| 32 bit configs (against mainline)
| 
| arch/powerpc/perf/core-book3s.c: In function 'record_and_restart':
| arch/powerpc/perf/core-book3s.c:1632:4: error: passing argument 1 of 'ppmu->get_mem_data_src' from incompatible pointer type [-Werror]
| arch/powerpc/perf/core-book3s.c:1632:4: note: expected 'struct perf_sample_data *' but argument is of type 'struct perf_sample_data *'
| 
| benh is busy enough without this junk.  Please check the simple things
| like white space and compile errors!

Sorry about that.

BTW, this was an early patch more to get some feedback on mapping of memory hierarchy levels to Power and not intended to be merged. I have been reworking the patch based on other comments.

Sukadev