[PATCH 5.14 609/849] powerpc/perf: Fix cycles/instructions as PM_CYC/PM_INST_CMPL in power10

Greg Kroah-Hartman
2021-11-15T23:13:44Z

From: Athira Rajeev <atrajeev@linux.vnet.ibm.cm>

[ Upstream commit 8f6aca0e0f26eaaee670cd27896993a45cdc8f9e ]

On power9 and earlier platforms, the default event used for cyles and
instructions is PM_CYC (0x0001e) and PM_INST_CMPL (0x00002)
respectively. These events use two programmable PMCs and by default will
count irrespective of the run latch state (idle state). But since they
use programmable PMCs, these events can lead to multiplexing with other
events, because there are only 4 programmable PMCs. Hence in power10,
performance monitoring unit (PMU) driver uses performance monitor
counter 5 (PMC5) and performance monitor counter6 (PMC6) for counting
instructions and cycles.

Currently on power10, the event used for cycles is PM_RUN_CYC (0x600F4)
and instructions uses PM_RUN_INST_CMPL (0x500fa). But counting of these
events in idle state is controlled by the CC56RUN bit setting in Monitor
Mode Control Register0 (MMCR0). If the CC56RUN bit is zero, PMC5/6 will
not count when CTRL[RUN] (run latch) is zero. This could lead to missing
some counts if a thread is in idle state during system wide profiling.

To fix it, set the CC56RUN bit in MMCR0 for power10, which makes PMC5
and PMC6 count instructions and cycles regardless of the run latch
state. Since this change make PMC5/6 count as PM_INST_CMPL/PM_CYC,
rename the event code 0x600f4 as PM_CYC instead of PM_RUN_CYC and event
code 0x500fa as PM_INST_CMPL instead of PM_RUN_INST_CMPL. The changes
are only for PMC5/6 event codes and will not affect the behaviour of
PM_RUN_CYC/PM_RUN_INST_CMPL if progammed in other PMC's.

Fixes: a64e697cef23 ("powerpc/perf: power10 Performance Monitoring support")
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.cm>
Reviewed-by: Madhavan Srinivasan <maddy@linux.ibm.com>
[mpe: Tweak change log wording for style and consistency]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211007075121.28497-1-atrajeev@linux.vnet.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/powerpc/perf/power10-events-list.h | 8 ++---
arch/powerpc/perf/power10-pmu.c | 44 +++++++++++++++++--------
2 files changed, 35 insertions(+), 17 deletions(-)

diff --git a/arch/powerpc/perf/power10-events-list.h b/arch/powerpc/perf/power10-events-list.h
index 93be7197d2502..564f14097f07b 100644
--- a/arch/powerpc/perf/power10-events-list.h
+++ b/arch/powerpc/perf/power10-events-list.h
@@ -9,10 +9,10 @@
/*
* Power10 event codes.
*/
-EVENT(PM_RUN_CYC, 0x600f4);
+EVENT(PM_CYC, 0x600f4);
EVENT(PM_DISP_STALL_CYC, 0x100f8);
EVENT(PM_EXEC_STALL, 0x30008);
-EVENT(PM_RUN_INST_CMPL, 0x500fa);
+EVENT(PM_INST_CMPL, 0x500fa);
EVENT(PM_BR_CMPL, 0x4d05e);
EVENT(PM_BR_MPRED_CMPL, 0x400f6);
EVENT(PM_BR_FIN, 0x2f04a);
@@ -50,8 +50,8 @@ EVENT(PM_DTLB_MISS, 0x300fc);
/* ITLB Reloaded */
EVENT(PM_ITLB_MISS, 0x400fc);

-EVENT(PM_RUN_CYC_ALT, 0x0001e);
-EVENT(PM_RUN_INST_CMPL_ALT, 0x00002);
+EVENT(PM_CYC_ALT, 0x0001e);
+EVENT(PM_INST_CMPL_ALT, 0x00002);

/*
* Memory Access Events
diff --git a/arch/powerpc/perf/power10-pmu.c b/arch/powerpc/perf/power10-pmu.c
index f9d64c63bb4a7..9dd75f3858372 100644
--- a/arch/powerpc/perf/power10-pmu.c
+++ b/arch/powerpc/perf/power10-pmu.c
@@ -91,8 +91,8 @@ extern u64 PERF_REG_EXTENDED_MASK;

/* Table of alternatives, sorted by column 0 */
static const unsigned int power10_event_alternatives[][MAX_ALT] = {
- { PM_RUN_CYC_ALT, PM_RUN_CYC },
- { PM_RUN_INST_CMPL_ALT, PM_RUN_INST_CMPL },
+ { PM_CYC_ALT, PM_CYC },
+ { PM_INST_CMPL_ALT, PM_INST_CMPL },
};

static int power10_get_alternatives(u64 event, unsigned int flags, u64 alt[])
@@ -118,8 +118,8 @@ static int power10_check_attr_config(struct perf_event *ev)
return 0;
}

-GENERIC_EVENT_ATTR(cpu-cycles, PM_RUN_CYC);
-GENERIC_EVENT_ATTR(instructions, PM_RUN_INST_CMPL);
+GENERIC_EVENT_ATTR(cpu-cycles, PM_CYC);
+GENERIC_EVENT_ATTR(instructions, PM_INST_CMPL);
GENERIC_EVENT_ATTR(branch-instructions, PM_BR_CMPL);
GENERIC_EVENT_ATTR(branch-misses, PM_BR_MPRED_CMPL);
GENERIC_EVENT_ATTR(cache-references, PM_LD_REF_L1);
@@ -148,8 +148,8 @@ CACHE_EVENT_ATTR(dTLB-load-misses, PM_DTLB_MISS);
CACHE_EVENT_ATTR(iTLB-load-misses, PM_ITLB_MISS);

static struct attribute *power10_events_attr_dd1[] = {
- GENERIC_EVENT_PTR(PM_RUN_CYC),
- GENERIC_EVENT_PTR(PM_RUN_INST_CMPL),
+ GENERIC_EVENT_PTR(PM_CYC),
+ GENERIC_EVENT_PTR(PM_INST_CMPL),
GENERIC_EVENT_PTR(PM_BR_CMPL),
GENERIC_EVENT_PTR(PM_BR_MPRED_CMPL),
GENERIC_EVENT_PTR(PM_LD_REF_L1),
@@ -173,8 +173,8 @@ static struct attribute *power10_events_attr_dd1[] = {
};

static struct attribute *power10_events_attr[] = {
- GENERIC_EVENT_PTR(PM_RUN_CYC),
- GENERIC_EVENT_PTR(PM_RUN_INST_CMPL),
+ GENERIC_EVENT_PTR(PM_CYC),
+ GENERIC_EVENT_PTR(PM_INST_CMPL),
GENERIC_EVENT_PTR(PM_BR_FIN),
GENERIC_EVENT_PTR(PM_MPRED_BR_FIN),
GENERIC_EVENT_PTR(PM_LD_REF_L1),
@@ -271,8 +271,8 @@ static const struct attribute_group *power10_pmu_attr_groups[] = {
};

static int power10_generic_events_dd1[] = {
- [PERF_COUNT_HW_CPU_CYCLES] = PM_RUN_CYC,
- [PERF_COUNT_HW_INSTRUCTIONS] = PM_RUN_INST_CMPL,
+ [PERF_COUNT_HW_CPU_CYCLES] = PM_CYC,
+ [PERF_COUNT_HW_INSTRUCTIONS] = PM_INST_CMPL,
[PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = PM_BR_CMPL,
[PERF_COUNT_HW_BRANCH_MISSES] = PM_BR_MPRED_CMPL,
[PERF_COUNT_HW_CACHE_REFERENCES] = PM_LD_REF_L1,
@@ -280,8 +280,8 @@ static int power10_generic_events_dd1[] = {
};

static int power10_generic_events[] = {
- [PERF_COUNT_HW_CPU_CYCLES] = PM_RUN_CYC,
- [PERF_COUNT_HW_INSTRUCTIONS] = PM_RUN_INST_CMPL,
+ [PERF_COUNT_HW_CPU_CYCLES] = PM_CYC,
+ [PERF_COUNT_HW_INSTRUCTIONS] = PM_INST_CMPL,
[PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = PM_BR_FIN,
[PERF_COUNT_HW_BRANCH_MISSES] = PM_MPRED_BR_FIN,
[PERF_COUNT_HW_CACHE_REFERENCES] = PM_LD_REF_L1,
@@ -548,6 +548,24 @@ static u64 power10_cache_events[C(MAX)][C(OP_MAX)][C(RESULT_MAX)] = {

#undef C

+/*
+ * Set the MMCR0[CC56RUN] bit to enable counting for
+ * PMC5 and PMC6 regardless of the state of CTRL[RUN],
+ * so that we can use counters 5 and 6 as PM_INST_CMPL and
+ * PM_CYC.
+ */
+static int power10_compute_mmcr(u64 event[], int n_ev,
+ unsigned int hwc[], struct mmcr_regs *mmcr,
+ struct perf_event *pevents[], u32 flags)
+{
+ int ret;
+
+ ret = isa207_compute_mmcr(event, n_ev, hwc, mmcr, pevents, flags);
+ if (!ret)
+ mmcr->mmcr0 |= MMCR0_C56RUN;
+ return ret;
+}
+
static struct power_pmu power10_pmu = {
.name = "POWER10",
.n_counter = MAX_PMU_COUNTERS,
@@ -555,7 +573,7 @@ static struct power_pmu power10_pmu = {
.test_adder = ISA207_TEST_ADDER,
.group_constraint_mask = CNST_CACHE_PMC4_MASK,
.group_constraint_val = CNST_CACHE_PMC4_VAL,
- .compute_mmcr = isa207_compute_mmcr,
+ .compute_mmcr = power10_compute_mmcr,
.config_bhrb = power10_config_bhrb,
.bhrb_filter_map = power10_bhrb_filter_map,
.get_constraint = isa207_get_constraint,
--
2.33.0