From: Athira Rajeev
In power9 and before platforms, the default event used for cyles and
instructions is PM_CYC (0x0001e) and PM_INST_CMPL (0x2) respectively.
These events uses two programmable PMCs and by default will count
irrespective of the run latch state. But since it is using programmable
PMCs, these events will cause multiplexing with basic event set supported
by perf stat. Hence in power10, performance monitoring unit (PMU) driver
uses performance monitor counter 5 (PMC5) and performance monitor counter6
(PMC6) for counting instructions and cycles.
In power10, event used for cycles is PM_RUN_CYC (0x600F4) and instructions
is 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 not set, PMC5/6 will not count when
CTRL[RUN] is zero. This could lead to miss some counts if a thread
is in idle state during system wide profiling.
Patch sets the CC56RUN bit in MMCR0 for power10 which makes PMC5 and
PMC6 count instructions and cycles regardless of the run bit. Since
this change make PMC5/6 count as PM_INST_CMPL/PM_CYC, renamed 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
Reviewed-by: Madhavan Srinivasan
---
Changelog:
Updated commit message to explain in detail on why and
how it affects counting.
Notes on testing done for this change:
Tested this patch change with a kernel module that
turns off and turns on the runlatch. kernel module also
reads the counter values for PMC5 and PMC6 during the
period when runlatch is off.
- Started PMU counters via "perf stat" and loaded the
test module.
- Checked the counter values captured from module during
the runlatch off period.
- Verified that counters were frozen without the patch and
with the patch, observed counters were incrementing.
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 93be7197d250..564f14097f07 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,0x2);
+EVENT(PM_CYC_ALT, 0x0001e);
+EVENT(PM_INST_CMPL_ALT,0x2);
/*
* Memory Access Events
diff --git a/arch/powerpc/perf/power10-pmu.c b/arch/powerpc/perf/power10-pmu.c
index f9d64c63bb4a..9dd75f385837 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
