Add PERF_SAMPLE_CLOCK to sample some other clock.
The patch allows for 16 possible clock selections
with the only initial possibility an architecture-specific
clock which will be used for TSC on x86.
Although there are only 16 possible clock selections,
it is envisioned that POSIX clock ids would be a
single selection, with the actual clock id provided
in another perf_event_attr member.
Based-on-patch-by: Pawel Moll <pawel.m...@arm.com>
Signed-off-by: Adrian Hunter <adrian.hun...@intel.com>
---
include/linux/perf_event.h | 3 ++-
include/uapi/linux/perf_event.h | 19 +++++++++++++++++--
kernel/events/core.c | 30 ++++++++++++++++++++++++++++++
kernel/events/internal.h | 4 ++++
4 files changed, 53 insertions(+), 3 deletions(-)
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index efe2d2d..e86637e 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -655,7 +655,7 @@ extern void perf_pmu_migrate_context(struct pmu *pmu,
int src_cpu, int dst_cpu);
extern u64 perf_event_read_value(struct perf_event *event,
u64 *enabled, u64 *running);
-
+u64 perf_sample_clock_arch(void);
struct perf_sample_data {
/*
@@ -687,6 +687,7 @@ struct perf_sample_data {
u32 cpu;
u32 reserved;
} cpu_entry;
+ u64 clock;
struct perf_callchain_entry *callchain;
/*
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index be9ff06..4d081d5 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -139,8 +139,9 @@ enum perf_event_sample_format {
PERF_SAMPLE_IDENTIFIER = 1U << 16,
PERF_SAMPLE_TRANSACTION = 1U << 17,
PERF_SAMPLE_REGS_INTR = 1U << 18,
+ PERF_SAMPLE_CLOCK = 1U << 19,
- PERF_SAMPLE_MAX = 1U << 19, /* non-ABI */
+ PERF_SAMPLE_MAX = 1U << 20, /* non-ABI */
};
/*
@@ -228,6 +229,16 @@ enum {
};
/*
+ * Values to determine clock to sample.
+ */
+enum perf_sample_clock_type {
+ /* Architecture-specific clock (TSC on x86) */
+ PERF_SAMPLE_CLOCK_ARCH = 0,
+
+ PERF_SAMPLE_CLOCK_MAX /* non-ABI */
+};
+
+/*
* The format of the data returned by read() on a perf event fd,
* as specified by attr.read_format:
*
@@ -328,7 +339,9 @@ struct perf_event_attr {
exclude_callchain_user : 1, /* exclude user
callchains */
mmap2 : 1, /* include mmap with inode
data */
comm_exec : 1, /* flag comm events that
are due to an exec */
- __reserved_1 : 39;
+ /* clock: see enum perf_sample_clock_type */
+ clock : 4, /* which clock */
+ __reserved_1 : 35;
union {
__u32 wakeup_events; /* wakeup every n events */
@@ -601,6 +614,7 @@ enum perf_event_type {
* { u64 id; } && PERF_SAMPLE_ID
* { u64 stream_id;} && PERF_SAMPLE_STREAM_ID
* { u32 cpu, res; } && PERF_SAMPLE_CPU
+ * { u64 clock; } && PERF_SAMPLE_CLOCK
* { u64 id; } && PERF_SAMPLE_IDENTIFIER
* } && perf_event_attr::sample_id_all
*
@@ -746,6 +760,7 @@ enum perf_event_type {
* { u64 transaction; } &&
PERF_SAMPLE_TRANSACTION
* { u64 abi; # enum perf_sample_regs_abi
* u64 regs[weight(mask)]; } &&
PERF_SAMPLE_REGS_INTR
+ * { u64 clock; } && PERF_SAMPLE_CLOCK
* };
*/
PERF_RECORD_SAMPLE = 9,
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 799f034..0f6e7c8 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1323,6 +1323,9 @@ static void perf_event__id_header_size(struct perf_event
*event)
if (sample_type & PERF_SAMPLE_CPU)
size += sizeof(data->cpu_entry);
+ if (sample_type & PERF_SAMPLE_CLOCK)
+ size += sizeof(data->clock);
+
event->id_header_size = size;
}
@@ -4915,6 +4918,11 @@ perf_output_sample_ustack(struct perf_output_handle
*handle, u64 dump_size,
}
}
+u64 __weak perf_sample_clock_arch(void)
+{
+ return 0;
+}
+
static void __perf_event_header__init_id(struct perf_event_header *header,
struct perf_sample_data *data,
struct perf_event *event)
@@ -4943,6 +4951,16 @@ static void __perf_event_header__init_id(struct
perf_event_header *header,
data->cpu_entry.cpu = raw_smp_processor_id();
data->cpu_entry.reserved = 0;
}
+
+ if (sample_type & PERF_SAMPLE_CLOCK) {
+ switch (event->attr.clock) {
+ case PERF_SAMPLE_CLOCK_ARCH:
+ data->clock = perf_sample_clock_arch();
+ break;
+ default:
+ data->clock = 0;
+ }
+ }
}
void perf_event_header__init_id(struct perf_event_header *header,
@@ -4973,6 +4991,9 @@ static void __perf_event__output_id_sample(struct
perf_output_handle *handle,
if (sample_type & PERF_SAMPLE_CPU)
perf_output_put(handle, data->cpu_entry);
+ if (sample_type & PERF_SAMPLE_CLOCK)
+ perf_output_put(handle, data->clock);
+
if (sample_type & PERF_SAMPLE_IDENTIFIER)
perf_output_put(handle, data->id);
}
@@ -5218,6 +5239,9 @@ void perf_output_sample(struct perf_output_handle *handle,
}
}
+ if (sample_type & PERF_SAMPLE_CLOCK)
+ perf_output_put(handle, data->clock);
+
if (!event->attr.watermark) {
int wakeup_events = event->attr.wakeup_events;
@@ -7632,6 +7656,12 @@ static int perf_copy_attr(struct perf_event_attr __user
*uattr,
if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
ret = perf_reg_validate(attr->sample_regs_intr);
+
+ if ((attr->sample_type & PERF_SAMPLE_CLOCK) &&
+ (attr->clock >= PERF_SAMPLE_CLOCK_MAX ||
+ (!HAVE_PERF_SAMPLE_CLOCK_ARCH &&
+ attr->clock == PERF_SAMPLE_CLOCK_ARCH)))
+ return -EINVAL;
out:
return ret;
diff --git a/kernel/events/internal.h b/kernel/events/internal.h
index 9f6ce9b..c3dca1e 100644
--- a/kernel/events/internal.h
+++ b/kernel/events/internal.h
@@ -228,4 +228,8 @@ static inline bool arch_perf_have_user_stack_dump(void)
#define perf_user_stack_pointer(regs) 0
#endif /* CONFIG_HAVE_PERF_USER_STACK_DUMP */
+#ifndef HAVE_PERF_SAMPLE_CLOCK_ARCH
+#define HAVE_PERF_SAMPLE_CLOCK_ARCH 0
+#endif
+
#endif /* _KERNEL_EVENTS_INTERNAL_H */
--
1.9.1
--
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