x86, perf_counter, bts: Optimize BTS overflow handling
Draining the BTS buffer on a buffer overflow interrupt takes too
long resulting in a kernel lockup when tracing the kernel.
Restructure perf_counter sampling into sample creation and sample
output.
Prepare a single reference sample for BTS sampling and update the
from and to address fields when draining the BTS buffer. Drain the
entire BTS buffer between a single perf_output_begin() /
perf_output_end() pair.
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20090915130023.A16204@sedona.ch.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index 6c1ef72..c7375f9 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -691,6 +691,17 @@
int recursion[4];
};
+struct perf_output_handle {
+ struct perf_counter *counter;
+ struct perf_mmap_data *data;
+ unsigned long head;
+ unsigned long offset;
+ int nmi;
+ int sample;
+ int locked;
+ unsigned long flags;
+};
+
#ifdef CONFIG_PERF_COUNTERS
/*
@@ -722,16 +733,38 @@
extern void perf_counter_update_userpage(struct perf_counter *counter);
struct perf_sample_data {
- struct pt_regs *regs;
+ u64 type;
+
+ u64 ip;
+ struct {
+ u32 pid;
+ u32 tid;
+ } tid_entry;
+ u64 time;
u64 addr;
+ u64 id;
+ u64 stream_id;
+ struct {
+ u32 cpu;
+ u32 reserved;
+ } cpu_entry;
u64 period;
+ struct perf_callchain_entry *callchain;
struct perf_raw_record *raw;
};
+extern void perf_output_sample(struct perf_output_handle *handle,
+ struct perf_event_header *header,
+ struct perf_sample_data *data,
+ struct perf_counter *counter);
+extern void perf_prepare_sample(struct perf_event_header *header,
+ struct perf_sample_data *data,
+ struct perf_counter *counter,
+ struct pt_regs *regs);
+
extern int perf_counter_overflow(struct perf_counter *counter, int nmi,
- struct perf_sample_data *data);
-extern void perf_counter_output(struct perf_counter *counter, int nmi,
- struct perf_sample_data *data);
+ struct perf_sample_data *data,
+ struct pt_regs *regs);
/*
* Return 1 for a software counter, 0 for a hardware counter
@@ -781,6 +814,12 @@
#define perf_instruction_pointer(regs) instruction_pointer(regs)
#endif
+extern int perf_output_begin(struct perf_output_handle *handle,
+ struct perf_counter *counter, unsigned int size,
+ int nmi, int sample);
+extern void perf_output_end(struct perf_output_handle *handle);
+extern void perf_output_copy(struct perf_output_handle *handle,
+ const void *buf, unsigned int len);
#else
static inline void
perf_counter_task_sched_in(struct task_struct *task, int cpu) { }
@@ -807,7 +846,28 @@
static inline void perf_counter_comm(struct task_struct *tsk) { }
static inline void perf_counter_fork(struct task_struct *tsk) { }
static inline void perf_counter_init(void) { }
+
+static inline int
+perf_output_begin(struct perf_output_handle *handle, struct perf_counter *c,
+ unsigned int size, int nmi, int sample) { }
+static inline void perf_output_end(struct perf_output_handle *handle) { }
+static inline void
+perf_output_copy(struct perf_output_handle *handle,
+ const void *buf, unsigned int len) { }
+static inline void
+perf_output_sample(struct perf_output_handle *handle,
+ struct perf_event_header *header,
+ struct perf_sample_data *data,
+ struct perf_counter *counter) { }
+static inline void
+perf_prepare_sample(struct perf_event_header *header,
+ struct perf_sample_data *data,
+ struct perf_counter *counter,
+ struct pt_regs *regs) { }
#endif
+#define perf_output_put(handle, x) \
+ perf_output_copy((handle), &(x), sizeof(x))
+
#endif /* __KERNEL__ */
#endif /* _LINUX_PERF_COUNTER_H */