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x86, perf_counter, bts: Optimize BTS overflow handling

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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>
This commit is contained in:
Markus Metzger 2009-09-15 13:00:23 +02:00 • committed by Ingo Molnar
parent 4b77a72977
commit 5622f295b5
3 changed files with 268 additions and 176 deletions
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68
include/linux/perf_counter.h
View file

@ -691,6 +691,17 @@ struct perf_cpu_context {
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 int hw_perf_group_sched_in(struct perf_counter *group_leader,
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 @@ extern void perf_tpcounter_event(int event_id, u64 addr, u64 count,
#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_mmap(struct vm_area_struct *vma) { }
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 */