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perf_counter: provide generic callchain bits

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Provide the generic callchain support bits. If hw_event->callchain is
set the arch specific perf_callchain() function is called upon to
provide a perf_callchain_entry structure filled with the current
callchain.

If it does so, it is added to the overflow output event.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Paul Mackerras <paulus@samba.org>
Orig-LKML-Reference: <20090330171024.254266860@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2009-03-30 19:07:14 +02:00 committed by Ingo Molnar
parent 023c54c422
commit 394ee07623
2 changed files with 39 additions and 1 deletions
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13
include/linux/perf_counter.h
View file

@ -140,8 +140,9 @@ struct perf_counter_hw_event {
include_tid : 1, /* include the tid */
mmap : 1, /* include mmap data */
munmap : 1, /* include munmap data */
callchain : 1, /* add callchain data */
__reserved_1 : 52;
__reserved_1 : 51;
__u32 extra_config_len;
__u32 __reserved_4;
@ -219,6 +220,7 @@ enum perf_event_type {
PERF_EVENT_OVERFLOW = 1UL << 31,
__PERF_EVENT_IP = 1UL << 30,
__PERF_EVENT_TID = 1UL << 29,
__PERF_EVENT_CALLCHAIN = 1UL << 28,
};
#ifdef __KERNEL__
@ -504,6 +506,15 @@ extern void perf_counter_mmap(unsigned long addr, unsigned long len,
extern void perf_counter_munmap(unsigned long addr, unsigned long len,
unsigned long pgoff, struct file *file);
#define MAX_STACK_DEPTH 255
struct perf_callchain_entry {
u64 nr;
u64 ip[MAX_STACK_DEPTH];
};
extern struct perf_callchain_entry *perf_callchain(struct pt_regs *regs);
#else
static inline void
perf_counter_task_sched_in(struct task_struct *task, int cpu) { }

27
kernel/perf_counter.c
View file

@ -1653,6 +1653,17 @@ void perf_counter_do_pending(void)
__perf_pending_run();
}
/*
* Callchain support -- arch specific
*/
struct perf_callchain_entry *
__attribute__((weak))
perf_callchain(struct pt_regs *regs)
{
return NULL;
}
/*
* Output
*/
@ -1764,6 +1775,8 @@ static void perf_output_simple(struct perf_counter *counter,
struct {
u32 pid, tid;
} tid_entry;
struct perf_callchain_entry *callchain = NULL;
int callchain_size = 0;
header.type = PERF_EVENT_OVERFLOW;
header.size = sizeof(header);
@ -1781,6 +1794,17 @@ static void perf_output_simple(struct perf_counter *counter,
header.size += sizeof(tid_entry);
}
if (counter->hw_event.callchain) {
callchain = perf_callchain(regs);
if (callchain) {
callchain_size = (1 + callchain->nr) * sizeof(u64);
header.type |= __PERF_EVENT_CALLCHAIN;
header.size += callchain_size;
}
}
ret = perf_output_begin(&handle, counter, header.size, nmi);
if (ret)
return;
@ -1791,6 +1815,9 @@ static void perf_output_simple(struct perf_counter *counter,
if (counter->hw_event.include_tid)
perf_output_put(&handle, tid_entry);
if (callchain)
perf_output_copy(&handle, callchain, callchain_size);
perf_output_end(&handle);
}