Commit 394ee076 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

perf_counter: provide generic callchain bits 



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: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: default avatarPaul Mackerras <paulus@samba.org>
Orig-LKML-Reference: <20090330171024.254266860@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 023c54c4

include/linux/perf_counter.h

+12 −1
Original line number Diff line number Diff line
@@ -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)		{ }

kernel/perf_counter.c

+27 −0
Original line number Diff line number Diff line
@@ -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);

}

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