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Commit ea5d20cf authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
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perf_counter: optionally provide the pid/tid of the sampled task 



Allow cpu wide counters to profile userspace by providing what process
the sample belongs to.

This raises the first issue with the output type, lots of these
options: group, tid, callchain, etc.. are non-exclusive and could be
combined, suggesting a bitfield.

However, things like the mmap() data stream doesn't fit in that.

How to split the type field...

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Orig-LKML-Reference: <20090325113317.013775235@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 63e35b25

include/linux/perf_counter.h

+4 −1
Original line number Diff line number Diff line
@@ -127,8 +127,9 @@ struct perf_counter_hw_event { 
				exclude_kernel :  1, /* ditto kernel          */

				exclude_hv     :  1, /* ditto hypervisor      */

				exclude_idle   :  1, /* don't count when idle */

				include_tid    :  1, /* include the tid */



				__reserved_1   : 55;

				__reserved_1   : 54;



	__u32			extra_config_len;

	__u32			__reserved_4;
@@ -164,6 +165,8 @@ struct perf_event_header { 
enum perf_event_type {

	PERF_EVENT_IP		= 0,

	PERF_EVENT_GROUP	= 1,



	__PERF_EVENT_TID	= 0x100,

};



#ifdef __KERNEL__

kernel/perf_counter.c

+16 −2
Original line number Diff line number Diff line
@@ -1528,16 +1528,30 @@ static int perf_output_write(struct perf_counter *counter, int nmi, 
static void perf_output_simple(struct perf_counter *counter,

			       int nmi, struct pt_regs *regs)

{

	unsigned int size;

	struct {

		struct perf_event_header header;

		u64 ip;

		u32 pid, tid;

	} event;



	event.header.type = PERF_EVENT_IP;

	event.header.size = sizeof(event);

	event.ip = instruction_pointer(regs);



	perf_output_write(counter, nmi, &event, sizeof(event));

	size = sizeof(event);



	if (counter->hw_event.include_tid) {

		/* namespace issues */

		event.pid = current->group_leader->pid;

		event.tid = current->pid;



		event.header.type |= __PERF_EVENT_TID;

	} else

		size -= sizeof(u64);



	event.header.size = size;



	perf_output_write(counter, nmi, &event, size);

}



static void perf_output_group(struct perf_counter *counter, int nmi)