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perf_counter: optionally provide the pid/tid of the sampled task

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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: Peter 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: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2009-03-25 12:30:25 +01:00 committed by Ingo Molnar
parent 63e35b25d6
commit ea5d20cf99
2 changed files with 20 additions and 3 deletions
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5
include/linux/perf_counter.h
View File

@ -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__

18
kernel/perf_counter.c
View File

@ -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)