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perf_counter: track task-comm data

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Similar to the mmap data stream, add one that tracks the task COMM field,
so that the userspace reporting knows what to call a task.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <20090408130409.127422406@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2009-04-08 15:01:30 +02:00 committed by Ingo Molnar
parent 8740f9418c
commit 8d1b2d9361
3 changed files with 109 additions and 1 deletions
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1
fs/exec.c
View file

@ -951,6 +951,7 @@ void set_task_comm(struct task_struct *tsk, char *buf)
task_lock(tsk);
strlcpy(tsk->comm, buf, sizeof(tsk->comm));
task_unlock(tsk);
perf_counter_comm(tsk);
}
int flush_old_exec(struct linux_binprm * bprm)

16
include/linux/perf_counter.h
View file

@ -142,8 +142,9 @@ struct perf_counter_hw_event {
exclude_idle : 1, /* don't count when idle */
mmap : 1, /* include mmap data */
munmap : 1, /* include munmap data */
comm : 1, /* include comm data */
__reserved_1 : 53;
__reserved_1 : 52;
__u32 extra_config_len;
__u32 wakeup_events; /* wakeup every n events */
@ -230,6 +231,16 @@ enum perf_event_type {
PERF_EVENT_MMAP = 1,
PERF_EVENT_MUNMAP = 2,
/*
* struct {
* struct perf_event_header header;
*
* u32 pid, tid;
* char comm[];
* };
*/
PERF_EVENT_COMM = 3,
/*
* When header.misc & PERF_EVENT_MISC_OVERFLOW the event_type field
* will be PERF_RECORD_*
@ -545,6 +556,8 @@ 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);
extern void perf_counter_comm(struct task_struct *tsk);
#define MAX_STACK_DEPTH 255
struct perf_callchain_entry {
@ -583,6 +596,7 @@ static inline void
perf_counter_munmap(unsigned long addr, unsigned long len,
unsigned long pgoff, struct file *file) { }
static inline void perf_counter_comm(struct task_struct *tsk) { }
#endif
#endif /* __KERNEL__ */

93
kernel/perf_counter.c
View file

@ -1916,6 +1916,99 @@ static void perf_counter_output(struct perf_counter *counter,
perf_output_end(&handle);
}
/*
* comm tracking
*/
struct perf_comm_event {
struct task_struct *task;
char *comm;
int comm_size;
struct {
struct perf_event_header header;
u32 pid;
u32 tid;
} event;
};
static void perf_counter_comm_output(struct perf_counter *counter,
struct perf_comm_event *comm_event)
{
struct perf_output_handle handle;
int size = comm_event->event.header.size;
int ret = perf_output_begin(&handle, counter, size, 0, 0);
if (ret)
return;
perf_output_put(&handle, comm_event->event);
perf_output_copy(&handle, comm_event->comm,
comm_event->comm_size);
perf_output_end(&handle);
}
static int perf_counter_comm_match(struct perf_counter *counter,
struct perf_comm_event *comm_event)
{
if (counter->hw_event.comm &&
comm_event->event.header.type == PERF_EVENT_COMM)
return 1;
return 0;
}
static void perf_counter_comm_ctx(struct perf_counter_context *ctx,
struct perf_comm_event *comm_event)
{
struct perf_counter *counter;
if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
return;
rcu_read_lock();
list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
if (perf_counter_comm_match(counter, comm_event))
perf_counter_comm_output(counter, comm_event);
}
rcu_read_unlock();
}
static void perf_counter_comm_event(struct perf_comm_event *comm_event)
{
struct perf_cpu_context *cpuctx;
unsigned int size;
char *comm = comm_event->task->comm;
size = ALIGN(strlen(comm), sizeof(u64));
comm_event->comm = comm;
comm_event->comm_size = size;
comm_event->event.header.size = sizeof(comm_event->event) + size;
cpuctx = &get_cpu_var(perf_cpu_context);
perf_counter_comm_ctx(&cpuctx->ctx, comm_event);
put_cpu_var(perf_cpu_context);
perf_counter_comm_ctx(&current->perf_counter_ctx, comm_event);
}
void perf_counter_comm(struct task_struct *task)
{
struct perf_comm_event comm_event = {
.task = task,
.event = {
.header = { .type = PERF_EVENT_COMM, },
.pid = task->group_leader->pid,
.tid = task->pid,
},
};
perf_counter_comm_event(&comm_event);
}
/*
* mmap tracking
*/