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perf/trace: Add ability to set a target task for events 

A few events are interesting not only for a current task.
For example, sched_stat_* events are interesting for a task
which wakes up. For this reason, it will be good if such
events will be delivered to a target task too.

Now a target task can be set by using __perf_task().

The original idea and a draft patch belongs to Peter Zijlstra.

I need these events for profiling sleep times. sched_switch is used for
getting callchains and sched_stat_* is used for getting time periods.
These events are combined in user space, then it can be analyzed by
perf tools.

Inspired-by: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Arun Sharma <asharma@fb.com>
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1342016098-213063-1-git-send-email-avagin@openvz.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andrew Vagin 2012-07-11 18:14:58 +04:00 committed by Ingo Molnar
parent d07bdfd322
commit e6dab5ffab
11 changed files with 60 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
include/linux/ftrace_event.h
View File

@ -306,9 +306,10 @@ extern void *perf_trace_buf_prepare(int size, unsigned short type,
static inline void
perf_trace_buf_submit(void *raw_data, int size, int rctx, u64 addr,
u64 count, struct pt_regs *regs, void *head)
u64 count, struct pt_regs *regs, void *head,
struct task_struct *task)
{
perf_tp_event(addr, count, raw_data, size, regs, head, rctx);
perf_tp_event(addr, count, raw_data, size, regs, head, rctx, task);
}
#endif

3
include/linux/perf_event.h
View File

@ -1272,7 +1272,8 @@ static inline bool perf_paranoid_kernel(void)
extern void perf_event_init(void);
extern void perf_tp_event(u64 addr, u64 count, void *record,
int entry_size, struct pt_regs *regs,
struct hlist_head *head, int rctx);
struct hlist_head *head, int rctx,
struct task_struct *task);
extern void perf_bp_event(struct perf_event *event, void *data);
#ifndef perf_misc_flags

4
include/trace/events/sched.h
View File

@ -73,6 +73,9 @@ DECLARE_EVENT_CLASS(sched_wakeup_template,
__entry->prio = p->prio;
__entry->success = success;
__entry->target_cpu = task_cpu(p);
)
TP_perf_assign(
__perf_task(p);
),
TP_printk("comm=%s pid=%d prio=%d success=%d target_cpu=%03d",
@ -325,6 +328,7 @@ DECLARE_EVENT_CLASS(sched_stat_template,
)
TP_perf_assign(
__perf_count(delay);
__perf_task(tsk);
),
TP_printk("comm=%s pid=%d delay=%Lu [ns]",

6
include/trace/ftrace.h
View File

@ -712,6 +712,9 @@ __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call
#undef __perf_count
#define __perf_count(c) __count = (c)
#undef __perf_task
#define __perf_task(t) __task = (t)
#undef TP_perf_assign
#define TP_perf_assign(args...) args
@ -725,6 +728,7 @@ perf_trace_##call(void *__data, proto) \
struct ftrace_raw_##call *entry; \
struct pt_regs __regs; \
u64 __addr = 0, __count = 1; \
struct task_struct *__task = NULL; \
struct hlist_head *head; \
int __entry_size; \
int __data_size; \
@ -752,7 +756,7 @@ perf_trace_##call(void *__data, proto) \
\
head = this_cpu_ptr(event_call->perf_events); \
perf_trace_buf_submit(entry, __entry_size, rctx, __addr, \
__count, &__regs, head); \
__count, &__regs, head, __task); \
}
/*

9
kernel/events/callchain.c
View File

@ -153,7 +153,8 @@ put_callchain_entry(int rctx)
put_recursion_context(__get_cpu_var(callchain_recursion), rctx);
}
struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
struct perf_callchain_entry *
perf_callchain(struct perf_event *event, struct pt_regs *regs)
{
int rctx;
struct perf_callchain_entry *entry;
@ -178,6 +179,12 @@ struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
}
if (regs) {
/*
* Disallow cross-task user callchains.
*/
if (event->ctx->task && event->ctx->task != current)
goto exit_put;
perf_callchain_store(entry, PERF_CONTEXT_USER);
perf_callchain_user(entry, regs);
}

30
kernel/events/core.c
View File

@ -4039,7 +4039,7 @@ void perf_prepare_sample(struct perf_event_header *header,
if (sample_type & PERF_SAMPLE_CALLCHAIN) {
int size = 1;
data->callchain = perf_callchain(regs);
data->callchain = perf_callchain(event, regs);
if (data->callchain)
size += data->callchain->nr;
@ -5209,7 +5209,8 @@ static int perf_tp_event_match(struct perf_event *event,
}
void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
struct pt_regs *regs, struct hlist_head *head, int rctx)
struct pt_regs *regs, struct hlist_head *head, int rctx,
struct task_struct *task)
{
struct perf_sample_data data;
struct perf_event *event;
@ -5228,6 +5229,31 @@ void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
perf_swevent_event(event, count, &data, regs);
}
/*
* If we got specified a target task, also iterate its context and
* deliver this event there too.
*/
if (task && task != current) {
struct perf_event_context *ctx;
struct trace_entry *entry = record;
rcu_read_lock();
ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
if (!ctx)
goto unlock;
list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
if (event->attr.type != PERF_TYPE_TRACEPOINT)
continue;
if (event->attr.config != entry->type)
continue;
if (perf_tp_event_match(event, &data, regs))
perf_swevent_event(event, count, &data, regs);
}
unlock:
rcu_read_unlock();
}
perf_swevent_put_recursion_context(rctx);
}
EXPORT_SYMBOL_GPL(perf_tp_event);

3
kernel/events/internal.h
View File

@ -101,7 +101,8 @@ __output_copy(struct perf_output_handle *handle,
}
/* Callchain handling */
extern struct perf_callchain_entry *perf_callchain(struct pt_regs *regs);
extern struct perf_callchain_entry *
perf_callchain(struct perf_event *event, struct pt_regs *regs);
extern int get_callchain_buffers(void);
extern void put_callchain_buffers(void);

2
kernel/trace/trace_event_perf.c
View File

@ -281,7 +281,7 @@ perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip)
head = this_cpu_ptr(event_function.perf_events);
perf_trace_buf_submit(entry, ENTRY_SIZE, rctx, 0,
1, &regs, head);
1, &regs, head, NULL);
#undef ENTRY_SIZE
}

6
kernel/trace/trace_kprobe.c
View File

@ -1002,7 +1002,8 @@ static __kprobes void kprobe_perf_func(struct kprobe *kp,
store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
head = this_cpu_ptr(call->perf_events);
perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head);
perf_trace_buf_submit(entry, size, rctx,
entry->ip, 1, regs, head, NULL);
}
/* Kretprobe profile handler */
@ -1033,7 +1034,8 @@ static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
head = this_cpu_ptr(call->perf_events);
perf_trace_buf_submit(entry, size, rctx, entry->ret_ip, 1, regs, head);
perf_trace_buf_submit(entry, size, rctx,
entry->ret_ip, 1, regs, head, NULL);
}
#endif /* CONFIG_PERF_EVENTS */

4
kernel/trace/trace_syscalls.c
View File

@ -532,7 +532,7 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
(unsigned long *)&rec->args);
head = this_cpu_ptr(sys_data->enter_event->perf_events);
perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head);
perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head, NULL);
}
int perf_sysenter_enable(struct ftrace_event_call *call)
@ -608,7 +608,7 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
rec->ret = syscall_get_return_value(current, regs);
head = this_cpu_ptr(sys_data->exit_event->perf_events);
perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head);
perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head, NULL);
}
int perf_sysexit_enable(struct ftrace_event_call *call)

2
kernel/trace/trace_uprobe.c
View File

@ -670,7 +670,7 @@ static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
head = this_cpu_ptr(call->perf_events);
perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head);
perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, regs, head, NULL);
out:
preempt_enable();