[tip:perf/core] perf/ftrace: Optimize perf/tracepoint interaction for single events

From: tip-bot for Peter Zijlstra
Date: Tue May 18 2010 - 13:16:29 EST

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Commit-ID: 4f41c013f553957765902fb01475972f0af3e8e7
Gitweb: http://git.kernel.org/tip/4f41c013f553957765902fb01475972f0af3e8e7
Author: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
AuthorDate: Tue, 18 May 2010 18:08:32 +0200
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Tue, 18 May 2010 18:35:46 +0200

perf/ftrace: Optimize perf/tracepoint interaction for single events

When we've got but a single event per tracepoint
there is no reason to try and multiplex it so don't.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Tested-by: Ingo Molnar <mingo@xxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
include/linux/ftrace_event.h | 8 +++++---
include/linux/perf_event.h | 2 +-
include/trace/ftrace.h | 3 ++-
kernel/perf_event.c | 15 ++++++++++-----
kernel/trace/trace_event_perf.c | 11 +++++++----
kernel/trace/trace_kprobe.c | 4 ++--
kernel/trace/trace_syscalls.c | 6 ++++--
7 files changed, 31 insertions(+), 18 deletions(-)

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index c0f4b36..c809100 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -132,6 +132,7 @@ struct ftrace_event_call {
void *data;

int perf_refcount;
+ void *perf_data;
int (*perf_event_enable)(struct ftrace_event_call *);
void (*perf_event_disable)(struct ftrace_event_call *);
};
@@ -190,7 +191,7 @@ struct perf_event;

DECLARE_PER_CPU(struct pt_regs, perf_trace_regs);

-extern int perf_trace_enable(int event_id);
+extern int perf_trace_enable(int event_id, void *data);
extern void perf_trace_disable(int event_id);
extern int ftrace_profile_set_filter(struct perf_event *event, int event_id,
char *filter_str);
@@ -201,11 +202,12 @@ perf_trace_buf_prepare(int size, unsigned short type, int *rctxp,

static inline void
perf_trace_buf_submit(void *raw_data, int size, int rctx, u64 addr,
- u64 count, unsigned long irq_flags, struct pt_regs *regs)
+ u64 count, unsigned long irq_flags, struct pt_regs *regs,
+ void *event)
{
struct trace_entry *entry = raw_data;

- perf_tp_event(entry->type, addr, count, raw_data, size, regs);
+ perf_tp_event(entry->type, addr, count, raw_data, size, regs, event);
perf_swevent_put_recursion_context(rctx);
local_irq_restore(irq_flags);
}
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 3fd5c82..0b521fc 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -994,7 +994,7 @@ static inline bool perf_paranoid_kernel(void)

extern void perf_event_init(void);
extern void perf_tp_event(int event_id, u64 addr, u64 count, void *record,
- int entry_size, struct pt_regs *regs);
+ int entry_size, struct pt_regs *regs, void *event);
extern void perf_bp_event(struct perf_event *event, void *data);

#ifndef perf_misc_flags
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 882c648..0a29df0 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -785,7 +785,8 @@ perf_trace_templ_##call(struct ftrace_event_call *event_call, \
{ assign; } \
\
perf_trace_buf_submit(entry, __entry_size, rctx, __addr, \
- __count, irq_flags, __regs); \
+ __count, irq_flags, __regs, \
+ event_call->perf_data); \
}

#undef DEFINE_EVENT
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index a4fa381..17ac47f 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -4468,8 +4468,9 @@ static int swevent_hlist_get(struct perf_event *event)
#ifdef CONFIG_EVENT_TRACING

void perf_tp_event(int event_id, u64 addr, u64 count, void *record,
- int entry_size, struct pt_regs *regs)
+ int entry_size, struct pt_regs *regs, void *event)
{
+ const int type = PERF_TYPE_TRACEPOINT;
struct perf_sample_data data;
struct perf_raw_record raw = {
.size = entry_size,
@@ -4479,9 +4480,13 @@ void perf_tp_event(int event_id, u64 addr, u64 count, void *record,
perf_sample_data_init(&data, addr);
data.raw = &raw;

- /* Trace events already protected against recursion */
- do_perf_sw_event(PERF_TYPE_TRACEPOINT, event_id, count, 1,
- &data, regs);
+ if (!event) {
+ do_perf_sw_event(type, event_id, count, 1, &data, regs);
+ return;
+ }
+
+ if (perf_swevent_match(event, type, event_id, &data, regs))
+ perf_swevent_add(event, count, 1, &data, regs);
}
EXPORT_SYMBOL_GPL(perf_tp_event);

@@ -4514,7 +4519,7 @@ static const struct pmu *tp_perf_event_init(struct perf_event *event)
!capable(CAP_SYS_ADMIN))
return ERR_PTR(-EPERM);

- if (perf_trace_enable(event->attr.config))
+ if (perf_trace_enable(event->attr.config, event))
return NULL;

event->destroy = tp_perf_event_destroy;
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 0565bb4..89b780a 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -27,13 +27,15 @@ typedef typeof(unsigned long [PERF_MAX_TRACE_SIZE / sizeof(unsigned long)])
/* Count the events in use (per event id, not per instance) */
static int total_ref_count;

-static int perf_trace_event_enable(struct ftrace_event_call *event)
+static int perf_trace_event_enable(struct ftrace_event_call *event, void *data)
{
char *buf;
int ret = -ENOMEM;

- if (event->perf_refcount++ > 0)
+ if (event->perf_refcount++ > 0) {
+ event->perf_data = NULL;
return 0;
+ }

if (!total_ref_count) {
buf = (char *)alloc_percpu(perf_trace_t);
@@ -51,6 +53,7 @@ static int perf_trace_event_enable(struct ftrace_event_call *event)

ret = event->perf_event_enable(event);
if (!ret) {
+ event->perf_data = data;
total_ref_count++;
return 0;
}
@@ -68,7 +71,7 @@ fail_buf:
return ret;
}

-int perf_trace_enable(int event_id)
+int perf_trace_enable(int event_id, void *data)
{
struct ftrace_event_call *event;
int ret = -EINVAL;
@@ -77,7 +80,7 @@ int perf_trace_enable(int event_id)
list_for_each_entry(event, &ftrace_events, list) {
if (event->id == event_id && event->perf_event_enable &&
try_module_get(event->mod)) {
- ret = perf_trace_event_enable(event);
+ ret = perf_trace_event_enable(event, data);
break;
}
}
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index a751432..2d7bf41 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1362,7 +1362,7 @@ static __kprobes void kprobe_perf_func(struct kprobe *kp,
for (i = 0; i < tp->nr_args; i++)
call_fetch(&tp->args[i].fetch, regs, data + tp->args[i].offset);

- perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, irq_flags, regs);
+ perf_trace_buf_submit(entry, size, rctx, entry->ip, 1, irq_flags, regs, call->perf_data);
}

/* Kretprobe profile handler */
@@ -1395,7 +1395,7 @@ static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
call_fetch(&tp->args[i].fetch, regs, data + tp->args[i].offset);

perf_trace_buf_submit(entry, size, rctx, entry->ret_ip, 1,
- irq_flags, regs);
+ irq_flags, regs, call->perf_data);
}

static int probe_perf_enable(struct ftrace_event_call *call)
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 4d6d711..9eff1a4 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -468,7 +468,8 @@ static void perf_syscall_enter(struct pt_regs *regs, long id)
rec->nr = syscall_nr;
syscall_get_arguments(current, regs, 0, sys_data->nb_args,
(unsigned long *)&rec->args);
- perf_trace_buf_submit(rec, size, rctx, 0, 1, flags, regs);
+ perf_trace_buf_submit(rec, size, rctx, 0, 1, flags, regs,
+ sys_data->enter_event->perf_data);
}

int perf_sysenter_enable(struct ftrace_event_call *call)
@@ -543,7 +544,8 @@ static void perf_syscall_exit(struct pt_regs *regs, long ret)
rec->nr = syscall_nr;
rec->ret = syscall_get_return_value(current, regs);

- perf_trace_buf_submit(rec, size, rctx, 0, 1, flags, regs);
+ perf_trace_buf_submit(rec, size, rctx, 0, 1, flags, regs,
+ sys_data->exit_event->perf_data);
}

int perf_sysexit_enable(struct ftrace_event_call *call)
--
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Next message: tip-bot for Peter Zijlstra: "[tip:perf/core] perf: Optimize buffer placement by allocating buffers NUMA aware"
Previous message: Srikar Dronamraju: "[PATCH v4 5/13] Slot allocation for execution out of line (XOL)"
Next in thread: Frederic Weisbecker: "Re: [tip:perf/core] perf/ftrace: Optimize perf/tracepointinteraction for single events"
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