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tracing: Add kprobes event profiling interface

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Add profiling interfaces for each kprobes event. This interface provides
how many times each probe hit or missed.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Przemysław Pawełczyk <przemyslaw@pawelczyk.it>
Cc: Roland McGrath <roland@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
LKML-Reference: <20090813203541.31965.8452.stgit@localhost.localdomain>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
This commit is contained in:
Masami Hiramatsu 2009-08-13 16:35:42 -04:00 committed by Frederic Weisbecker
parent ff50d99136
commit cd7e7bd5e4
2 changed files with 51 additions and 0 deletions
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8
Documentation/trace/kprobetrace.txt
View file

@ -70,6 +70,14 @@ filter:
names and field names for describing filters.
Event Profiling
---------------
You can check the total number of probe hits and probe miss-hits via
/sys/kernel/debug/tracing/kprobe_profile.
The first column is event name, the second is the number of probe hits,
the third is the number of probe miss-hits.
Usage examples
--------------
To add a probe as a new event, write a new definition to kprobe_events

43
kernel/trace/trace_kprobe.c
View file

@ -184,6 +184,7 @@ struct trace_probe {
struct kprobe kp;
struct kretprobe rp;
};
unsigned long nhit;
const char *symbol; /* symbol name */
struct ftrace_event_call call;
struct trace_event event;
@ -781,6 +782,37 @@ static const struct file_operations kprobe_events_ops = {
.write = probes_write,
};
/* Probes profiling interfaces */
static int probes_profile_seq_show(struct seq_file *m, void *v)
{
struct trace_probe *tp = v;
seq_printf(m, " %-44s %15lu %15lu\n", tp->call.name, tp->nhit,
probe_is_return(tp) ? tp->rp.kp.nmissed : tp->kp.nmissed);
return 0;
}
static const struct seq_operations profile_seq_op = {
.start = probes_seq_start,
.next = probes_seq_next,
.stop = probes_seq_stop,
.show = probes_profile_seq_show
};
static int profile_open(struct inode *inode, struct file *file)
{
return seq_open(file, &profile_seq_op);
}
static const struct file_operations kprobe_profile_ops = {
.owner = THIS_MODULE,
.open = profile_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
/* Kprobe handler */
static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
{
@ -791,6 +823,8 @@ static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
unsigned long irq_flags;
struct ftrace_event_call *call = &tp->call;
tp->nhit++;
local_save_flags(irq_flags);
pc = preempt_count();
@ -1140,9 +1174,18 @@ static __init int init_kprobe_trace(void)
entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
NULL, &kprobe_events_ops);
/* Event list interface */
if (!entry)
pr_warning("Could not create debugfs "
"'kprobe_events' entry\n");
/* Profile interface */
entry = debugfs_create_file("kprobe_profile", 0444, d_tracer,
NULL, &kprobe_profile_ops);
if (!entry)
pr_warning("Could not create debugfs "
"'kprobe_profile' entry\n");
return 0;
}
fs_initcall(init_kprobe_trace);