Commit f7355a5e authored by Ingo Molnar's avatar Ingo Molnar

Merge branch 'tip/perf/core' of...

Merge branch 'tip/perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into perf/core

Pull tracing updated from Steve Rostedt.
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parents 9c4c5fd9 d840f718
...@@ -1842,6 +1842,89 @@ an error. ...@@ -1842,6 +1842,89 @@ an error.
# cat buffer_size_kb # cat buffer_size_kb
85 85
Snapshot
--------
CONFIG_TRACER_SNAPSHOT makes a generic snapshot feature
available to all non latency tracers. (Latency tracers which
record max latency, such as "irqsoff" or "wakeup", can't use
this feature, since those are already using the snapshot
mechanism internally.)
Snapshot preserves a current trace buffer at a particular point
in time without stopping tracing. Ftrace swaps the current
buffer with a spare buffer, and tracing continues in the new
current (=previous spare) buffer.
The following debugfs files in "tracing" are related to this
feature:
snapshot:
This is used to take a snapshot and to read the output
of the snapshot. Echo 1 into this file to allocate a
spare buffer and to take a snapshot (swap), then read
the snapshot from this file in the same format as
"trace" (described above in the section "The File
System"). Both reads snapshot and tracing are executable
in parallel. When the spare buffer is allocated, echoing
0 frees it, and echoing else (positive) values clear the
snapshot contents.
More details are shown in the table below.
status\input | 0 | 1 | else |
--------------+------------+------------+------------+
not allocated |(do nothing)| alloc+swap | EINVAL |
--------------+------------+------------+------------+
allocated | free | swap | clear |
--------------+------------+------------+------------+
Here is an example of using the snapshot feature.
# echo 1 > events/sched/enable
# echo 1 > snapshot
# cat snapshot
# tracer: nop
#
# entries-in-buffer/entries-written: 71/71 #P:8
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / delay
# TASK-PID CPU# |||| TIMESTAMP FUNCTION
# | | | |||| | |
<idle>-0 [005] d... 2440.603828: sched_switch: prev_comm=swapper/5 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=snapshot-test-2 next_pid=2242 next_prio=120
sleep-2242 [005] d... 2440.603846: sched_switch: prev_comm=snapshot-test-2 prev_pid=2242 prev_prio=120 prev_state=R ==> next_comm=kworker/5:1 next_pid=60 next_prio=120
[...]
<idle>-0 [002] d... 2440.707230: sched_switch: prev_comm=swapper/2 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=snapshot-test-2 next_pid=2229 next_prio=120
# cat trace
# tracer: nop
#
# entries-in-buffer/entries-written: 77/77 #P:8
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / delay
# TASK-PID CPU# |||| TIMESTAMP FUNCTION
# | | | |||| | |
<idle>-0 [007] d... 2440.707395: sched_switch: prev_comm=swapper/7 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=snapshot-test-2 next_pid=2243 next_prio=120
snapshot-test-2-2229 [002] d... 2440.707438: sched_switch: prev_comm=snapshot-test-2 prev_pid=2229 prev_prio=120 prev_state=S ==> next_comm=swapper/2 next_pid=0 next_prio=120
[...]
If you try to use this snapshot feature when current tracer is
one of the latency tracers, you will get the following results.
# echo wakeup > current_tracer
# echo 1 > snapshot
bash: echo: write error: Device or resource busy
# cat snapshot
cat: snapshot: Device or resource busy
----------- -----------
More details can be found in the source code, in the More details can be found in the source code, in the
......
...@@ -83,6 +83,9 @@ struct trace_iterator { ...@@ -83,6 +83,9 @@ struct trace_iterator {
long idx; long idx;
cpumask_var_t started; cpumask_var_t started;
/* it's true when current open file is snapshot */
bool snapshot;
}; };
enum trace_iter_flags { enum trace_iter_flags {
......
...@@ -167,6 +167,7 @@ unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu); ...@@ -167,6 +167,7 @@ unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu);
unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu); unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu);
unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu); unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu);
unsigned long ring_buffer_dropped_events_cpu(struct ring_buffer *buffer, int cpu); unsigned long ring_buffer_dropped_events_cpu(struct ring_buffer *buffer, int cpu);
unsigned long ring_buffer_read_events_cpu(struct ring_buffer *buffer, int cpu);
u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu); u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu);
void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer, void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer,
......
...@@ -253,6 +253,16 @@ config FTRACE_SYSCALLS ...@@ -253,6 +253,16 @@ config FTRACE_SYSCALLS
help help
Basic tracer to catch the syscall entry and exit events. Basic tracer to catch the syscall entry and exit events.
config TRACER_SNAPSHOT
bool "Create a snapshot trace buffer"
select TRACER_MAX_TRACE
help
Allow tracing users to take snapshot of the current buffer using the
ftrace interface, e.g.:
echo 1 > /sys/kernel/debug/tracing/snapshot
cat snapshot
config TRACE_BRANCH_PROFILING config TRACE_BRANCH_PROFILING
bool bool
select GENERIC_TRACER select GENERIC_TRACER
......
...@@ -3102,6 +3102,24 @@ ring_buffer_dropped_events_cpu(struct ring_buffer *buffer, int cpu) ...@@ -3102,6 +3102,24 @@ ring_buffer_dropped_events_cpu(struct ring_buffer *buffer, int cpu)
} }
EXPORT_SYMBOL_GPL(ring_buffer_dropped_events_cpu); EXPORT_SYMBOL_GPL(ring_buffer_dropped_events_cpu);
/**
* ring_buffer_read_events_cpu - get the number of events successfully read
* @buffer: The ring buffer
* @cpu: The per CPU buffer to get the number of events read
*/
unsigned long
ring_buffer_read_events_cpu(struct ring_buffer *buffer, int cpu)
{
struct ring_buffer_per_cpu *cpu_buffer;
if (!cpumask_test_cpu(cpu, buffer->cpumask))
return 0;
cpu_buffer = buffer->buffers[cpu];
return cpu_buffer->read;
}
EXPORT_SYMBOL_GPL(ring_buffer_read_events_cpu);
/** /**
* ring_buffer_entries - get the number of entries in a buffer * ring_buffer_entries - get the number of entries in a buffer
* @buffer: The ring buffer * @buffer: The ring buffer
......
This diff is collapsed.
...@@ -287,6 +287,7 @@ struct tracer { ...@@ -287,6 +287,7 @@ struct tracer {
struct tracer_flags *flags; struct tracer_flags *flags;
bool print_max; bool print_max;
bool use_max_tr; bool use_max_tr;
bool allocated_snapshot;
}; };
......
...@@ -84,7 +84,7 @@ u64 notrace trace_clock_global(void) ...@@ -84,7 +84,7 @@ u64 notrace trace_clock_global(void)
local_irq_save(flags); local_irq_save(flags);
this_cpu = raw_smp_processor_id(); this_cpu = raw_smp_processor_id();
now = cpu_clock(this_cpu); now = sched_clock_cpu(this_cpu);
/* /*
* If in an NMI context then dont risk lockups and return the * If in an NMI context then dont risk lockups and return the
* cpu_clock() time: * cpu_clock() time:
......
...@@ -191,10 +191,16 @@ unsigned long ftrace_return_to_handler(unsigned long frame_pointer) ...@@ -191,10 +191,16 @@ unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
ftrace_pop_return_trace(&trace, &ret, frame_pointer); ftrace_pop_return_trace(&trace, &ret, frame_pointer);
trace.rettime = trace_clock_local(); trace.rettime = trace_clock_local();
ftrace_graph_return(&trace);
barrier(); barrier();
current->curr_ret_stack--; current->curr_ret_stack--;
/*
* The trace should run after decrementing the ret counter
* in case an interrupt were to come in. We don't want to
* lose the interrupt if max_depth is set.
*/
ftrace_graph_return(&trace);
if (unlikely(!ret)) { if (unlikely(!ret)) {
ftrace_graph_stop(); ftrace_graph_stop();
WARN_ON(1); WARN_ON(1);
......
...@@ -5,12 +5,6 @@ menuconfig SAMPLES ...@@ -5,12 +5,6 @@ menuconfig SAMPLES
if SAMPLES if SAMPLES
config SAMPLE_TRACEPOINTS
tristate "Build tracepoints examples -- loadable modules only"
depends on TRACEPOINTS && m
help
This build tracepoints example modules.
config SAMPLE_TRACE_EVENTS config SAMPLE_TRACE_EVENTS
tristate "Build trace_events examples -- loadable modules only" tristate "Build trace_events examples -- loadable modules only"
depends on EVENT_TRACING && m depends on EVENT_TRACING && m
......
# Makefile for Linux samples code # Makefile for Linux samples code
obj-$(CONFIG_SAMPLES) += kobject/ kprobes/ tracepoints/ trace_events/ \ obj-$(CONFIG_SAMPLES) += kobject/ kprobes/ trace_events/ \
hw_breakpoint/ kfifo/ kdb/ hidraw/ rpmsg/ seccomp/ hw_breakpoint/ kfifo/ kdb/ hidraw/ rpmsg/ seccomp/
# builds the tracepoint example kernel modules;
# then to use one (as root): insmod <module_name.ko>
obj-$(CONFIG_SAMPLE_TRACEPOINTS) += tracepoint-sample.o
obj-$(CONFIG_SAMPLE_TRACEPOINTS) += tracepoint-probe-sample.o
obj-$(CONFIG_SAMPLE_TRACEPOINTS) += tracepoint-probe-sample2.o
#ifndef _TP_SAMPLES_TRACE_H
#define _TP_SAMPLES_TRACE_H
#include <linux/proc_fs.h> /* for struct inode and struct file */
#include <linux/tracepoint.h>
DECLARE_TRACE(subsys_event,
TP_PROTO(struct inode *inode, struct file *file),
TP_ARGS(inode, file));
DECLARE_TRACE_NOARGS(subsys_eventb);
#endif
/*
* tracepoint-probe-sample.c
*
* sample tracepoint probes.
*/
#include <linux/module.h>
#include <linux/file.h>
#include <linux/dcache.h>
#include "tp-samples-trace.h"
/*
* Here the caller only guarantees locking for struct file and struct inode.
* Locking must therefore be done in the probe to use the dentry.
*/
static void probe_subsys_event(void *ignore,
struct inode *inode, struct file *file)
{
path_get(&file->f_path);
dget(file->f_path.dentry);
printk(KERN_INFO "Event is encountered with filename %s\n",
file->f_path.dentry->d_name.name);
dput(file->f_path.dentry);
path_put(&file->f_path);
}
static void probe_subsys_eventb(void *ignore)
{
printk(KERN_INFO "Event B is encountered\n");
}
static int __init tp_sample_trace_init(void)
{
int ret;
ret = register_trace_subsys_event(probe_subsys_event, NULL);
WARN_ON(ret);
ret = register_trace_subsys_eventb(probe_subsys_eventb, NULL);
WARN_ON(ret);
return 0;
}
module_init(tp_sample_trace_init);
static void __exit tp_sample_trace_exit(void)
{
unregister_trace_subsys_eventb(probe_subsys_eventb, NULL);
unregister_trace_subsys_event(probe_subsys_event, NULL);
tracepoint_synchronize_unregister();
}
module_exit(tp_sample_trace_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("Tracepoint Probes Samples");
/*
* tracepoint-probe-sample2.c
*
* 2nd sample tracepoint probes.
*/
#include <linux/module.h>
#include <linux/fs.h>
#include "tp-samples-trace.h"
/*
* Here the caller only guarantees locking for struct file and struct inode.
* Locking must therefore be done in the probe to use the dentry.
*/
static void probe_subsys_event(void *ignore,
struct inode *inode, struct file *file)
{
printk(KERN_INFO "Event is encountered with inode number %lu\n",
inode->i_ino);
}
static int __init tp_sample_trace_init(void)
{
int ret;
ret = register_trace_subsys_event(probe_subsys_event, NULL);
WARN_ON(ret);
return 0;
}
module_init(tp_sample_trace_init);
static void __exit tp_sample_trace_exit(void)
{
unregister_trace_subsys_event(probe_subsys_event, NULL);
tracepoint_synchronize_unregister();
}
module_exit(tp_sample_trace_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("Tracepoint Probes Samples");
/* tracepoint-sample.c
*
* Executes a tracepoint when /proc/tracepoint-sample is opened.
*
* (C) Copyright 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
*
* This file is released under the GPLv2.
* See the file COPYING for more details.
*/
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/proc_fs.h>
#include "tp-samples-trace.h"
DEFINE_TRACE(subsys_event);
DEFINE_TRACE(subsys_eventb);
struct proc_dir_entry *pentry_sample;
static int my_open(struct inode *inode, struct file *file)
{
int i;
trace_subsys_event(inode, file);
for (i = 0; i < 10; i++)
trace_subsys_eventb();
return -EPERM;
}
static const struct file_operations mark_ops = {
.open = my_open,
.llseek = noop_llseek,
};
static int __init sample_init(void)
{
printk(KERN_ALERT "sample init\n");
pentry_sample = proc_create("tracepoint-sample", 0444, NULL,
&mark_ops);
if (!pentry_sample)
return -EPERM;
return 0;
}
static void __exit sample_exit(void)
{
printk(KERN_ALERT "sample exit\n");
remove_proc_entry("tracepoint-sample", NULL);
}
module_init(sample_init)
module_exit(sample_exit)
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("Tracepoint sample");
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