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authorSteven Rostedt <srostedt@redhat.com>2008-05-12 15:20:42 -0400
committerThomas Gleixner <tglx@linutronix.de>2008-05-23 14:32:06 -0400
commitbc0c38d139ec7fcd5c030aea16b008f3732e42ac (patch)
treeadaaf5e2ca49bbd7025bc357f87df9cb47641022 /kernel/trace/trace.h
parent16444a8a40d4c7b4f6de34af0cae1f76a4f6c901 (diff)
ftrace: latency tracer infrastructure
This patch adds the latency tracer infrastructure. This patch does not add anything that will select and turn it on, but will be used by later patches. If it were to be compiled, it would add the following files to the debugfs: The root tracing directory: /debugfs/tracing/ This patch also adds the following files: available_tracers list of available tracers. Currently no tracers are available. Looking into this file only shows "none" which is used to unregister all tracers. current_tracer The trace that is currently active. Empty on start up. To switch to a tracer simply echo one of the tracers that are listed in available_tracers: example: (used with later patches) echo function > /debugfs/tracing/current_tracer To disable the tracer: echo disable > /debugfs/tracing/current_tracer tracing_enabled echoing "1" into this file starts the ftrace function tracing (if sysctl kernel.ftrace_enabled=1) echoing "0" turns it off. latency_trace This file is readonly and holds the result of the trace. trace This file outputs a easier to read version of the trace. iter_ctrl Controls the way the output of traces look. So far there's two controls: echoing in "symonly" will only show the kallsyms variables without the addresses (if kallsyms was configured) echoing in "verbose" will change the output to show a lot more data, but not very easy to understand by humans. echoing in "nosymonly" turns off symonly. echoing in "noverbose" turns off verbose. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/trace/trace.h')
-rw-r--r--kernel/trace/trace.h184
1 files changed, 184 insertions, 0 deletions
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
new file mode 100644
index 000000000000..3173a93561d4
--- /dev/null
+++ b/kernel/trace/trace.h
@@ -0,0 +1,184 @@
1#ifndef _LINUX_KERNEL_TRACE_H
2#define _LINUX_KERNEL_TRACE_H
3
4#include <linux/fs.h>
5#include <asm/atomic.h>
6#include <linux/sched.h>
7#include <linux/clocksource.h>
8
9/*
10 * Function trace entry - function address and parent function addres:
11 */
12struct ftrace_entry {
13 unsigned long ip;
14 unsigned long parent_ip;
15};
16
17/*
18 * Context switch trace entry - which task (and prio) we switched from/to:
19 */
20struct ctx_switch_entry {
21 unsigned int prev_pid;
22 unsigned char prev_prio;
23 unsigned char prev_state;
24 unsigned int next_pid;
25 unsigned char next_prio;
26};
27
28/*
29 * The trace entry - the most basic unit of tracing. This is what
30 * is printed in the end as a single line in the trace output, such as:
31 *
32 * bash-15816 [01] 235.197585: idle_cpu <- irq_enter
33 */
34struct trace_entry {
35 char type;
36 char cpu;
37 char flags;
38 char preempt_count;
39 int pid;
40 cycle_t t;
41 unsigned long idx;
42 union {
43 struct ftrace_entry fn;
44 struct ctx_switch_entry ctx;
45 };
46};
47
48#define TRACE_ENTRY_SIZE sizeof(struct trace_entry)
49
50/*
51 * The CPU trace array - it consists of thousands of trace entries
52 * plus some other descriptor data: (for example which task started
53 * the trace, etc.)
54 */
55struct trace_array_cpu {
56 void *trace;
57 unsigned long trace_idx;
58 atomic_t disabled;
59 atomic_t underrun;
60 unsigned long saved_latency;
61 unsigned long critical_start;
62 unsigned long critical_end;
63 unsigned long critical_sequence;
64 unsigned long nice;
65 unsigned long policy;
66 unsigned long rt_priority;
67 cycle_t preempt_timestamp;
68 pid_t pid;
69 uid_t uid;
70 char comm[TASK_COMM_LEN];
71};
72
73struct trace_iterator;
74
75/*
76 * The trace array - an array of per-CPU trace arrays. This is the
77 * highest level data structure that individual tracers deal with.
78 * They have on/off state as well:
79 */
80struct trace_array {
81 unsigned long entries;
82 long ctrl;
83 int cpu;
84 cycle_t time_start;
85 struct trace_array_cpu *data[NR_CPUS];
86};
87
88/*
89 * A specific tracer, represented by methods that operate on a trace array:
90 */
91struct tracer {
92 const char *name;
93 void (*init)(struct trace_array *tr);
94 void (*reset)(struct trace_array *tr);
95 void (*open)(struct trace_iterator *iter);
96 void (*close)(struct trace_iterator *iter);
97 void (*start)(struct trace_iterator *iter);
98 void (*stop)(struct trace_iterator *iter);
99 void (*ctrl_update)(struct trace_array *tr);
100 struct tracer *next;
101 int print_max;
102};
103
104/*
105 * Trace iterator - used by printout routines who present trace
106 * results to users and which routines might sleep, etc:
107 */
108struct trace_iterator {
109 struct trace_array *tr;
110 struct tracer *trace;
111 struct trace_entry *ent;
112 unsigned long iter_flags;
113 loff_t pos;
114 unsigned long next_idx[NR_CPUS];
115 int cpu;
116 int idx;
117};
118
119void notrace tracing_reset(struct trace_array_cpu *data);
120int tracing_open_generic(struct inode *inode, struct file *filp);
121struct dentry *tracing_init_dentry(void);
122void ftrace(struct trace_array *tr,
123 struct trace_array_cpu *data,
124 unsigned long ip,
125 unsigned long parent_ip,
126 unsigned long flags);
127void tracing_sched_switch_trace(struct trace_array *tr,
128 struct trace_array_cpu *data,
129 struct task_struct *prev,
130 struct task_struct *next,
131 unsigned long flags);
132void tracing_record_cmdline(struct task_struct *tsk);
133
134void tracing_start_function_trace(void);
135void tracing_stop_function_trace(void);
136int register_tracer(struct tracer *type);
137void unregister_tracer(struct tracer *type);
138
139extern unsigned long nsecs_to_usecs(unsigned long nsecs);
140
141extern unsigned long tracing_max_latency;
142extern unsigned long tracing_thresh;
143
144void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu);
145void update_max_tr_single(struct trace_array *tr,
146 struct task_struct *tsk, int cpu);
147
148static inline notrace cycle_t now(int cpu)
149{
150 return cpu_clock(cpu);
151}
152
153#ifdef CONFIG_SCHED_TRACER
154extern void notrace
155wakeup_sched_switch(struct task_struct *prev, struct task_struct *next);
156#else
157static inline void
158wakeup_sched_switch(struct task_struct *prev, struct task_struct *next)
159{
160}
161#endif
162
163#ifdef CONFIG_CONTEXT_SWITCH_TRACER
164typedef void
165(*tracer_switch_func_t)(void *private,
166 struct task_struct *prev,
167 struct task_struct *next);
168
169struct tracer_switch_ops {
170 tracer_switch_func_t func;
171 void *private;
172 struct tracer_switch_ops *next;
173};
174
175extern int register_tracer_switch(struct tracer_switch_ops *ops);
176extern int unregister_tracer_switch(struct tracer_switch_ops *ops);
177
178#endif /* CONFIG_CONTEXT_SWITCH_TRACER */
179
180#ifdef CONFIG_DYNAMIC_FTRACE
181extern unsigned long ftrace_update_tot_cnt;
182#endif
183
184#endif /* _LINUX_KERNEL_TRACE_H */
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