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authorThomas Gleixner <tglx@linutronix.de>2008-12-04 14:12:29 -0500
committerIngo Molnar <mingo@elte.hu>2008-12-08 09:47:03 -0500
commit0793a61d4df8daeac6492dbf8d2f3e5713caae5e (patch)
treecc9603eb8daffeb7ace521c42a6a44db164ac551 /include/linux/perf_counter.h
parentb5aa97e83bcc31a96374d18f5452d53909a16c90 (diff)
performance counters: core code
Implement the core kernel bits of Performance Counters subsystem. The Linux Performance Counter subsystem provides an abstraction of performance counter hardware capabilities. It provides per task and per CPU counters, and it provides event capabilities on top of those. Performance counters are accessed via special file descriptors. There's one file descriptor per virtual counter used. The special file descriptor is opened via the perf_counter_open() system call: int perf_counter_open(u32 hw_event_type, u32 hw_event_period, u32 record_type, pid_t pid, int cpu); The syscall returns the new fd. The fd can be used via the normal VFS system calls: read() can be used to read the counter, fcntl() can be used to set the blocking mode, etc. Multiple counters can be kept open at a time, and the counters can be poll()ed. See more details in Documentation/perf-counters.txt. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/linux/perf_counter.h')
-rw-r--r--include/linux/perf_counter.h171
1 files changed, 171 insertions, 0 deletions
diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
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1/*
2 * Performance counters:
3 *
4 * Copyright(C) 2008, Thomas Gleixner <tglx@linutronix.de>
5 * Copyright(C) 2008, Red Hat, Inc., Ingo Molnar
6 *
7 * Data type definitions, declarations, prototypes.
8 *
9 * Started by: Thomas Gleixner and Ingo Molnar
10 *
11 * For licencing details see kernel-base/COPYING
12 */
13#ifndef _LINUX_PERF_COUNTER_H
14#define _LINUX_PERF_COUNTER_H
15
16#include <asm/atomic.h>
17
18#include <linux/list.h>
19#include <linux/mutex.h>
20#include <linux/rculist.h>
21#include <linux/rcupdate.h>
22#include <linux/spinlock.h>
23
24struct task_struct;
25
26/*
27 * Generalized hardware event types, used by the hw_event_type parameter
28 * of the sys_perf_counter_open() syscall:
29 */
30enum hw_event_types {
31 PERF_COUNT_CYCLES,
32 PERF_COUNT_INSTRUCTIONS,
33 PERF_COUNT_CACHE_REFERENCES,
34 PERF_COUNT_CACHE_MISSES,
35 PERF_COUNT_BRANCH_INSTRUCTIONS,
36 PERF_COUNT_BRANCH_MISSES,
37 /*
38 * If this bit is set in the type, then trigger NMI sampling:
39 */
40 PERF_COUNT_NMI = (1 << 30),
41};
42
43/*
44 * IRQ-notification data record type:
45 */
46enum perf_record_type {
47 PERF_RECORD_SIMPLE,
48 PERF_RECORD_IRQ,
49 PERF_RECORD_GROUP,
50};
51
52/**
53 * struct hw_perf_counter - performance counter hardware details
54 */
55struct hw_perf_counter {
56 u64 config;
57 unsigned long config_base;
58 unsigned long counter_base;
59 int nmi;
60 unsigned int idx;
61 u64 prev_count;
62 s32 next_count;
63 u64 irq_period;
64};
65
66/*
67 * Hardcoded buffer length limit for now, for IRQ-fed events:
68 */
69#define PERF_DATA_BUFLEN 2048
70
71/**
72 * struct perf_data - performance counter IRQ data sampling ...
73 */
74struct perf_data {
75 int len;
76 int rd_idx;
77 int overrun;
78 u8 data[PERF_DATA_BUFLEN];
79};
80
81/**
82 * struct perf_counter - performance counter kernel representation:
83 */
84struct perf_counter {
85 struct list_head list;
86 int active;
87#if BITS_PER_LONG == 64
88 atomic64_t count;
89#else
90 atomic_t count32[2];
91#endif
92 u64 __irq_period;
93
94 struct hw_perf_counter hw;
95
96 struct perf_counter_context *ctx;
97 struct task_struct *task;
98
99 /*
100 * Protect attach/detach:
101 */
102 struct mutex mutex;
103
104 int oncpu;
105 int cpu;
106
107 s32 hw_event_type;
108 enum perf_record_type record_type;
109
110 /* read() / irq related data */
111 wait_queue_head_t waitq;
112 /* optional: for NMIs */
113 int wakeup_pending;
114 struct perf_data *irqdata;
115 struct perf_data *usrdata;
116 struct perf_data data[2];
117};
118
119/**
120 * struct perf_counter_context - counter context structure
121 *
122 * Used as a container for task counters and CPU counters as well:
123 */
124struct perf_counter_context {
125#ifdef CONFIG_PERF_COUNTERS
126 /*
127 * Protect the list of counters:
128 */
129 spinlock_t lock;
130 struct list_head counters;
131 int nr_counters;
132 int nr_active;
133 struct task_struct *task;
134#endif
135};
136
137/**
138 * struct perf_counter_cpu_context - per cpu counter context structure
139 */
140struct perf_cpu_context {
141 struct perf_counter_context ctx;
142 struct perf_counter_context *task_ctx;
143 int active_oncpu;
144 int max_pertask;
145};
146
147/*
148 * Set by architecture code:
149 */
150extern int perf_max_counters;
151
152#ifdef CONFIG_PERF_COUNTERS
153extern void perf_counter_task_sched_in(struct task_struct *task, int cpu);
154extern void perf_counter_task_sched_out(struct task_struct *task, int cpu);
155extern void perf_counter_task_tick(struct task_struct *task, int cpu);
156extern void perf_counter_init_task(struct task_struct *task);
157extern void perf_counter_notify(struct pt_regs *regs);
158extern void perf_counter_print_debug(void);
159#else
160static inline void
161perf_counter_task_sched_in(struct task_struct *task, int cpu) { }
162static inline void
163perf_counter_task_sched_out(struct task_struct *task, int cpu) { }
164static inline void
165perf_counter_task_tick(struct task_struct *task, int cpu) { }
166static inline void perf_counter_init_task(struct task_struct *task) { }
167static inline void perf_counter_notify(struct pt_regs *regs) { }
168static inline void perf_counter_print_debug(void) { }
169#endif
170
171#endif /* _LINUX_PERF_COUNTER_H */
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