Add parameter -f to rm in Makefile clean target
[lttng-ust.git] / include / lttng / ringbuffer-config.h
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1#ifndef _LTTNG_RING_BUFFER_CONFIG_H
2#define _LTTNG_RING_BUFFER_CONFIG_H
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3
4/*
e92f3e28 5 * lttng/ringbuffer-config.h
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6 *
7 * Copyright (C) 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
8 *
9 * Ring buffer configuration header. Note: after declaring the standard inline
10 * functions, clients should also include linux/ringbuffer/api.h.
11 *
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12 * Permission is hereby granted, free of charge, to any person obtaining a copy
13 * of this software and associated documentation files (the "Software"), to deal
14 * in the Software without restriction, including without limitation the rights
15 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
16 * copies of the Software, and to permit persons to whom the Software is
17 * furnished to do so, subject to the following conditions:
a60d70e6 18 *
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19 * The above copyright notice and this permission notice shall be included in
20 * all copies or substantial portions of the Software.
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21 *
22 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
23 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
25 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
26 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
27 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
28 * SOFTWARE.
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29 */
30
31#include <errno.h>
4318ae1b 32#include "lttng/ust-tracer.h"
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33#include <stdint.h>
34#include <stddef.h>
35#include <urcu/arch.h>
2e707419 36#include <string.h>
4318ae1b 37#include "lttng/align.h"
a8909ba5 38#include <lttng/ust-compiler.h>
a6352fd4 39
4cfec15c 40struct lttng_ust_lib_ring_buffer;
a6352fd4 41struct channel;
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42struct lttng_ust_lib_ring_buffer_config;
43struct lttng_ust_lib_ring_buffer_ctx;
5a821cd6 44struct lttng_ust_shm_handle;
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45
46/*
47 * Ring buffer client callbacks. Only used by slow path, never on fast path.
48 * For the fast path, record_header_size(), ring_buffer_clock_read() should be
49 * provided as inline functions too. These may simply return 0 if not used by
50 * the client.
51 */
4cfec15c 52struct lttng_ust_lib_ring_buffer_client_cb {
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53 /* Mandatory callbacks */
54
55 /* A static inline version is also required for fast path */
2fed87ae 56 uint64_t (*ring_buffer_clock_read) (struct channel *chan);
4cfec15c 57 size_t (*record_header_size) (const struct lttng_ust_lib_ring_buffer_config *config,
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58 struct channel *chan, size_t offset,
59 size_t *pre_header_padding,
4cfec15c 60 struct lttng_ust_lib_ring_buffer_ctx *ctx);
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61
62 /* Slow path only, at subbuffer switch */
63 size_t (*subbuffer_header_size) (void);
2fed87ae 64 void (*buffer_begin) (struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
1d498196 65 unsigned int subbuf_idx,
38fae1d3 66 struct lttng_ust_shm_handle *handle);
2fed87ae 67 void (*buffer_end) (struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc,
1d498196 68 unsigned int subbuf_idx, unsigned long data_size,
38fae1d3 69 struct lttng_ust_shm_handle *handle);
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70
71 /* Optional callbacks (can be set to NULL) */
72
73 /* Called at buffer creation/finalize */
4cfec15c 74 int (*buffer_create) (struct lttng_ust_lib_ring_buffer *buf, void *priv,
1d498196 75 int cpu, const char *name,
38fae1d3 76 struct lttng_ust_shm_handle *handle);
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77 /*
78 * Clients should guarantee that no new reader handle can be opened
79 * after finalize.
80 */
4cfec15c 81 void (*buffer_finalize) (struct lttng_ust_lib_ring_buffer *buf,
1d498196 82 void *priv, int cpu,
38fae1d3 83 struct lttng_ust_shm_handle *handle);
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84
85 /*
86 * Extract header length, payload length and timestamp from event
87 * record. Used by buffer iterators. Timestamp is only used by channel
88 * iterator.
89 */
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90 void (*record_get) (const struct lttng_ust_lib_ring_buffer_config *config,
91 struct channel *chan, struct lttng_ust_lib_ring_buffer *buf,
a6352fd4 92 size_t offset, size_t *header_len,
2fed87ae 93 size_t *payload_len, uint64_t *timestamp,
38fae1d3 94 struct lttng_ust_shm_handle *handle);
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95};
96
97/*
98 * Ring buffer instance configuration.
99 *
100 * Declare as "static const" within the client object to ensure the inline fast
101 * paths can be optimized.
102 *
103 * alloc/sync pairs:
104 *
105 * RING_BUFFER_ALLOC_PER_CPU and RING_BUFFER_SYNC_PER_CPU :
106 * Per-cpu buffers with per-cpu synchronization. Tracing must be performed
107 * with preemption disabled (lib_ring_buffer_get_cpu() and
108 * lib_ring_buffer_put_cpu()).
109 *
110 * RING_BUFFER_ALLOC_PER_CPU and RING_BUFFER_SYNC_GLOBAL :
111 * Per-cpu buffer with global synchronization. Tracing can be performed with
112 * preemption enabled, statistically stays on the local buffers.
113 *
114 * RING_BUFFER_ALLOC_GLOBAL and RING_BUFFER_SYNC_PER_CPU :
115 * Should only be used for buffers belonging to a single thread or protected
116 * by mutual exclusion by the client. Note that periodical sub-buffer switch
117 * should be disabled in this kind of configuration.
118 *
119 * RING_BUFFER_ALLOC_GLOBAL and RING_BUFFER_SYNC_GLOBAL :
120 * Global shared buffer with global synchronization.
121 *
122 * wakeup:
123 *
124 * RING_BUFFER_WAKEUP_BY_TIMER uses per-cpu deferrable timers to poll the
125 * buffers and wake up readers if data is ready. Mainly useful for tracers which
126 * don't want to call into the wakeup code on the tracing path. Use in
127 * combination with "read_timer_interval" channel_create() argument.
128 *
129 * RING_BUFFER_WAKEUP_BY_WRITER directly wakes up readers when a subbuffer is
130 * ready to read. Lower latencies before the reader is woken up. Mainly suitable
131 * for drivers.
132 *
133 * RING_BUFFER_WAKEUP_NONE does not perform any wakeup whatsoever. The client
134 * has the responsibility to perform wakeups.
135 */
2e707419 136#define LTTNG_UST_RING_BUFFER_CONFIG_PADDING 32
4cfec15c 137struct lttng_ust_lib_ring_buffer_config {
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138 enum {
139 RING_BUFFER_ALLOC_PER_CPU,
140 RING_BUFFER_ALLOC_GLOBAL,
141 } alloc;
142 enum {
143 RING_BUFFER_SYNC_PER_CPU, /* Wait-free */
144 RING_BUFFER_SYNC_GLOBAL, /* Lock-free */
145 } sync;
146 enum {
147 RING_BUFFER_OVERWRITE, /* Overwrite when buffer full */
148 RING_BUFFER_DISCARD, /* Discard when buffer full */
149 } mode;
150 enum {
151 RING_BUFFER_SPLICE,
152 RING_BUFFER_MMAP,
153 RING_BUFFER_READ, /* TODO */
154 RING_BUFFER_ITERATOR,
155 RING_BUFFER_NONE,
156 } output;
157 enum {
158 RING_BUFFER_PAGE,
159 RING_BUFFER_VMAP, /* TODO */
160 RING_BUFFER_STATIC, /* TODO */
161 } backend;
162 enum {
163 RING_BUFFER_NO_OOPS_CONSISTENCY,
164 RING_BUFFER_OOPS_CONSISTENCY,
165 } oops;
166 enum {
167 RING_BUFFER_IPI_BARRIER,
168 RING_BUFFER_NO_IPI_BARRIER,
169 } ipi;
170 enum {
171 RING_BUFFER_WAKEUP_BY_TIMER, /* wake up performed by timer */
172 RING_BUFFER_WAKEUP_BY_WRITER, /*
173 * writer wakes up reader,
174 * not lock-free
175 * (takes spinlock).
176 */
177 } wakeup;
178 /*
179 * tsc_bits: timestamp bits saved at each record.
180 * 0 and 64 disable the timestamp compression scheme.
181 */
182 unsigned int tsc_bits;
4cfec15c 183 struct lttng_ust_lib_ring_buffer_client_cb cb;
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184 /*
185 * client_type is used by the consumer process (which is in a
186 * different address space) to lookup the appropriate client
187 * callbacks and update the cb pointers.
188 */
189 int client_type;
2e707419 190 char padding[LTTNG_UST_RING_BUFFER_CONFIG_PADDING];
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191};
192
193/*
194 * ring buffer context
195 *
196 * Context passed to lib_ring_buffer_reserve(), lib_ring_buffer_commit(),
197 * lib_ring_buffer_try_discard_reserve(), lib_ring_buffer_align_ctx() and
198 * lib_ring_buffer_write().
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199 *
200 * IMPORTANT: this structure is part of the ABI between the probe and
201 * UST. Fields need to be only added at the end, never reordered, never
202 * removed.
a6352fd4 203 */
2e707419 204#define LTTNG_UST_RING_BUFFER_CTX_PADDING 24
4cfec15c 205struct lttng_ust_lib_ring_buffer_ctx {
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206 /* input received by lib_ring_buffer_reserve(), saved here. */
207 struct channel *chan; /* channel */
208 void *priv; /* client private data */
38fae1d3 209 struct lttng_ust_shm_handle *handle; /* shared-memory handle */
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210 size_t data_size; /* size of payload */
211 int largest_align; /*
212 * alignment of the largest element
213 * in the payload
214 */
215 int cpu; /* processor id */
216
217 /* output from lib_ring_buffer_reserve() */
4cfec15c 218 struct lttng_ust_lib_ring_buffer *buf; /*
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219 * buffer corresponding to processor id
220 * for this channel
221 */
222 size_t slot_size; /* size of the reserved slot */
223 unsigned long buf_offset; /* offset following the record header */
224 unsigned long pre_offset; /*
225 * Initial offset position _before_
226 * the record is written. Positioned
227 * prior to record header alignment
228 * padding.
229 */
2fed87ae 230 uint64_t tsc; /* time-stamp counter value */
a6352fd4 231 unsigned int rflags; /* reservation flags */
2e707419 232 char padding[LTTNG_UST_RING_BUFFER_CTX_PADDING];
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233};
234
235/**
236 * lib_ring_buffer_ctx_init - initialize ring buffer context
237 * @ctx: ring buffer context to initialize
238 * @chan: channel
239 * @priv: client private data
240 * @data_size: size of record data payload
241 * @largest_align: largest alignment within data payload types
242 * @cpu: processor id
243 */
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244static inline lttng_ust_notrace
245void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
246 struct channel *chan, void *priv,
247 size_t data_size, int largest_align,
248 int cpu, struct lttng_ust_shm_handle *handle);
a6352fd4 249static inline
4cfec15c 250void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
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251 struct channel *chan, void *priv,
252 size_t data_size, int largest_align,
38fae1d3 253 int cpu, struct lttng_ust_shm_handle *handle)
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254{
255 ctx->chan = chan;
256 ctx->priv = priv;
257 ctx->data_size = data_size;
258 ctx->largest_align = largest_align;
259 ctx->cpu = cpu;
260 ctx->rflags = 0;
1d498196 261 ctx->handle = handle;
2e707419 262 memset(ctx->padding, 0, LTTNG_UST_RING_BUFFER_CTX_PADDING);
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263}
264
265/*
266 * Reservation flags.
267 *
268 * RING_BUFFER_RFLAG_FULL_TSC
269 *
270 * This flag is passed to record_header_size() and to the primitive used to
271 * write the record header. It indicates that the full 64-bit time value is
272 * needed in the record header. If this flag is not set, the record header needs
273 * only to contain "tsc_bits" bit of time value.
274 *
275 * Reservation flags can be added by the client, starting from
276 * "(RING_BUFFER_FLAGS_END << 0)". It can be used to pass information from
277 * record_header_size() to lib_ring_buffer_write_record_header().
278 */
279#define RING_BUFFER_RFLAG_FULL_TSC (1U << 0)
280#define RING_BUFFER_RFLAG_END (1U << 1)
281
282/*
283 * We need to define RING_BUFFER_ALIGN_ATTR so it is known early at
284 * compile-time. We have to duplicate the "config->align" information and the
285 * definition here because config->align is used both in the slow and fast
286 * paths, but RING_BUFFER_ALIGN_ATTR is only available for the client code.
287 */
288#ifdef RING_BUFFER_ALIGN
289
290# define RING_BUFFER_ALIGN_ATTR /* Default arch alignment */
291
292/*
293 * Calculate the offset needed to align the type.
294 * size_of_type must be non-zero.
295 */
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296static inline lttng_ust_notrace
297unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type);
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298static inline
299unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
300{
301 return offset_align(align_drift, size_of_type);
302}
303
304#else
305
306# define RING_BUFFER_ALIGN_ATTR __attribute__((packed))
307
308/*
309 * Calculate the offset needed to align the type.
310 * size_of_type must be non-zero.
311 */
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312static inline lttng_ust_notrace
313unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type);
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314static inline
315unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
316{
317 return 0;
318}
319
320#endif
321
322/**
323 * lib_ring_buffer_align_ctx - Align context offset on "alignment"
324 * @ctx: ring buffer context.
325 */
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326static inline lttng_ust_notrace
327void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx,
328 size_t alignment);
a6352fd4 329static inline
4cfec15c 330void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx,
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331 size_t alignment)
332{
333 ctx->buf_offset += lib_ring_buffer_align(ctx->buf_offset,
334 alignment);
335}
336
337/*
338 * lib_ring_buffer_check_config() returns 0 on success.
339 * Used internally to check for valid configurations at channel creation.
340 */
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341static inline lttng_ust_notrace
342int lib_ring_buffer_check_config(const struct lttng_ust_lib_ring_buffer_config *config,
343 unsigned int switch_timer_interval,
344 unsigned int read_timer_interval);
a6352fd4 345static inline
4cfec15c 346int lib_ring_buffer_check_config(const struct lttng_ust_lib_ring_buffer_config *config,
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347 unsigned int switch_timer_interval,
348 unsigned int read_timer_interval)
349{
350 if (config->alloc == RING_BUFFER_ALLOC_GLOBAL
351 && config->sync == RING_BUFFER_SYNC_PER_CPU
352 && switch_timer_interval)
353 return -EINVAL;
354 return 0;
355}
356
e92f3e28 357#endif /* _LTTNG_RING_BUFFER_CONFIG_H */
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