Lines Matching +full:sleep +full:- +full:map
1 .. SPDX-License-Identifier: GPL-2.0
15 2.2.2 Per-thread mode
16 2.2.3 Per-CPU mode
19 2.3.1 Producer-consumer model
55 -------------------
63 +---------------------------+
65 +---------------------------+
66 `-> Tail `-> Head
86 read-only mapping, which is to be addressed in the section
92 +---------+---------+ +---------------------------------------+
94 +---------+---------+ +---------------------------------------+
95 ` `----------------^ ^
96 `----------------------------------------------|
103 with option ``-m`` or ``--mmap-pages=``, the given size will be rounded up
105 allocates at once for all memory pages, it's deferred to map the pages
109 and the kernel uses this occasion to map the page into process VMA
114 -------------------------------------------
135 evsel::cpus::map[] = { 0 .. _SC_NPROCESSORS_ONLN-1 }
136 evsel::threads::map[] = { pid }
151 +----+ +-----------+ +----+
153 +----+--------------+-----------+----------+----+-------->
156 +-----------------------------------------------------+
158 +-----------------------------------------------------+
161 +-----+
163 -----+-----+--------------------------------------------->
166 +-----------------------------------------------------+
168 +-----------------------------------------------------+
171 +----+ +-------+
173 --------------------------+----+--------+-------+-------->
176 +-----------------------------------------------------+
178 +-----------------------------------------------------+
181 +--------------+
183 -----------+--------------+------------------------------>
186 +-----------------------------------------------------+
188 +-----------------------------------------------------+
195 2.2.2 Per-thread mode
198 By specifying option ``--per-thread`` in perf command, e.g.
202 perf record --per-thread test_program
204 The perf event doesn't map to any CPUs and is only bound to the
207 evsel::cpus::map[0] = { -1 }
208 evsel::threads::map[] = { pid }
221 +----+ +-----------+ +----+
223 +----+--------------+-----------+----------+----+-------->
226 | +-----+ |
228 --|--+-----+----------------------------------|---------->
231 | | +----+ +---+ |
233 --|-----|-----------------+----+--------+---+-|---------->
236 | | +--------------+ | |
238 --|-----|--+--------------+-|-----------------|---------->
241 +-----------------------------------------------------+
243 +-----------------------------------------------------+
248 Figure 4. Ring buffer for per-thread mode
250 When perf runs in per-thread mode, a ring buffer is allocated for the
256 2.2.3 Per-CPU mode
259 The option ``-C`` is used to collect samples on the list of CPUs, for
260 example the below perf command receives option ``-C 0,2``::
262 perf record -C 0,2 test_program
267 evsel::cpus::map[0] = { 0, 2 }
268 evsel::threads::map[] = { -1 }
275 options for per-thread mode and per-CPU mode, e.g. the options ``–C 0,2`` and
282 +----+ +-----------+ +----+
284 +----+--------------+-----------+----------+----+-------->
287 +-----------------------------------------------------+
289 +-----------------------------------------------------+
292 +-----+
294 -----+-----+--------------------------------------------->
297 +----+ +-------+
299 --------------------------+----+--------+-------+-------->
302 +-----------------------------------------------------+
304 +-----------------------------------------------------+
307 +--------------+
309 -----------+--------------+------------------------------>
314 Figure 5. Ring buffer for per-CPU mode
322 perf record -a test_program
324 Similar to the per-CPU mode, the perf event doesn't bind to any PID, and
327 evsel::cpus::map[] = { 0 .. _SC_NPROCESSORS_ONLN-1 }
328 evsel::threads::map[] = { -1 }
338 +----+ +-----------+ +----+
340 +----+--------------+-----------+----------+----+-------->
343 +-----------------------------------------------------+
345 +-----------------------------------------------------+
348 +-----+
350 -----+-----+--------------------------------------------->
353 +-----------------------------------------------------+
355 +-----------------------------------------------------+
358 +----+ +-------+
360 --------------------------+----+--------+-------+-------->
363 +-----------------------------------------------------+
365 +-----------------------------------------------------+
368 +--------------+
370 -----------+--------------+------------------------------>
373 +-----------------------------------------------------+
375 +-----------------------------------------------------+
383 --------------------
388 2.3.1 Producer-consumer model
394 data into the file for post analysis. It’s a typical producer-consumer
408 Polling / `--------------| Ring buffer
409 v v ;---------------------v
410 +----------------+ +---------+---------+ +-------------------+
412 +----------------+ +---------+---------+ +-------------------+
413 ^ ^ `------------------------^
415 +-----------------------------+
417 +-----------------------------+
445 Additionally, the tool can map buffers in either read-write mode or read-only
448 The ring buffer in the read-write mode is mapped with the property
455 Alternatively, in the read-only mode, only the kernel keeps to update
461 combinations to support buffer types: the non-overwrite buffer and the
464 .. list-table::
466 :header-rows: 1
468 * - Mapping mode
469 - Forward
470 - Backward
471 * - read-write
472 - Non-overwrite ring buffer
473 - Not used
474 * - read-only
475 - Not used
476 - Overwritable ring buffer
478 The non-overwrite ring buffer uses the read-write mapping with forward
480 and wrap around when overflow, which is used with the read-write mode in
487 read-only mode. It saves the data from the end of the ring buffer and
542 if (LOAD ->data_tail) { LOAD ->data_head
546 STORE ->data_head STORE ->data_tail
575 Some architectures support one-way permeable barrier with load-acquire
576 and store-release operations, these barriers are more relaxed with less
580 If an architecture doesn’t support load-acquire and store-release in its
593 examine how the AUX ring buffer co-works with the regular ring buffer,
598 ---------------------------------------------------------
619 During the initialisation phase, besides the mmap()-ed regular ring
622 non-zero file offset; ``rb_alloc_aux()`` in the kernel allocates pages
623 correspondingly, these pages will be deferred to map into VMA when
630 perf record -a -e cycles -e cs_etm/@tmc_etr0/ -- sleep 2
639 ring buffer and the AUX ring buffer per CPU-wise, which is the same as
642 in the system. For per-thread mode, the perf tool allocates only one
644 the per-CPU mode, the perf allocates two kinds of ring buffers for
645 selected CPUs specified by the option ``-C``.
655 +----+ +-----------+ +----+
657 +----+--------------+-----------+----------+----+-------->
660 +-----------------------------------------------------+
662 +-----------------------------------------------------+
665 +-----------------------------------------------------+
667 +-----------------------------------------------------+
670 +-----+
672 -----+-----+--------------------------------------------->
675 +-----------------------------------------------------+
677 +-----------------------------------------------------+
680 +-----------------------------------------------------+
682 +-----------------------------------------------------+
685 +----+ +-------+
687 --------------------------+----+--------+-------+-------->
690 +-----------------------------------------------------+
692 +-----------------------------------------------------+
695 +-----------------------------------------------------+
697 +-----------------------------------------------------+
700 +--------------+
702 -----------+--------------+------------------------------>
705 +-----------------------------------------------------+
707 +-----------------------------------------------------+
710 +-----------------------------------------------------+
712 +-----------------------------------------------------+
720 --------------
738 - It fills an event ``PERF_RECORD_AUX`` into the regular ring buffer, this
742 - Since the hardware trace driver has stored new trace data into the AUX
762 -----------------
769 perf record -e cs_etm/@tmc_etr0/u -S -a program &
772 kill -USR2 $PERFPID
773 sleep 1
778 - Before a snapshot is taken, the AUX ring buffer acts in free run mode.
782 - Once the perf tool receives the *USR2* signal, it triggers the callback
788 - Then perf tool takes a snapshot, ``record__read_auxtrace_snapshot()``
792 - After the snapshot is finished, ``auxtrace_record::snapshot_finish()``
804 As we know, the buffers' deployment can be per-thread mode, per-CPU
814 +------------------------+
815 | AUX Ring buffer 0 | <- aux_head
816 +------------------------+
818 +--------------------------------+
819 | AUX Ring buffer 1 | <- aux_head
820 +--------------------------------+
822 +--------------------------------------------+
823 | AUX Ring buffer 2 | <- aux_head
824 +--------------------------------------------+
826 +---------------------------------------+
827 | AUX Ring buffer 3 | <- aux_head
828 +---------------------------------------+