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Commit 718c602d authored by Adrian Hunter's avatar Adrian Hunter Committed by Arnaldo Carvalho de Melo
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perf evlist: Add support for mmapping an AUX area buffer 



This patch supports the addition to the kernel of AUX area buffers that
can be mmapped separately from the perf-events buffer.

The AUX buffer can be configured to contain hardware-produced trace
information. The first implementation will support Intel BTS and Intel
PT.

One auxtrace buffer is mmapped per perf-events buffer.  If the requested
auxtrace buffer size is zero, which it will be until further support is
added, then no auxtrace mmapping is attempted.

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1428594864-29309-3-git-send-email-adrian.hunter@intel.com


[ Fixed conflict in evlist.h ]
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 4025ea40

tools/perf/util/Build

+1 −0
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ libperf-y += data.o 
libperf-$(CONFIG_X86) += tsc.o

libperf-y += cloexec.o

libperf-y += thread-stack.o

libperf-y += auxtrace.o



libperf-$(CONFIG_LIBELF) += symbol-elf.o

libperf-$(CONFIG_LIBELF) += probe-event.o

tools/perf/util/auxtrace.c

0 → 100644
+113 −0
Original line number Diff line number Diff line 
/*

 * auxtrace.c: AUX area trace support

 * Copyright (c) 2013-2015, Intel Corporation.

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms and conditions of the GNU General Public License,

 * version 2, as published by the Free Software Foundation.

 *

 * This program is distributed in the hope it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for

 * more details.

 *

 */



#include <sys/types.h>

#include <sys/mman.h>

#include <stdbool.h>



#include <linux/kernel.h>

#include <linux/perf_event.h>

#include <linux/types.h>

#include <linux/bitops.h>

#include <linux/log2.h>



#include "../perf.h"

#include "util.h"

#include "evlist.h"

#include "cpumap.h"

#include "thread_map.h"

#include "asm/bug.h"

#include "auxtrace.h"



int auxtrace_mmap__mmap(struct auxtrace_mmap *mm,

			struct auxtrace_mmap_params *mp,

			void *userpg, int fd)

{

	struct perf_event_mmap_page *pc = userpg;



#if BITS_PER_LONG != 64 && !defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT)

	pr_err("Cannot use AUX area tracing mmaps\n");

	return -1;

#endif



	WARN_ONCE(mm->base, "Uninitialized auxtrace_mmap\n");



	mm->userpg = userpg;

	mm->mask = mp->mask;

	mm->len = mp->len;

	mm->prev = 0;

	mm->idx = mp->idx;

	mm->tid = mp->tid;

	mm->cpu = mp->cpu;



	if (!mp->len) {

		mm->base = NULL;

		return 0;

	}



	pc->aux_offset = mp->offset;

	pc->aux_size = mp->len;



	mm->base = mmap(NULL, mp->len, mp->prot, MAP_SHARED, fd, mp->offset);

	if (mm->base == MAP_FAILED) {

		pr_debug2("failed to mmap AUX area\n");

		mm->base = NULL;

		return -1;

	}



	return 0;

}



void auxtrace_mmap__munmap(struct auxtrace_mmap *mm)

{

	if (mm->base) {

		munmap(mm->base, mm->len);

		mm->base = NULL;

	}

}



void auxtrace_mmap_params__init(struct auxtrace_mmap_params *mp,

				off_t auxtrace_offset,

				unsigned int auxtrace_pages,

				bool auxtrace_overwrite)

{

	if (auxtrace_pages) {

		mp->offset = auxtrace_offset;

		mp->len = auxtrace_pages * (size_t)page_size;

		mp->mask = is_power_of_2(mp->len) ? mp->len - 1 : 0;

		mp->prot = PROT_READ | (auxtrace_overwrite ? 0 : PROT_WRITE);

		pr_debug2("AUX area mmap length %zu\n", mp->len);

	} else {

		mp->len = 0;

	}

}



void auxtrace_mmap_params__set_idx(struct auxtrace_mmap_params *mp,

				   struct perf_evlist *evlist, int idx,

				   bool per_cpu)

{

	mp->idx = idx;



	if (per_cpu) {

		mp->cpu = evlist->cpus->map[idx];

		if (evlist->threads)

			mp->tid = evlist->threads->map[0];

		else

			mp->tid = -1;

	} else {

		mp->cpu = -1;

		mp->tid = evlist->threads->map[idx];

	}

}

tools/perf/util/auxtrace.h

0 → 100644
+117 −0
Original line number Diff line number Diff line 
/*

 * auxtrace.h: AUX area trace support

 * Copyright (c) 2013-2015, Intel Corporation.

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms and conditions of the GNU General Public License,

 * version 2, as published by the Free Software Foundation.

 *

 * This program is distributed in the hope it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for

 * more details.

 *

 */



#ifndef __PERF_AUXTRACE_H

#define __PERF_AUXTRACE_H



#include <sys/types.h>

#include <stdbool.h>



#include <linux/perf_event.h>

#include <linux/types.h>



#include "../perf.h"



struct perf_evlist;



/**

 * struct auxtrace_mmap - records an mmap of the auxtrace buffer.

 * @base: address of mapped area

 * @userpg: pointer to buffer's perf_event_mmap_page

 * @mask: %0 if @len is not a power of two, otherwise (@len - %1)

 * @len: size of mapped area

 * @prev: previous aux_head

 * @idx: index of this mmap

 * @tid: tid for a per-thread mmap (also set if there is only 1 tid on a per-cpu

 *       mmap) otherwise %0

 * @cpu: cpu number for a per-cpu mmap otherwise %-1

 */

struct auxtrace_mmap {

	void		*base;

	void		*userpg;

	size_t		mask;

	size_t		len;

	u64		prev;

	int		idx;

	pid_t		tid;

	int		cpu;

};



/**

 * struct auxtrace_mmap_params - parameters to set up struct auxtrace_mmap.

 * @mask: %0 if @len is not a power of two, otherwise (@len - %1)

 * @offset: file offset of mapped area

 * @len: size of mapped area

 * @prot: mmap memory protection

 * @idx: index of this mmap

 * @tid: tid for a per-thread mmap (also set if there is only 1 tid on a per-cpu

 *       mmap) otherwise %0

 * @cpu: cpu number for a per-cpu mmap otherwise %-1

 */

struct auxtrace_mmap_params {

	size_t		mask;

	off_t		offset;

	size_t		len;

	int		prot;

	int		idx;

	pid_t		tid;

	int		cpu;

};



static inline u64 auxtrace_mmap__read_head(struct auxtrace_mmap *mm)

{

	struct perf_event_mmap_page *pc = mm->userpg;

#if BITS_PER_LONG == 64 || !defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT)

	u64 head = ACCESS_ONCE(pc->aux_head);

#else

	u64 head = __sync_val_compare_and_swap(&pc->aux_head, 0, 0);

#endif



	/* Ensure all reads are done after we read the head */

	rmb();

	return head;

}



static inline void auxtrace_mmap__write_tail(struct auxtrace_mmap *mm, u64 tail)

{

	struct perf_event_mmap_page *pc = mm->userpg;

#if BITS_PER_LONG != 64 && defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT)

	u64 old_tail;

#endif



	/* Ensure all reads are done before we write the tail out */

	mb();

#if BITS_PER_LONG == 64 || !defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT)

	pc->aux_tail = tail;

#else

	do {

		old_tail = __sync_val_compare_and_swap(&pc->aux_tail, 0, 0);

	} while (!__sync_bool_compare_and_swap(&pc->aux_tail, old_tail, tail));

#endif

}



int auxtrace_mmap__mmap(struct auxtrace_mmap *mm,

			struct auxtrace_mmap_params *mp,

			void *userpg, int fd);

void auxtrace_mmap__munmap(struct auxtrace_mmap *mm);

void auxtrace_mmap_params__init(struct auxtrace_mmap_params *mp,

				off_t auxtrace_offset,

				unsigned int auxtrace_pages,

				bool auxtrace_overwrite);

void auxtrace_mmap_params__set_idx(struct auxtrace_mmap_params *mp,

				   struct perf_evlist *evlist, int idx,

				   bool per_cpu);



#endif

tools/perf/util/evlist.c

+58 −3
Original line number Diff line number Diff line
@@ -725,6 +725,34 @@ void perf_evlist__mmap_consume(struct perf_evlist *evlist, int idx) 
		perf_evlist__mmap_put(evlist, idx);

}



int __weak auxtrace_mmap__mmap(struct auxtrace_mmap *mm __maybe_unused,

			       struct auxtrace_mmap_params *mp __maybe_unused,

			       void *userpg __maybe_unused,

			       int fd __maybe_unused)

{

	return 0;

}



void __weak auxtrace_mmap__munmap(struct auxtrace_mmap *mm __maybe_unused)

{

}



void __weak auxtrace_mmap_params__init(

			struct auxtrace_mmap_params *mp __maybe_unused,

			off_t auxtrace_offset __maybe_unused,

			unsigned int auxtrace_pages __maybe_unused,

			bool auxtrace_overwrite __maybe_unused)

{

}



void __weak auxtrace_mmap_params__set_idx(

			struct auxtrace_mmap_params *mp __maybe_unused,

			struct perf_evlist *evlist __maybe_unused,

			int idx __maybe_unused,

			bool per_cpu __maybe_unused)

{

}



static void __perf_evlist__munmap(struct perf_evlist *evlist, int idx)

{

	if (evlist->mmap[idx].base != NULL) {
@@ -732,6 +760,7 @@ static void __perf_evlist__munmap(struct perf_evlist *evlist, int idx) 
		evlist->mmap[idx].base = NULL;

		evlist->mmap[idx].refcnt = 0;

	}

	auxtrace_mmap__munmap(&evlist->mmap[idx].auxtrace_mmap);

}



void perf_evlist__munmap(struct perf_evlist *evlist)
@@ -759,6 +788,7 @@ static int perf_evlist__alloc_mmap(struct perf_evlist *evlist) 
struct mmap_params {

	int prot;

	int mask;

	struct auxtrace_mmap_params auxtrace_mp;

};



static int __perf_evlist__mmap(struct perf_evlist *evlist, int idx,
@@ -789,6 +819,10 @@ static int __perf_evlist__mmap(struct perf_evlist *evlist, int idx, 
		return -1;

	}



	if (auxtrace_mmap__mmap(&evlist->mmap[idx].auxtrace_mmap,

				&mp->auxtrace_mp, evlist->mmap[idx].base, fd))

		return -1;



	return 0;

}
@@ -853,6 +887,9 @@ static int perf_evlist__mmap_per_cpu(struct perf_evlist *evlist, 
	for (cpu = 0; cpu < nr_cpus; cpu++) {

		int output = -1;



		auxtrace_mmap_params__set_idx(&mp->auxtrace_mp, evlist, cpu,

					      true);



		for (thread = 0; thread < nr_threads; thread++) {

			if (perf_evlist__mmap_per_evsel(evlist, cpu, mp, cpu,

							thread, &output))
@@ -878,6 +915,9 @@ static int perf_evlist__mmap_per_thread(struct perf_evlist *evlist, 
	for (thread = 0; thread < nr_threads; thread++) {

		int output = -1;



		auxtrace_mmap_params__set_idx(&mp->auxtrace_mp, evlist, thread,

					      false);



		if (perf_evlist__mmap_per_evsel(evlist, thread, mp, 0, thread,

						&output))

			goto out_unmap;
@@ -981,19 +1021,25 @@ int perf_evlist__parse_mmap_pages(const struct option *opt, const char *str, 
}



/**

 * perf_evlist__mmap - Create mmaps to receive events.

 * perf_evlist__mmap_ex - Create mmaps to receive events.

 * @evlist: list of events

 * @pages: map length in pages

 * @overwrite: overwrite older events?

 * @auxtrace_pages - auxtrace map length in pages

 * @auxtrace_overwrite - overwrite older auxtrace data?

 *

 * If @overwrite is %false the user needs to signal event consumption using

 * perf_mmap__write_tail().  Using perf_evlist__mmap_read() does this

 * automatically.

 *

 * Similarly, if @auxtrace_overwrite is %false the user needs to signal data

 * consumption using auxtrace_mmap__write_tail().

 *

 * Return: %0 on success, negative error code otherwise.

 */

int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages,

		      bool overwrite)

int perf_evlist__mmap_ex(struct perf_evlist *evlist, unsigned int pages,

			 bool overwrite, unsigned int auxtrace_pages,

			 bool auxtrace_overwrite)

{

	struct perf_evsel *evsel;

	const struct cpu_map *cpus = evlist->cpus;
@@ -1013,6 +1059,9 @@ int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages, 
	pr_debug("mmap size %zuB\n", evlist->mmap_len);

	mp.mask = evlist->mmap_len - page_size - 1;



	auxtrace_mmap_params__init(&mp.auxtrace_mp, evlist->mmap_len,

				   auxtrace_pages, auxtrace_overwrite);



	evlist__for_each(evlist, evsel) {

		if ((evsel->attr.read_format & PERF_FORMAT_ID) &&

		    evsel->sample_id == NULL &&
@@ -1026,6 +1075,12 @@ int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages, 
	return perf_evlist__mmap_per_cpu(evlist, &mp);

}



int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages,

		      bool overwrite)

{

	return perf_evlist__mmap_ex(evlist, pages, overwrite, 0, false);

}



int perf_evlist__create_maps(struct perf_evlist *evlist, struct target *target)

{

	evlist->threads = thread_map__new_str(target->pid, target->tid,

tools/perf/util/evlist.h

+5 −0
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
#include "event.h"

#include "evsel.h"

#include "util.h"

#include "auxtrace.h"

#include <unistd.h>



struct pollfd;
@@ -28,6 +29,7 @@ struct perf_mmap { 
	int		 mask;

	int		 refcnt;

	u64		 prev;

	struct auxtrace_mmap auxtrace_mmap;

	char		 event_copy[PERF_SAMPLE_MAX_SIZE] __attribute__((aligned(8)));

};
@@ -126,6 +128,9 @@ int perf_evlist__parse_mmap_pages(const struct option *opt, 
				  const char *str,

				  int unset);



int perf_evlist__mmap_ex(struct perf_evlist *evlist, unsigned int pages,

			 bool overwrite, unsigned int auxtrace_pages,

			 bool auxtrace_overwrite);

int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages,

		      bool overwrite);

void perf_evlist__munmap(struct perf_evlist *evlist);