Commit 718c602d authored by Adrian Hunter's avatar Adrian Hunter Committed by Arnaldo Carvalho de Melo

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
......@@ -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
......
/*
* 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];
}
}
/*
* 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
......@@ -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,
......
......@@ -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);
......
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