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    Subject[PATCH v0 40/71] perf evlist: Add ability to mmap itrace buffers
    Date
    From: Adrian Hunter <adrian.hunter@intel.com>

    Instruction Tracing data is provided in a separate
    mmap made a special offset PERF_EVENT_ITRACE_OFFSET.
    Add the ability to mmap that offset.

    Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
    ---
    tools/perf/Makefile.perf | 2 +
    tools/perf/util/evlist.c | 57 +++++++++++++++++++++--
    tools/perf/util/evlist.h | 5 ++
    tools/perf/util/itrace.c | 104 +++++++++++++++++++++++++++++++++++++++++
    tools/perf/util/itrace.h | 118 +++++++++++++++++++++++++++++++++++++++++++++++
    5 files changed, 283 insertions(+), 3 deletions(-)
    create mode 100644 tools/perf/util/itrace.c
    create mode 100644 tools/perf/util/itrace.h

    diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
    index c1f9a54..6ef50f9 100644
    --- a/tools/perf/Makefile.perf
    +++ b/tools/perf/Makefile.perf
    @@ -293,6 +293,7 @@ LIB_H += util/perf_regs.h
    LIB_H += util/unwind.h
    LIB_H += util/vdso.h
    LIB_H += util/tsc.h
    +LIB_H += util/itrace.h
    LIB_H += ui/helpline.h
    LIB_H += ui/progress.h
    LIB_H += ui/util.h
    @@ -372,6 +373,7 @@ LIB_OBJS += $(OUTPUT)util/record.o
    LIB_OBJS += $(OUTPUT)util/srcline.o
    LIB_OBJS += $(OUTPUT)util/data.o
    LIB_OBJS += $(OUTPUT)util/tsc.o
    +LIB_OBJS += $(OUTPUT)util/itrace.o

    LIB_OBJS += $(OUTPUT)ui/setup.o
    LIB_OBJS += $(OUTPUT)ui/helpline.o
    diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
    index 490af37..c720c6c 100644
    --- a/tools/perf/util/evlist.c
    +++ b/tools/perf/util/evlist.c
    @@ -659,12 +659,39 @@ void perf_evlist__mmap_consume(struct perf_evlist *evlist, int idx)
    }
    }

    +int __weak itrace_mmap__mmap(struct itrace_mmap *mm __maybe_unused,
    + struct itrace_mmap_params *mp __maybe_unused,
    + int fd __maybe_unused)
    +{
    + return 0;
    +}
    +
    +void __weak itrace_mmap__munmap(struct itrace_mmap *mm __maybe_unused)
    +{
    +}
    +
    +void __weak itrace_mmap_params__init(
    + struct itrace_mmap_params *mp __maybe_unused,
    + unsigned int itrace_pages __maybe_unused,
    + bool itrace_overwrite __maybe_unused)
    +{
    +}
    +
    +void __weak itrace_mmap_params__set_idx(
    + struct itrace_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) {
    munmap(evlist->mmap[idx].base, evlist->mmap_len);
    evlist->mmap[idx].base = NULL;
    }
    + itrace_mmap__munmap(&evlist->mmap[idx].itrace_mmap);
    }

    void perf_evlist__munmap(struct perf_evlist *evlist)
    @@ -690,6 +717,7 @@ static int perf_evlist__alloc_mmap(struct perf_evlist *evlist)
    struct mmap_params {
    int prot;
    int mask;
    + struct itrace_mmap_params itrace_mp;
    };

    static int __perf_evlist__mmap(struct perf_evlist *evlist, int idx,
    @@ -706,6 +734,10 @@ static int __perf_evlist__mmap(struct perf_evlist *evlist, int idx,
    return -1;
    }

    + if (itrace_mmap__mmap(&evlist->mmap[idx].itrace_mmap,
    + &mp->itrace_mp, fd))
    + return -1;
    +
    perf_evlist__add_pollfd(evlist, fd);
    return 0;
    }
    @@ -756,6 +788,8 @@ static int perf_evlist__mmap_per_cpu(struct perf_evlist *evlist,
    for (cpu = 0; cpu < nr_cpus; cpu++) {
    int output = -1;

    + itrace_mmap_params__set_idx(&mp->itrace_mp, evlist, cpu, true);
    +
    for (thread = 0; thread < nr_threads; thread++) {
    if (perf_evlist__mmap_per_evsel(evlist, cpu, mp, cpu,
    thread, &output))
    @@ -781,6 +815,9 @@ static int perf_evlist__mmap_per_thread(struct perf_evlist *evlist,
    for (thread = 0; thread < nr_threads; thread++) {
    int output = -1;

    + itrace_mmap_params__set_idx(&mp->itrace_mp, evlist, thread,
    + false);
    +
    if (perf_evlist__mmap_per_evsel(evlist, thread, mp, 0, thread,
    &output))
    goto out_unmap;
    @@ -868,19 +905,25 @@ 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?
    + * @itrace_pages - itrace map length in pages
    + * @itrace_overwrite - overwrite older itrace 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 @itrace_overwrite is %false the user needs to signal data
    + * consumption using itrace_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 itrace_pages,
    + bool itrace_overwrite)
    {
    struct perf_evsel *evsel;
    const struct cpu_map *cpus = evlist->cpus;
    @@ -900,6 +943,8 @@ 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;

    + itrace_mmap_params__init(&mp.itrace_mp, itrace_pages, itrace_overwrite);
    +
    list_for_each_entry(evsel, &evlist->entries, node) {
    if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
    evsel->sample_id == NULL &&
    @@ -913,6 +958,12 @@ 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,
    diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
    index 6f3166e..7f56fdc 100644
    --- a/tools/perf/util/evlist.h
    +++ b/tools/perf/util/evlist.h
    @@ -7,6 +7,7 @@
    #include "event.h"
    #include "evsel.h"
    #include "util.h"
    +#include "itrace.h"
    #include <unistd.h>

    struct pollfd;
    @@ -21,6 +22,7 @@ struct perf_mmap {
    void *base;
    int mask;
    unsigned int prev;
    + struct itrace_mmap itrace_mmap;
    char event_copy[PERF_SAMPLE_MAX_SIZE];
    };

    @@ -111,6 +113,9 @@ 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 itrace_pages,
    + bool itrace_overwrite);
    int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages,
    bool overwrite);
    void perf_evlist__munmap(struct perf_evlist *evlist);
    diff --git a/tools/perf/util/itrace.c b/tools/perf/util/itrace.c
    new file mode 100644
    index 0000000..a889e63
    --- /dev/null
    +++ b/tools/perf/util/itrace.c
    @@ -0,0 +1,104 @@
    +/*
    + * itrace.c: Instruction Tracing support
    + * Copyright (c) 2013, 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.
    + *
    + * You should have received a copy of the GNU General Public License along with
    + * this program; if not, write to the Free Software Foundation, Inc.,
    + * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
    + *
    + */
    +
    +#include <sys/types.h>
    +#include <sys/mman.h>
    +#include <stdbool.h>
    +
    +#include <linux/kernel.h>
    +#include <linux/perf_event.h>
    +
    +#include "../perf.h"
    +#include "types.h"
    +#include "util.h"
    +#include "evlist.h"
    +#include "cpumap.h"
    +#include "thread_map.h"
    +#include "itrace.h"
    +
    +int itrace_mmap__mmap(struct itrace_mmap *mm, struct itrace_mmap_params *mp,
    + int fd)
    +{
    + off_t offs = PERF_EVENT_ITRACE_OFFSET;
    +
    +#if BITS_PER_LONG != 64 && !defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT)
    + pr_err("Cannot use Instruction Tracing mmaps\n");
    + return -1;
    +#endif
    +
    + mm->mask = mp->mask;
    + mm->len = mp->len;
    + mm->mmap_len = mp->mmap_len;
    + mm->prev = 0;
    + mm->idx = mp->idx;
    + mm->tid = mp->tid;
    + mm->cpu = mp->cpu;
    +
    + if (!mp->len) {
    + mm->base = NULL;
    + return 0;
    + }
    +
    + mm->base = mmap(NULL, mp->mmap_len, mp->prot, MAP_SHARED, fd, offs);
    + if (mm->base == MAP_FAILED) {
    + pr_debug2("failed to mmap itrace ring buffer\n");
    + mm->base = NULL;
    + return -1;
    + }
    +
    + return 0;
    +}
    +
    +void itrace_mmap__munmap(struct itrace_mmap *mm)
    +{
    + if (mm->base)
    + munmap(mm->base, mm->mmap_len);
    +}
    +
    +void itrace_mmap_params__init(struct itrace_mmap_params *mp,
    + unsigned int itrace_pages, bool itrace_overwrite)
    +{
    + if (itrace_pages) {
    + mp->len = itrace_pages * page_size;
    + mp->mmap_len = mp->len + page_size;
    + mp->mask = is_power_of_2(mp->len) ? mp->len - 1 : 0;
    + mp->prot = PROT_READ | (itrace_overwrite ? 0 : PROT_WRITE);
    + pr_debug2("itrace mmap length %zu\n", mp->mmap_len);
    + } else {
    + mp->len = 0;
    + }
    +}
    +
    +void itrace_mmap_params__set_idx(struct itrace_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];
    + }
    +}
    diff --git a/tools/perf/util/itrace.h b/tools/perf/util/itrace.h
    new file mode 100644
    index 0000000..4b17aca
    --- /dev/null
    +++ b/tools/perf/util/itrace.h
    @@ -0,0 +1,118 @@
    +/*
    + * itrace.h: Instruction Tracing support
    + * Copyright (c) 2013, 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.
    + *
    + * You should have received a copy of the GNU General Public License along with
    + * this program; if not, write to the Free Software Foundation, Inc.,
    + * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
    + *
    + */
    +
    +#ifndef __PERF_ITRACE_H
    +#define __PERF_ITRACE_H
    +
    +#include <sys/types.h>
    +#include <stdbool.h>
    +
    +#include <linux/perf_event.h>
    +
    +#include "../perf.h"
    +#include "types.h"
    +
    +struct perf_evlist;
    +
    +/**
    + * struct itrace_mmap - records an mmap at PERF_EVENT_ITRACE_OFFSET.
    + * @base: address of mapped area
    + * @mask: %0 if @len is not a power of two, otherwise (@len - %1)
    + * @len: size of mapped area excluding perf_event_mmap_page
    + * @mmap_len: size of mapped area including perf_event_mmap_page
    + * @prev: previous data_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 itrace_mmap {
    + void *base;
    + size_t mask;
    + size_t len;
    + size_t mmap_len;
    + u64 prev;
    + int idx;
    + pid_t tid;
    + int cpu;
    +};
    +
    +/**
    + * struct itrace_mmap_params - parameters to set up struct itrace_mmap.
    + * @mask: %0 if @len is not a power of two, otherwise (@len - %1)
    + * @len: size of mapped area excluding perf_event_mmap_page
    + * @mmap_len: size of mapped area including perf_event_mmap_page
    + * @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 itrace_mmap_params {
    + size_t mask;
    + size_t len;
    + size_t mmap_len;
    + int prot;
    + int idx;
    + pid_t tid;
    + int cpu;
    +};
    +
    +static inline u64 itrace_mmap__read_head(struct itrace_mmap *mm)
    +{
    + struct perf_event_mmap_page *pc = mm->base;
    +#if BITS_PER_LONG == 64 || !defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT)
    + u64 head = ACCESS_ONCE(pc->data_head);
    +#else
    + u64 head = __sync_val_compare_and_swap(&pc->data_head, 0, 0);
    +#endif
    +
    + /* Ensure all reads are done after we read the head */
    + rmb();
    + return head;
    +}
    +
    +static inline void itrace_mmap__write_tail(struct itrace_mmap *mm, u64 tail)
    +{
    + struct perf_event_mmap_page *pc = mm->base;
    +#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->data_tail = tail;
    +#else
    + do {
    + old_tail = __sync_val_compare_and_swap(&pc->data_tail, 0, 0);
    + } while (!__sync_bool_compare_and_swap(&pc->data_tail, old_tail, tail));
    +#endif
    +}
    +
    +int itrace_mmap__mmap(struct itrace_mmap *mm,
    + struct itrace_mmap_params *mp, int fd);
    +void itrace_mmap__munmap(struct itrace_mmap *mm);
    +void itrace_mmap_params__init(struct itrace_mmap_params *mp,
    + unsigned int itrace_pages, bool itrace_overwrite);
    +void itrace_mmap_params__set_idx(struct itrace_mmap_params *mp,
    + struct perf_evlist *evlist, int idx,
    + bool per_cpu);
    +
    +#endif
    --
    1.8.5.1


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