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    Subject[PATCH 6/7] perf, x86: Example code for AMD IBS
    Date
    This patch includes an example to use IBS via perf_event.

    usage: ibs [-h]
    ibs ibs_fetch | ibs_op [-s] [-C CPU] [-m BUFFERPAGES] <command>

    <command>
    Command to execute.

    -e CONFIG
    64 bit configuration value, refers to msrs
    IbsFetchCtl (0xC0011030) or IbsOpCtl (0xC0011033).
    The default sample period is set to 100000.

    -c COUNT
    Event period to sample (default: 100000).

    -h
    Print help.

    -s
    system wide profiling (set per default)

    -C CPU
    profile on CPU (not yet implemented)

    -m BUFFERPAGES
    Per-cpu buffer pages to allocate.

    Signed-off-by: Robert Richter <robert.richter@amd.com>
    ---
    tools/perf/Documentation/examples/Makefile | 44 +++
    tools/perf/Documentation/examples/ibs.c | 436 ++++++++++++++++++++++++++++
    2 files changed, 480 insertions(+), 0 deletions(-)
    create mode 100644 tools/perf/Documentation/examples/Makefile
    create mode 100644 tools/perf/Documentation/examples/ibs.c

    diff --git a/tools/perf/Documentation/examples/Makefile b/tools/perf/Documentation/examples/Makefile
    new file mode 100644
    index 0000000..cfc9647
    --- /dev/null
    +++ b/tools/perf/Documentation/examples/Makefile
    @@ -0,0 +1,44 @@
    +all: ibs
    +
    +CFLAGS += -I../..
    +CFLAGS += -I../../util/include
    +CFLAGS += -DNO_NEWT_SUPPORT
    +
    +LIB_FILE=../../libperf.a
    +
    +INSTALL = install
    +
    +ifeq ("$(origin O)", "command line")
    + OUTPUT := $(O)/
    +endif
    +
    +ifneq ($(OUTPUT),)
    +# check that the output directory actually exists
    +OUTDIR := $(shell cd $(OUTPUT) && /bin/pwd)
    +$(if $(OUTDIR),, $(error output directory "$(OUTPUT)" does not exist))
    +endif
    +
    +ifndef DESTDIR
    +prefix = $(HOME)
    +endif
    +bindir_relative = bin
    +bindir = $(prefix)/$(bindir_relative)
    +
    +DESTDIR_SQ = $(subst ','\'',$(DESTDIR))
    +bindir_SQ = $(subst ','\'',$(bindir))
    +
    +../../libperf.a:
    + $(MAKE) CFLAGS="-DNO_NEWT_SUPPORT" -C ../.. libperf.a
    +
    +$(OUTPUT)ibs: ibs.c $(LIB_FILE)
    + $(CC) $(CFLAGS) $^ -o $@
    +
    +clean:
    + $(MAKE) -C ../.. clean
    + $(RM) ibs
    +
    +install: all
    + $(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(bindir_SQ)'
    + $(INSTALL) $(OUTPUT)ibs '$(DESTDIR_SQ)$(bindir_SQ)'
    +
    +.PHONY: all clean install
    diff --git a/tools/perf/Documentation/examples/ibs.c b/tools/perf/Documentation/examples/ibs.c
    new file mode 100644
    index 0000000..3d4e334
    --- /dev/null
    +++ b/tools/perf/Documentation/examples/ibs.c
    @@ -0,0 +1,436 @@
    +/*
    + * IBS sampling example
    + *
    + * Copyright (C) 2011 Advanced Micro Devices, Inc., Robert Richter
    + *
    + * Sample code that attaches an event to a specified PMU.
    + *
    + * Compiling:
    + *
    + * $ cd linux # Linux kernel source dir
    + * $ make -C tools/perf/Documentation/examples ibs
    + *
    + * Running:
    + *
    + * $ ./ibs ibs_fetch -s -m 256 <command>
    + *
    + */
    +
    +#include <errno.h>
    +#include <fcntl.h>
    +#include <string.h>
    +#include <stdio.h>
    +#include <poll.h>
    +#include <stdlib.h>
    +#include <sys/ptrace.h>
    +#include <signal.h>
    +#include <setjmp.h>
    +#include <inttypes.h>
    +
    +#include "util/evsel.h"
    +#include "util/evlist.h"
    +#include "util/cpumap.h"
    +#include "util/thread_map.h"
    +
    +struct perf_config {
    + uint64_t config;
    + uint64_t sample_period;
    + char *sysfs;
    + int pid;
    + int cpu;
    + int mmap_pages;
    + char **argv;
    +};
    +
    +static uint64_t collected_samples, lost_samples, sum_period;
    +
    +static void usage(void)
    +{
    + printf(
    +"usage: ibs [-h]\n"
    +" ibs ibs_fetch | ibs_op [-s] [-C CPU] [-m BUFFERPAGES] <command>\n"
    +"\n"
    +" <command>\n"
    +" Command to execute.\n"
    +"\n"
    +" -e CONFIG\n"
    +" 64 bit configuration value, refers to msrs\n"
    +" IbsFetchCtl (0xC0011030) or IbsOpCtl (0xC0011033).\n"
    +" The default sample period is set to 100000.\n"
    +"\n"
    +" -c COUNT\n"
    +" Event period to sample (default: 100000).\n"
    +"\n"
    +" -h\n"
    +" Print help.\n"
    +"\n"
    +" -s\n"
    +" system wide profiling (set per default)\n"
    +"\n"
    +" -C CPU\n"
    +" profile on CPU (not yet implemented)\n"
    +"\n"
    +" -m BUFFERPAGES\n"
    +" Per-cpu buffer pages to allocate.\n"
    +);
    + exit(0);
    +}
    +
    +#define IBS_FETCH_DEFAULT ((1ULL<<57)|(100000ULL>>4))
    +#define IBS_OP_DEFAULT ((0ULL<<19)|(100000ULL>>4))
    +
    +#define IBS_MAX_CNT 0x0000FFFFULL
    +
    +#define IBS_FETCH_SYSFS "/sys/bus/event_source/devices/ibs_fetch/type"
    +#define IBS_OP_SYSFS "/sys/bus/event_source/devices/ibs_op/type"
    +
    +static int ibs_config(struct perf_config *config, int argc, char **argv)
    +{
    + int c;
    +
    + memset(config, 0, sizeof(*config));
    + config->pid = -1; /* support for system wide profiling only */
    + config->cpu = -1;
    + config->mmap_pages = 1; /* need buffer for ibs */
    +
    + c = getopt(argc, argv,"+h");
    + if (c != -1 || !argv[optind]) {
    + usage();
    + exit(0);
    + }
    +
    + if (!strcmp(argv[optind], "ibs_fetch")) {
    + config->sysfs = IBS_FETCH_SYSFS;
    + config->config = IBS_FETCH_DEFAULT;
    + } else if (!strcmp(argv[optind], "ibs_op")) {
    + config->sysfs = IBS_OP_SYSFS;
    + config->config = IBS_OP_DEFAULT;
    + } else {
    + errx(1, "specify ibs_fetch or ibs_op\n");
    + }
    +
    + optind++;
    +
    + while (1) {
    + c = getopt(argc, argv,"+he:c:sC:m:v");
    + if (c == -1)
    + break;
    + switch (c) {
    + case 'h':
    + usage();
    + exit(0);
    + case 'e':
    + /* event configuration */
    + config->config = atoll(optarg);
    + break;
    + case 'c':
    + /* sample period */
    + config->sample_period = atoll(optarg);
    + config->config &= ~IBS_MAX_CNT;
    + if (!config->sample_period)
    + errx(1, "invalid sample period");
    + break;
    + case 's':
    + /* system wide profiling */
    + if (config->pid)
    + break;
    + config->pid = -1;
    + config->cpu = -1;
    + break;
    + case 'C':
    + /* profile cpu */
    + config->pid = -1;
    + config->cpu = atoi(optarg);
    + break;
    + case 'm':
    + config->mmap_pages = atoi(optarg);
    + break;
    + default:
    + errx(1, "unknown option");
    + }
    + }
    +
    + if (!argv[optind])
    + errx(1, "you must specify a command to execute\n");
    +
    + config->argv = argv + optind;
    +
    + if (config->mmap_pages > 1 && ((config->mmap_pages) & 0x1))
    + errx(1, "number of pages must be power of 2\n");
    +
    + return 0;
    +}
    +
    +#define BUFSIZ_ATOI 32
    +
    +static int get_pmu_type(char *sysfs)
    +{ int pmu, ret = 0;
    + char buf[BUFSIZ_ATOI];
    + size_t size;
    +
    + pmu = open(sysfs, O_RDONLY);
    + if (pmu == -1)
    + return -errno;
    + size = read(pmu, buf, BUFSIZ - 1);
    + if (size < 0)
    + ret = -errno;
    + close(pmu);
    +
    + if (ret)
    + return ret;
    +
    + buf[size] = '0';
    +
    + return atoi(buf);
    +}
    +
    +static volatile int done = 0;
    +
    +static void cld_handler(int n)
    +{
    + done = 1;
    +}
    +
    +static int child(char **arg)
    +{
    + ptrace(PTRACE_TRACEME, 0, NULL, NULL);
    + execvp(arg[0], arg);
    + return -1;
    +}
    +
    +static void print_ibs_fetch(int cpu, uint64_t *ibs)
    +{
    + printf("IBS_fetch sample on cpu%d\tIBS0: 0x%016"PRIx64" IBS1: 0x%016"PRIx64" IBS2:0x%016"PRIx64"\n",
    + cpu, ibs[0], ibs[1], ibs[2]);
    +}
    +
    +static void print_ibs_op(int cpu, uint64_t *ibs)
    +{
    + printf("IBS_OP sample on cpu%d\t"
    + "\t IBS0: 0x%016"PRIx64" IBS1: 0x%016"PRIx64" IBS2: 0x%016"PRIx64"\n"
    + "\tIBS3: 0x%016"PRIx64" IBS4: 0x%016"PRIx64" IBS5: 0x%016"PRIx64" IBS6: 0x%016"PRIx64"\n",
    + cpu, ibs[0], ibs[1], ibs[2], ibs[3], ibs[4], ibs[5], ibs[6]);
    +}
    +
    +#define MSR_AMD64_IBSFETCH_SIZE 3
    +#define MSR_AMD64_IBSOP_SIZE 7
    +
    +static int print_ibs(struct perf_sample *sample)
    +{
    + switch (sample->raw_size >> 3) {
    + case MSR_AMD64_IBSFETCH_SIZE:
    + print_ibs_fetch(sample->cpu, sample->raw_data);
    + return 0;
    + case MSR_AMD64_IBSOP_SIZE:
    + print_ibs_op(sample->cpu, sample->raw_data);
    + return 0;
    + default:
    + printf("invalid: raw_size = %d, p = %p\n",
    + sample->raw_size, (u64*)sample->raw_data);
    + return -EINVAL;
    + }
    +}
    +
    +static void print_event(union perf_event *event)
    +{
    + int idx, size = event->sample.header.size;
    + u64 *val = event->sample.array;
    +
    + printf("unrecognized event, type = %d, size = %d, header = 0x%016"PRIx64":\n",
    + event->sample.header.type, size, *(u64*)&event->sample.header);
    +
    + for (idx = 1; size > 0; idx++, size -= 8) {
    + printf(" 0x%016"PRIx64, *val++);
    + if (!(idx % 8))
    + printf("\n");
    + }
    + printf("\n");
    +}
    +
    +static int ibs_run(struct perf_config *config)
    +{
    + struct perf_event_attr attr;
    + struct perf_sample sample;
    + struct perf_evsel *evsel = NULL;
    + struct perf_evlist *evlist = NULL;
    + struct cpu_map *cpus = NULL;
    + struct thread_map *threads = NULL;
    + struct perf_evsel *pos, *n;
    + union perf_event *event;
    + pid_t pid = config->pid;
    + char cpu_list[8];
    + int type, idx, status, ready = 0;
    + int ret = -ENOMEM;
    + static uint64_t ovfl_count; /* static to avoid setjmp issue */
    +
    + type = get_pmu_type(config->sysfs);
    + if (type < 0) {
    + fprintf(stderr, "Failed to get pmu type: %d\n", type);
    + return type;
    + }
    +
    + memset(&attr, 0, sizeof(attr));
    + attr.type = type;
    + attr.sample_type = PERF_SAMPLE_CPU | PERF_SAMPLE_RAW;
    + attr.sample_period = config->sample_period;
    + attr.config = config->config;
    +
    + evsel = perf_evsel__new(&attr, 0);
    +
    + if (config->cpu == -1) {
    + cpus = cpu_map__new(NULL);
    + } else {
    + snprintf(cpu_list, sizeof(cpu_list), "%d", config->cpu);
    + cpus = cpu_map__new(cpu_list);
    + }
    +
    + threads = thread_map__new(pid, pid);
    +
    + evlist = perf_evlist__new(cpus, threads);
    +
    + if (!evsel || !evlist || !cpus || !threads)
    + goto out;
    +
    + ret = perf_evsel__alloc_counts(evsel, cpus->nr);
    + if (ret < 0)
    + goto out;
    +
    + perf_evlist__add(evlist, evsel);
    +
    + list_for_each_entry(pos, &evlist->entries, node) {
    + if (perf_evsel__open(pos, evlist->cpus, evlist->threads, 0) < 0) {
    + ret = -errno;
    + fprintf(stderr, "cannot open events, %d\n", ret);
    + goto out;
    + }
    + }
    +
    + if (perf_evlist__mmap(evlist, config->mmap_pages, false) < 0) {
    + ret = -errno;
    + fprintf(stderr, "failed to mmap with %d (%s)\n",
    + ret, strerror(ret));
    + goto out;
    + }
    +
    + /*
    + * Create the child task
    + */
    + if ((pid=fork()) == -1) {
    + ret = -errno;
    + fprintf(stderr, "cannot fork process\n");
    + goto out;
    + }
    +
    + if (pid == 0)
    + exit(child(config->argv));
    +
    + /*
    + * wait for the child to exec
    + */
    + ret = waitpid(pid, &status, WUNTRACED);
    + if (ret == -1)
    + err(1, "waitpid failed");
    +
    + if (WIFEXITED(status))
    + errx(1, "task %s [%d] exited already status %d\n",
    + config->argv[0], pid, WEXITSTATUS(status));
    +
    + /*
    + * effectively activate monitoring
    + */
    + ptrace(PTRACE_DETACH, pid, NULL, 0);
    +
    + signal(SIGCHLD, cld_handler);
    +
    + /*
    + * core loop
    + */
    + for (ret = 0; !ret; ) {
    + if (done && ready)
    + break;
    + ready = done;
    +
    + ret = poll(evlist->pollfd, evlist->nr_fds, done ? 0 : -1);
    +
    + if (ret > 0) {
    + ovfl_count += ret;
    + } else if (ret < 0) {
    + ret = -errno;
    + if (ret != -EINTR)
    + break;
    + ret = 0;
    + }
    +
    + list_for_each_entry(pos, &evlist->entries, node) {
    + if (ret < 0)
    + break;
    + ret = __perf_evsel__read(pos, evlist->cpus->nr,
    + evlist->threads->nr, false);
    + }
    +
    + for (idx = 0; !ret, idx < evlist->nr_fds; idx++) {
    + if (done)
    + ioctl(evlist->pollfd[idx].fd,
    + PERF_EVENT_IOC_DISABLE);
    + while (event = perf_evlist__mmap_read(evlist, idx)) {
    + ready = 0;
    + ret = perf_event__parse_sample(event,
    + evsel->attr.sample_type,
    + perf_evsel__sample_size(evsel),
    + false, &sample);
    + if (ret)
    + break;
    + collected_samples++;
    + if (print_ibs(&sample))
    + print_event(event);
    + }
    + }
    + }
    +
    + /*
    + * cleanup child
    + */
    + waitpid(pid, &status, 0);
    +
    + printf("%"PRIu64" samples collected in %"PRIu64" poll events, %"PRIu64" lost samples\n",
    + collected_samples, ovfl_count, lost_samples);
    + if (collected_samples)
    + printf("avg period=%"PRIu64"\n", sum_period / collected_samples);
    +out:
    + if (evlist) {
    + perf_evlist__munmap(evlist);
    + list_for_each_entry_safe(pos, n, &evlist->entries, node) {
    + perf_evsel__close_fd(pos, evlist->cpus->nr,
    + evlist->threads->nr);
    + list_del(&pos->node);
    + }
    + free(evsel->counts);
    + evsel->counts = NULL;
    + perf_evlist__delete_maps(evlist);
    + cpus = NULL;
    + threads = NULL;
    + }
    + free(evsel);
    + free(evlist);
    + free(cpus);
    + free(threads);
    +
    + return ret;
    +}
    +
    +int main(int argc, char **argv)
    +{
    + struct perf_config config;
    + int ret;
    +
    + ret = ibs_config(&config, argc, argv);
    + if (ret)
    + goto fail;
    + ret = ibs_run(&config);
    + if (ret)
    + goto fail;
    + return 0;
    +fail:
    + printf("An error occurred: %d (%s)\n", -ret, strerror(-ret));
    + return -1;
    +}
    --
    1.7.5.3



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