perf-record.c

Go to the documentation of this file.

// SPDX-License-Identifier: GPL-2.0
#include <errno.h>
#include <inttypes.h>
/* For the CLR_() macros */
#include <pthread.h>

#include <sched.h>
#include "evlist.h"
#include "evsel.h"
#include "perf.h"
#include "debug.h"
#include "tests.h"

static int sched__get_first_possible_cpu(pid_t pid, cpu_set_t *maskp)
{
    int i, cpu = -1, nrcpus = 1024;
realloc:
    CPU_ZERO(maskp);

    if (sched_getaffinity(pid, sizeof(*maskp), maskp) == -1) {
        if (errno == EINVAL && nrcpus < (1024 << 8)) {
            nrcpus = nrcpus << 2;
            goto realloc;
        }
        perror("sched_getaffinity");
            return -1;
    }

    for (i = 0; i < nrcpus; i++) {
        if (CPU_ISSET(i, maskp)) {
            if (cpu == -1)
                cpu = i;
            else
                CPU_CLR(i, maskp);
        }
    }

    return cpu;
}

int test__PERF_RECORD(struct test *test __maybe_unused, int subtest __maybe_unused)
{
    struct record_opts opts = {
        .target = {
            .uid = UINT_MAX,
            .uses_mmap = true,
        },
        .no_buffering = true,
        .mmap_pages   = 256,
    };
    cpu_set_t cpu_mask;
    size_t cpu_mask_size = sizeof(cpu_mask);
    struct perf_evlist *evlist = perf_evlist__new_dummy();
    struct perf_evsel *evsel;
    struct perf_sample sample;
    const char *cmd = "sleep";
    const char *argv[] = { cmd, "1", NULL, };
    char *bname, *mmap_filename;
    u64 prev_time = 0;
    bool found_cmd_mmap = false,
         found_libc_mmap = false,
         found_vdso_mmap = false,
         found_ld_mmap = false;
    int err = -1, errs = 0, i, wakeups = 0;
    u32 cpu;
    int total_events = 0, nr_events[PERF_RECORD_MAX] = { 0, };
    char sbuf[STRERR_BUFSIZE];

    if (evlist == NULL) /* Fallback for kernels lacking PERF_COUNT_SW_DUMMY */
        evlist = perf_evlist__new_default();

    if (evlist == NULL) {
        pr_debug("Not enough memory to create evlist\n");
        goto out;
    }

    /*
     * Create maps of threads and cpus to monitor. In this case
     * we start with all threads and cpus (-1, -1) but then in
     * perf_evlist__prepare_workload we'll fill in the only thread
     * we're monitoring, the one forked there.
     */
    err = perf_evlist__create_maps(evlist, &opts.target);
    if (err < 0) {
        pr_debug("Not enough memory to create thread/cpu maps\n");
        goto out_delete_evlist;
    }

    /*
     * Prepare the workload in argv[] to run, it'll fork it, and then wait
     * for perf_evlist__start_workload() to exec it. This is done this way
     * so that we have time to open the evlist (calling sys_perf_event_open
     * on all the fds) and then mmap them.
     */
    err = perf_evlist__prepare_workload(evlist, &opts.target, argv, false, NULL);
    if (err < 0) {
        pr_debug("Couldn't run the workload!\n");
        goto out_delete_evlist;
    }

    /*
     * Config the evsels, setting attr->comm on the first one, etc.
     */
    evsel = perf_evlist__first(evlist);
    perf_evsel__set_sample_bit(evsel, CPU);
    perf_evsel__set_sample_bit(evsel, TID);
    perf_evsel__set_sample_bit(evsel, TIME);
    perf_evlist__config(evlist, &opts, NULL);

    err = sched__get_first_possible_cpu(evlist->workload.pid, &cpu_mask);
    if (err < 0) {
        pr_debug("sched__get_first_possible_cpu: %s\n",
             str_error_r(errno, sbuf, sizeof(sbuf)));
        goto out_delete_evlist;
    }

    cpu = err;

    /*
     * So that we can check perf_sample.cpu on all the samples.
     */
    if (sched_setaffinity(evlist->workload.pid, cpu_mask_size, &cpu_mask) < 0) {
        pr_debug("sched_setaffinity: %s\n",
             str_error_r(errno, sbuf, sizeof(sbuf)));
        goto out_delete_evlist;
    }

    /*
     * Call sys_perf_event_open on all the fds on all the evsels,
     * grouping them if asked to.
     */
    err = perf_evlist__open(evlist);
    if (err < 0) {
        pr_debug("perf_evlist__open: %s\n",
             str_error_r(errno, sbuf, sizeof(sbuf)));
        goto out_delete_evlist;
    }

    /*
     * mmap the first fd on a given CPU and ask for events for the other
     * fds in the same CPU to be injected in the same mmap ring buffer
     * (using ioctl(PERF_EVENT_IOC_SET_OUTPUT)).
     */
    err = perf_evlist__mmap(evlist, opts.mmap_pages);
    if (err < 0) {
        pr_debug("perf_evlist__mmap: %s\n",
             str_error_r(errno, sbuf, sizeof(sbuf)));
        goto out_delete_evlist;
    }

    /*
     * Now that all is properly set up, enable the events, they will
     * count just on workload.pid, which will start...
     */
    perf_evlist__enable(evlist);

    /*
     * Now!
     */
    perf_evlist__start_workload(evlist);

    while (1) {
        int before = total_events;

        for (i = 0; i < evlist->nr_mmaps; i++) {
            union perf_event *event;
            struct perf_mmap *md;

            md = &evlist->mmap[i];
            if (perf_mmap__read_init(md) < 0)
                continue;

            while ((event = perf_mmap__read_event(md)) != NULL) {
                const u32 type = event->header.type;
                const char *name = perf_event__name(type);

                ++total_events;
                if (type < PERF_RECORD_MAX)
                    nr_events[type]++;

                err = perf_evlist__parse_sample(evlist, event, &sample);
                if (err < 0) {
                    if (verbose > 0)
                        perf_event__fprintf(event, stderr);
                    pr_debug("Couldn't parse sample\n");
                    goto out_delete_evlist;
                }

                if (verbose > 0) {
                    pr_info("%" PRIu64" %d ", sample.time, sample.cpu);
                    perf_event__fprintf(event, stderr);
                }

                if (prev_time > sample.time) {
                    pr_debug("%s going backwards in time, prev=%" PRIu64 ", curr=%" PRIu64 "\n",
                         name, prev_time, sample.time);
                    ++errs;
                }

                prev_time = sample.time;

                if (sample.cpu != cpu) {
                    pr_debug("%s with unexpected cpu, expected %d, got %d\n",
                         name, cpu, sample.cpu);
                    ++errs;
                }

                if ((pid_t)sample.pid != evlist->workload.pid) {
                    pr_debug("%s with unexpected pid, expected %d, got %d\n",
                         name, evlist->workload.pid, sample.pid);
                    ++errs;
                }

                if ((pid_t)sample.tid != evlist->workload.pid) {
                    pr_debug("%s with unexpected tid, expected %d, got %d\n",
                         name, evlist->workload.pid, sample.tid);
                    ++errs;
                }

                if ((type == PERF_RECORD_COMM ||
                     type == PERF_RECORD_MMAP ||
                     type == PERF_RECORD_MMAP2 ||
                     type == PERF_RECORD_FORK ||
                     type == PERF_RECORD_EXIT) &&
                     (pid_t)event->comm.pid != evlist->workload.pid) {
                    pr_debug("%s with unexpected pid/tid\n", name);
                    ++errs;
                }

                if ((type == PERF_RECORD_COMM ||
                     type == PERF_RECORD_MMAP ||
                     type == PERF_RECORD_MMAP2) &&
                     event->comm.pid != event->comm.tid) {
                    pr_debug("%s with different pid/tid!\n", name);
                    ++errs;
                }

                switch (type) {
                case PERF_RECORD_COMM:
                    if (strcmp(event->comm.comm, cmd)) {
                        pr_debug("%s with unexpected comm!\n", name);
                        ++errs;
                    }
                    break;
                case PERF_RECORD_EXIT:
                    goto found_exit;
                case PERF_RECORD_MMAP:
                    mmap_filename = event->mmap.filename;
                    goto check_bname;
                case PERF_RECORD_MMAP2:
                    mmap_filename = event->mmap2.filename;
                check_bname:
                    bname = strrchr(mmap_filename, '/');
                    if (bname != NULL) {
                        if (!found_cmd_mmap)
                            found_cmd_mmap = !strcmp(bname + 1, cmd);
                        if (!found_libc_mmap)
                            found_libc_mmap = !strncmp(bname + 1, "libc", 4);
                        if (!found_ld_mmap)
                            found_ld_mmap = !strncmp(bname + 1, "ld", 2);
                    } else if (!found_vdso_mmap)
                        found_vdso_mmap = !strcmp(mmap_filename, "[vdso]");
                    break;

                case PERF_RECORD_SAMPLE:
                    /* Just ignore samples for now */
                    break;
                default:
                    pr_debug("Unexpected perf_event->header.type %d!\n",
                         type);
                    ++errs;
                }

                perf_mmap__consume(md);
            }
            perf_mmap__read_done(md);
        }

        /*
         * We don't use poll here because at least at 3.1 times the
         * PERF_RECORD_{!SAMPLE} events don't honour
         * perf_event_attr.wakeup_events, just PERF_EVENT_SAMPLE does.
         */
        if (total_events == before && false)
            perf_evlist__poll(evlist, -1);

        sleep(1);
        if (++wakeups > 5) {
            pr_debug("No PERF_RECORD_EXIT event!\n");
            break;
        }
    }

found_exit:
    if (nr_events[PERF_RECORD_COMM] > 1) {
        pr_debug("Excessive number of PERF_RECORD_COMM events!\n");
        ++errs;
    }

    if (nr_events[PERF_RECORD_COMM] == 0) {
        pr_debug("Missing PERF_RECORD_COMM for %s!\n", cmd);
        ++errs;
    }

    if (!found_cmd_mmap) {
        pr_debug("PERF_RECORD_MMAP for %s missing!\n", cmd);
        ++errs;
    }

    if (!found_libc_mmap) {
        pr_debug("PERF_RECORD_MMAP for %s missing!\n", "libc");
        ++errs;
    }

    if (!found_ld_mmap) {
        pr_debug("PERF_RECORD_MMAP for %s missing!\n", "ld");
        ++errs;
    }

    if (!found_vdso_mmap) {
        pr_debug("PERF_RECORD_MMAP for %s missing!\n", "[vdso]");
        ++errs;
    }
out_delete_evlist:
    perf_evlist__delete(evlist);
out:
    return (err < 0 || errs > 0) ? -1 : 0;
}