cmd/kvmstat/kvmstat.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 2011, Joyent, Inc. All rights reserved.
 */

#include <sys/kstat.h>
#include <kstat.h>
#include <stdlib.h>
#include <unistd.h>
#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <strings.h>
#include <alloca.h>
#include <signal.h>
#include <sys/varargs.h>
#include <sys/int_limits.h>

#define KSTAT_FIELD_USEINSTANCE     0x01
#define KSTAT_FIELD_NODELTA     0x02
#define KSTAT_FIELD_FILLER      0x04

typedef struct kstat_field {
    char *ksf_header;       /* header for field */
    char *ksf_name;         /* name of stat, if any */
    int ksf_width;          /* width for field in output line */
    uint32_t ksf_flags;     /* flags for this field, if any */
    int ksf_hint;           /* index hint for field in kstat */
} kstat_field_t;

typedef struct kstat_instance {
    char ksi_name[KSTAT_STRLEN];    /* name of the underlying kstat */
    int ksi_instance;       /* instance identifer of this kstat */
    kstat_t *ksi_ksp;       /* pointer to the kstat */
    uint64_t *ksi_data[2];      /* pointer to two generations of data */
    hrtime_t ksi_snaptime[2];   /* hrtime for data generations */
    int ksi_gen;            /* current generation */
    struct kstat_instance *ksi_next; /* next in instance list */
} kstat_instance_t;

const char *g_cmd = "kvmstat";

static void
fatal(char *fmt, ...)
{
    va_list ap;
    int error = errno;

    va_start(ap, fmt);

    (void) fprintf(stderr, "%s: ", g_cmd);
    /*LINTED*/
    (void) vfprintf(stderr, fmt, ap);

    if (fmt[strlen(fmt) - 1] != '\n')
        (void) fprintf(stderr, ": %s\n", strerror(error));

    exit(EXIT_FAILURE);
}

int
kstat_field_hint(kstat_t *ksp, kstat_field_t *field)
{
    kstat_named_t *nm = KSTAT_NAMED_PTR(ksp);
    int i;

    assert(ksp->ks_type == KSTAT_TYPE_NAMED);

    for (i = 0; i < ksp->ks_ndata; i++) {
        if (strcmp(field->ksf_name, nm[i].name) == 0)
            return (field->ksf_hint = i);
    }

    fatal("could not find field '%s' in %s:%d\n",
        field->ksf_name, ksp->ks_name, ksp->ks_instance);

    return (0);
}

int
kstat_instances_compare(const void *lhs, const void *rhs)
{
    kstat_instance_t *l = *((kstat_instance_t **)lhs);
    kstat_instance_t *r = *((kstat_instance_t **)rhs);
    int rval;

    if ((rval = strcmp(l->ksi_name, r->ksi_name)) != 0)
        return (rval);

    if (l->ksi_instance < r->ksi_instance)
        return (-1);

    if (l->ksi_instance > r->ksi_instance)
        return (1);

    return (0);
}

void
kstat_instances_update(kstat_ctl_t *kcp, kstat_instance_t **head,
    boolean_t (*interested)(kstat_t *))
{
    int ninstances = 0, i;
    kstat_instance_t **sorted, *ksi, *next;
    kstat_t *ksp;
    kid_t kid;

    if ((kid = kstat_chain_update(kcp)) == 0 && *head != NULL)
        return;

    if (kid == -1)
        fatal("failed to update kstat chain");

    for (ksi = *head; ksi != NULL; ksi = ksi->ksi_next)
        ksi->ksi_ksp = NULL;

    for (ksp = kcp->kc_chain; ksp != NULL; ksp = ksp->ks_next) {
        kstat_instance_t *last = NULL;

        if (!interested(ksp))
            continue;

        /*
         * Now look to see if we have this instance and name.  (Yes,
         * this is a linear search; we're assuming that this list is
         * modest in size.)
         */
        for (ksi = *head; ksi != NULL; ksi = ksi->ksi_next) {
            last = ksi;

            if (ksi->ksi_instance != ksp->ks_instance)
                continue;

            if (strcmp(ksi->ksi_name, ksp->ks_name) != 0)
                continue;

            ksi->ksi_ksp = ksp;
            ninstances++;
            break;
        }

        if (ksi != NULL)
            continue;

        if ((ksi = malloc(sizeof (kstat_instance_t))) == NULL)
            fatal("could not allocate memory for stat instance");

        bzero(ksi, sizeof (kstat_instance_t));
        (void) strlcpy(ksi->ksi_name, ksp->ks_name, KSTAT_STRLEN);
        ksi->ksi_instance = ksp->ks_instance;
        ksi->ksi_ksp = ksp;
        ksi->ksi_next = NULL;

        if (last == NULL) {
            assert(*head == NULL);
            *head = ksi;
        } else {
            last->ksi_next = ksi;
        }

        ninstances++;
    }

    /*
     * Now we know how many instances we have; iterate back over them,
     * pruning the stale ones and adding the active ones to a holding
     * array in which to sort them.
     */
    sorted = (void *)alloca(ninstances * sizeof (kstat_instance_t *));
    ninstances = 0;

    for (ksi = *head; ksi != NULL; ksi = next) {
        next = ksi->ksi_next;

        if (ksi->ksi_ksp == NULL) {
            free(ksi);
        } else {
            sorted[ninstances++] = ksi;
        }
    }

    if (ninstances == 0) {
        *head = NULL;
        return;
    }

    qsort(sorted, ninstances, sizeof (kstat_instance_t *),
        kstat_instances_compare);

    *head = sorted[0];

    for (i = 0; i < ninstances; i++) {
        ksi = sorted[i];
        ksi->ksi_next = i < ninstances - 1 ? sorted[i + 1] : NULL;
    }
}

void
kstat_instances_read(kstat_ctl_t *kcp, kstat_instance_t *instances,
    kstat_field_t *fields)
{
    kstat_instance_t *ksi;
    int i, nfields;

    for (nfields = 0; fields[nfields].ksf_header != NULL; nfields++)
        continue;

    for (ksi = instances; ksi != NULL; ksi = ksi->ksi_next) {
        kstat_t *ksp = ksi->ksi_ksp;

        if (ksp == NULL)
            continue;

        if (kstat_read(kcp, ksp, NULL) == -1) {
            if (errno == ENXIO) {
                /*
                 * Our kstat has been removed since the update;
                 * NULL it out to prevent us from trying to read
                 * it again (and to indicate that it should not
                 * be displayed) and drive on.
                 */
                ksi->ksi_ksp = NULL;
                continue;
            }

            fatal("failed to read kstat %s:%d",
                ksi->ksi_name, ksi->ksi_instance);
        }

        if (ksp->ks_type != KSTAT_TYPE_NAMED) {
            fatal("%s:%d is not a named kstat", ksi->ksi_name,
                ksi->ksi_instance);
        }

        if (ksi->ksi_data[0] == NULL) {
            size_t size = nfields * sizeof (uint64_t) * 2;
            uint64_t *data;

            if ((data = malloc(size)) == NULL)
                fatal("could not allocate memory");

            bzero(data, size);
            ksi->ksi_data[0] = data;
            ksi->ksi_data[1] = &data[nfields];
        }

        for (i = 0; i < nfields; i++) {
            kstat_named_t *nm = KSTAT_NAMED_PTR(ksp);
            kstat_field_t *field = &fields[i];
            int hint = field->ksf_hint;

            if (field->ksf_name == NULL)
                continue;

            if (hint < 0 || hint >= ksp->ks_ndata ||
                strcmp(field->ksf_name, nm[hint].name) != 0) {
                hint = kstat_field_hint(ksp, field);
            }

            ksi->ksi_data[ksi->ksi_gen][i] = nm[hint].value.ui64;
        }

        ksi->ksi_snaptime[ksi->ksi_gen] = ksp->ks_snaptime;
        ksi->ksi_gen ^= 1;
    }
}

uint64_t
kstat_instances_delta(kstat_instance_t *ksi, int i)
{
    int gen = ksi->ksi_gen;
    uint64_t delta = ksi->ksi_data[gen ^ 1][i] - ksi->ksi_data[gen][i];
    uint64_t tdelta = ksi->ksi_snaptime[gen ^ 1] - ksi->ksi_snaptime[gen];

    return (((delta * (uint64_t)NANOSEC) + (tdelta / 2)) / tdelta);
}

void
kstat_instances_print(kstat_instance_t *instances, kstat_field_t *fields,
    boolean_t header)
{
    kstat_instance_t *ksi = instances;
    int i, nfields;

    for (nfields = 0; fields[nfields].ksf_header != NULL; nfields++)
        continue;

    if (header) {
        for (i = 0; i < nfields; i++) {
            (void) printf("%*s%c", fields[i].ksf_width,
                fields[i].ksf_header, i < nfields - 1 ? ' ' : '\n');
        }
    }

    for (ksi = instances; ksi != NULL; ksi = ksi->ksi_next) {
        if (ksi->ksi_snaptime[1] == 0 || ksi->ksi_ksp == NULL)
            continue;

        for (i = 0; i < nfields; i++) {
            char trailer = i < nfields - 1 ? ' ' : '\n';

            if (fields[i].ksf_flags & KSTAT_FIELD_FILLER) {
                (void) printf("%*s%c", fields[i].ksf_width,
                    fields[i].ksf_header, trailer);
                continue;
            }

            (void) printf("%*lld%c", fields[i].ksf_width,
                fields[i].ksf_flags & KSTAT_FIELD_USEINSTANCE ?
                ksi->ksi_instance :
                fields[i].ksf_flags & KSTAT_FIELD_NODELTA ?
                ksi->ksi_data[ksi->ksi_gen ^ 1][i] :
                kstat_instances_delta(ksi, i), trailer);
        }
    }
}

boolean_t
interested(kstat_t *ksp)
{
    const char *module = "kvm";
    const char *class = "misc";
    const char *name = "vcpu-";

    if (strcmp(ksp->ks_module, module) != 0)
        return (B_FALSE);

    if (strcmp(ksp->ks_class, class) != 0)
        return (B_FALSE);

    if (strstr(ksp->ks_name, name) != ksp->ks_name)
        return (B_FALSE);

    return (B_TRUE);
}

/* BEGIN CSTYLED */
char *g_usage = "Usage: kvmstat [interval [count]]\n"
    "\n"
    "  Displays statistics for running kernel virtual machines, with one line\n"
    "  per virtual CPU.  All statistics are reported as per-second rates.\n"
    "\n"
    "  The columns are as follows:\n"
    "\n"
    "    pid    =>  identifier of process controlling the virtual CPU\n"
    "    vcpu   =>  virtual CPU identifier relative to its virtual machine\n"
    "    exits  =>  virtual machine exits for the virtual CPU\n"
    "    haltx  =>  virtual machine exits due to the HLT instruction\n"
    "    irqx   =>  virtual machine exits due to a pending external interrupt\n"
    "    irqwx  =>  virtual machine exits due to an open interrupt window\n"
    "    iox    =>  virtual machine exits due to an I/O instruction\n"
    "    mmiox  =>  virtual machine exits due to memory mapped I/O \n"
    "    irqs   =>  interrupts injected into the virtual CPU\n"
    "    emul   =>  instructions emulated in the kernel\n"
    "    eptv   =>  extended page table violations\n"
    "\n";
/* END CSTYLED */

void
usage()
{
    (void) fprintf(stderr, "%s", g_usage);
    exit(EXIT_FAILURE);
}

/*ARGSUSED*/
void
intr(int sig)
{}

/*ARGSUSED*/
int
main(int argc, char **argv)
{
    kstat_ctl_t *kcp;
    kstat_instance_t *instances = NULL;
    int i = 0;
    int interval = 1;
    int count = INT32_MAX;
    struct itimerval itimer;
    struct sigaction act;
    sigset_t set;
    char *endp;

    kstat_field_t fields[] =  {
        { "pid", "pid", 6, KSTAT_FIELD_NODELTA },
        { "vcpu", NULL, 4, KSTAT_FIELD_USEINSTANCE },
        { "|", NULL, 1, KSTAT_FIELD_FILLER },
        { "exits", "exits", 6 },
        { ":", NULL, 1, KSTAT_FIELD_FILLER },
        { "haltx", "halt-exits", 6 },
        { "irqx", "irq-exits", 6 },
        { "irqwx", "irq-window-exits", 6 },
        { "iox", "io-exits", 6 },
        { "mmiox", "mmio-exits", 6 },
        { "|", NULL, 1, KSTAT_FIELD_FILLER },
        { "irqs", "irq-injections", 6 },
        { "emul", "insn-emulation", 6 },
        { "eptv", "pf-fixed", 6 },
        { NULL }
    };

    if (argc > 1) {
        interval = strtol(argv[1], &endp, 10);

        if (*endp != '\0' || interval <= 0)
            usage();
    }

    if (argc > 2) {
        count = strtol(argv[2], &endp, 10);

        if (*endp != '\0' || count <= 0)
            usage();
    }

    if ((kcp = kstat_open()) == NULL)
        fatal("could not open /dev/kstat");

    (void) sigemptyset(&act.sa_mask);
    act.sa_flags = 0;
    act.sa_handler = intr;
    (void) sigaction(SIGALRM, &act, NULL);

    (void) sigemptyset(&set);
    (void) sigaddset(&set, SIGALRM);
    (void) sigprocmask(SIG_BLOCK, &set, NULL);

    bzero(&itimer, sizeof (itimer));
    itimer.it_value.tv_sec = interval;
    itimer.it_interval.tv_sec = interval;

    if (setitimer(ITIMER_REAL, &itimer, NULL) != 0) {
        fatal("could not set timer to %d second%s", interval,
            interval == 1 ? "" : "s");
    }

    (void) sigemptyset(&set);

    for (;;) {
        kstat_instances_update(kcp, &instances, interested);
        kstat_instances_read(kcp, instances, fields);

        if (i++ > 0) {
            kstat_instances_print(instances, fields,
                instances != NULL && instances->ksi_next == NULL ?
                (((i - 2) % 20) == 0) : B_TRUE);
        }

        if (i > count)
            break;

        (void) sigsuspend(&set);
    }

    /*NOTREACHED*/
    return (0);
}