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getdelays.c

/* getdelays.c
 *
 * Utility to get per-pid and per-tgid delay accounting statistics
 * Also illustrates usage of the taskstats interface
 *
 * Copyright (C) Shailabh Nagar, IBM Corp. 2005
 * Copyright (C) Balbir Singh, IBM Corp. 2006
 * Copyright (c) Jay Lan, SGI. 2006
 *
 * Compile with
 *    gcc -I/usr/src/linux/include getdelays.c -o getdelays
 */

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <poll.h>
#include <string.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <signal.h>

#include <linux/genetlink.h>
#include <linux/taskstats.h>
#include <linux/cgroupstats.h>

/*
 * Generic macros for dealing with netlink sockets. Might be duplicated
 * elsewhere. It is recommended that commercial grade applications use
 * libnl or libnetlink and use the interfaces provided by the library
 */
#define GENLMSG_DATA(glh)     ((void *)(NLMSG_DATA(glh) + GENL_HDRLEN))
#define GENLMSG_PAYLOAD(glh)  (NLMSG_PAYLOAD(glh, 0) - GENL_HDRLEN)
#define NLA_DATA(na)          ((void *)((char*)(na) + NLA_HDRLEN))
#define NLA_PAYLOAD(len)      (len - NLA_HDRLEN)

#define err(code, fmt, arg...)                  \
      do {                          \
            fprintf(stderr, fmt, ##arg);  \
            exit(code);             \
      } while (0)

int done;
int rcvbufsz;
char name[100];
int dbg;
int print_delays;
int print_io_accounting;
int print_task_context_switch_counts;
__u64 stime, utime;

#define PRINTF(fmt, arg...) {             \
          if (dbg) {                      \
            printf(fmt, ##arg);           \
          }                         \
      }

/* Maximum size of response requested or message sent */
#define MAX_MSG_SIZE    1024
/* Maximum number of cpus expected to be specified in a cpumask */
#define MAX_CPUS  32

struct msgtemplate {
      struct nlmsghdr n;
      struct genlmsghdr g;
      char buf[MAX_MSG_SIZE];
};

char cpumask[100+6*MAX_CPUS];

static void usage(void)
{
      fprintf(stderr, "getdelays [-dilv] [-w logfile] [-r bufsize] "
                  "[-m cpumask] [-t tgid] [-p pid]\n");
      fprintf(stderr, "  -d: print delayacct stats\n");
      fprintf(stderr, "  -i: print IO accounting (works only with -p)\n");
      fprintf(stderr, "  -l: listen forever\n");
      fprintf(stderr, "  -v: debug on\n");
      fprintf(stderr, "  -C: container path\n");
}

/*
 * Create a raw netlink socket and bind
 */
static int create_nl_socket(int protocol)
{
      int fd;
      struct sockaddr_nl local;

      fd = socket(AF_NETLINK, SOCK_RAW, protocol);
      if (fd < 0)
            return -1;

      if (rcvbufsz)
            if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF,
                        &rcvbufsz, sizeof(rcvbufsz)) < 0) {
                  fprintf(stderr, "Unable to set socket rcv buf size "
                              "to %d\n",
                        rcvbufsz);
                  return -1;
            }

      memset(&local, 0, sizeof(local));
      local.nl_family = AF_NETLINK;

      if (bind(fd, (struct sockaddr *) &local, sizeof(local)) < 0)
            goto error;

      return fd;
error:
      close(fd);
      return -1;
}


int send_cmd(int sd, __u16 nlmsg_type, __u32 nlmsg_pid,
           __u8 genl_cmd, __u16 nla_type,
           void *nla_data, int nla_len)
{
      struct nlattr *na;
      struct sockaddr_nl nladdr;
      int r, buflen;
      char *buf;

      struct msgtemplate msg;

      msg.n.nlmsg_len = NLMSG_LENGTH(GENL_HDRLEN);
      msg.n.nlmsg_type = nlmsg_type;
      msg.n.nlmsg_flags = NLM_F_REQUEST;
      msg.n.nlmsg_seq = 0;
      msg.n.nlmsg_pid = nlmsg_pid;
      msg.g.cmd = genl_cmd;
      msg.g.version = 0x1;
      na = (struct nlattr *) GENLMSG_DATA(&msg);
      na->nla_type = nla_type;
      na->nla_len = nla_len + 1 + NLA_HDRLEN;
      memcpy(NLA_DATA(na), nla_data, nla_len);
      msg.n.nlmsg_len += NLMSG_ALIGN(na->nla_len);

      buf = (char *) &msg;
      buflen = msg.n.nlmsg_len ;
      memset(&nladdr, 0, sizeof(nladdr));
      nladdr.nl_family = AF_NETLINK;
      while ((r = sendto(sd, buf, buflen, 0, (struct sockaddr *) &nladdr,
                     sizeof(nladdr))) < buflen) {
            if (r > 0) {
                  buf += r;
                  buflen -= r;
            } else if (errno != EAGAIN)
                  return -1;
      }
      return 0;
}


/*
 * Probe the controller in genetlink to find the family id
 * for the TASKSTATS family
 */
int get_family_id(int sd)
{
      struct {
            struct nlmsghdr n;
            struct genlmsghdr g;
            char buf[256];
      } ans;

      int id, rc;
      struct nlattr *na;
      int rep_len;

      strcpy(name, TASKSTATS_GENL_NAME);
      rc = send_cmd(sd, GENL_ID_CTRL, getpid(), CTRL_CMD_GETFAMILY,
                  CTRL_ATTR_FAMILY_NAME, (void *)name,
                  strlen(TASKSTATS_GENL_NAME)+1);

      rep_len = recv(sd, &ans, sizeof(ans), 0);
      if (ans.n.nlmsg_type == NLMSG_ERROR ||
          (rep_len < 0) || !NLMSG_OK((&ans.n), rep_len))
            return 0;

      na = (struct nlattr *) GENLMSG_DATA(&ans);
      na = (struct nlattr *) ((char *) na + NLA_ALIGN(na->nla_len));
      if (na->nla_type == CTRL_ATTR_FAMILY_ID) {
            id = *(__u16 *) NLA_DATA(na);
      }
      return id;
}

void print_delayacct(struct taskstats *t)
{
      printf("\n\nCPU   %15s%15s%15s%15s\n"
             "      %15llu%15llu%15llu%15llu\n"
             "IO    %15s%15s\n"
             "      %15llu%15llu\n"
             "MEM   %15s%15s\n"
             "      %15llu%15llu\n",
             "count", "real total", "virtual total", "delay total",
             t->cpu_count, t->cpu_run_real_total, t->cpu_run_virtual_total,
             t->cpu_delay_total,
             "count", "delay total",
             t->blkio_count, t->blkio_delay_total,
             "count", "delay total", t->swapin_count, t->swapin_delay_total);
}

void task_context_switch_counts(struct taskstats *t)
{
      printf("\n\nTask   %15s%15s\n"
             "       %15lu%15lu\n",
             "voluntary", "nonvoluntary",
             t->nvcsw, t->nivcsw);
}

void print_cgroupstats(struct cgroupstats *c)
{
      printf("sleeping %llu, blocked %llu, running %llu, stopped %llu, "
            "uninterruptible %llu\n", c->nr_sleeping, c->nr_io_wait,
            c->nr_running, c->nr_stopped, c->nr_uninterruptible);
}


void print_ioacct(struct taskstats *t)
{
      printf("%s: read=%llu, write=%llu, cancelled_write=%llu\n",
            t->ac_comm,
            (unsigned long long)t->read_bytes,
            (unsigned long long)t->write_bytes,
            (unsigned long long)t->cancelled_write_bytes);
}

int main(int argc, char *argv[])
{
      int c, rc, rep_len, aggr_len, len2, cmd_type;
      __u16 id;
      __u32 mypid;

      struct nlattr *na;
      int nl_sd = -1;
      int len = 0;
      pid_t tid = 0;
      pid_t rtid = 0;

      int fd = 0;
      int count = 0;
      int write_file = 0;
      int maskset = 0;
      char *logfile = NULL;
      int loop = 0;
      int containerset = 0;
      char containerpath[1024];
      int cfd = 0;

      struct msgtemplate msg;

      while (1) {
            c = getopt(argc, argv, "qdiw:r:m:t:p:vlC:");
            if (c < 0)
                  break;

            switch (c) {
            case 'd':
                  printf("print delayacct stats ON\n");
                  print_delays = 1;
                  break;
            case 'i':
                  printf("printing IO accounting\n");
                  print_io_accounting = 1;
                  break;
            case 'q':
                  printf("printing task/process context switch rates\n");
                  print_task_context_switch_counts = 1;
                  break;
            case 'C':
                  containerset = 1;
                  strncpy(containerpath, optarg, strlen(optarg) + 1);
                  break;
            case 'w':
                  logfile = strdup(optarg);
                  printf("write to file %s\n", logfile);
                  write_file = 1;
                  break;
            case 'r':
                  rcvbufsz = atoi(optarg);
                  printf("receive buf size %d\n", rcvbufsz);
                  if (rcvbufsz < 0)
                        err(1, "Invalid rcv buf size\n");
                  break;
            case 'm':
                  strncpy(cpumask, optarg, sizeof(cpumask));
                  maskset = 1;
                  printf("cpumask %s maskset %d\n", cpumask, maskset);
                  break;
            case 't':
                  tid = atoi(optarg);
                  if (!tid)
                        err(1, "Invalid tgid\n");
                  cmd_type = TASKSTATS_CMD_ATTR_TGID;
                  break;
            case 'p':
                  tid = atoi(optarg);
                  if (!tid)
                        err(1, "Invalid pid\n");
                  cmd_type = TASKSTATS_CMD_ATTR_PID;
                  break;
            case 'v':
                  printf("debug on\n");
                  dbg = 1;
                  break;
            case 'l':
                  printf("listen forever\n");
                  loop = 1;
                  break;
            default:
                  usage();
                  exit(-1);
            }
      }

      if (write_file) {
            fd = open(logfile, O_WRONLY | O_CREAT | O_TRUNC,
                    S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
            if (fd == -1) {
                  perror("Cannot open output file\n");
                  exit(1);
            }
      }

      if ((nl_sd = create_nl_socket(NETLINK_GENERIC)) < 0)
            err(1, "error creating Netlink socket\n");


      mypid = getpid();
      id = get_family_id(nl_sd);
      if (!id) {
            fprintf(stderr, "Error getting family id, errno %d\n", errno);
            goto err;
      }
      PRINTF("family id %d\n", id);

      if (maskset) {
            rc = send_cmd(nl_sd, id, mypid, TASKSTATS_CMD_GET,
                        TASKSTATS_CMD_ATTR_REGISTER_CPUMASK,
                        &cpumask, strlen(cpumask) + 1);
            PRINTF("Sent register cpumask, retval %d\n", rc);
            if (rc < 0) {
                  fprintf(stderr, "error sending register cpumask\n");
                  goto err;
            }
      }

      if (tid && containerset) {
            fprintf(stderr, "Select either -t or -C, not both\n");
            goto err;
      }

      if (tid) {
            rc = send_cmd(nl_sd, id, mypid, TASKSTATS_CMD_GET,
                        cmd_type, &tid, sizeof(__u32));
            PRINTF("Sent pid/tgid, retval %d\n", rc);
            if (rc < 0) {
                  fprintf(stderr, "error sending tid/tgid cmd\n");
                  goto done;
            }
      }

      if (containerset) {
            cfd = open(containerpath, O_RDONLY);
            if (cfd < 0) {
                  perror("error opening container file");
                  goto err;
            }
            rc = send_cmd(nl_sd, id, mypid, CGROUPSTATS_CMD_GET,
                        CGROUPSTATS_CMD_ATTR_FD, &cfd, sizeof(__u32));
            if (rc < 0) {
                  perror("error sending cgroupstats command");
                  goto err;
            }
      }

      do {
            int i;

            rep_len = recv(nl_sd, &msg, sizeof(msg), 0);
            PRINTF("received %d bytes\n", rep_len);

            if (rep_len < 0) {
                  fprintf(stderr, "nonfatal reply error: errno %d\n",
                        errno);
                  continue;
            }
            if (msg.n.nlmsg_type == NLMSG_ERROR ||
                !NLMSG_OK((&msg.n), rep_len)) {
                  struct nlmsgerr *err = NLMSG_DATA(&msg);
                  fprintf(stderr, "fatal reply error,  errno %d\n",
                        err->error);
                  goto done;
            }

            PRINTF("nlmsghdr size=%d, nlmsg_len=%d, rep_len=%d\n",
                   sizeof(struct nlmsghdr), msg.n.nlmsg_len, rep_len);


            rep_len = GENLMSG_PAYLOAD(&msg.n);

            na = (struct nlattr *) GENLMSG_DATA(&msg);
            len = 0;
            i = 0;
            while (len < rep_len) {
                  len += NLA_ALIGN(na->nla_len);
                  switch (na->nla_type) {
                  case TASKSTATS_TYPE_AGGR_TGID:
                        /* Fall through */
                  case TASKSTATS_TYPE_AGGR_PID:
                        aggr_len = NLA_PAYLOAD(na->nla_len);
                        len2 = 0;
                        /* For nested attributes, na follows */
                        na = (struct nlattr *) NLA_DATA(na);
                        done = 0;
                        while (len2 < aggr_len) {
                              switch (na->nla_type) {
                              case TASKSTATS_TYPE_PID:
                                    rtid = *(int *) NLA_DATA(na);
                                    if (print_delays)
                                          printf("PID\t%d\n", rtid);
                                    break;
                              case TASKSTATS_TYPE_TGID:
                                    rtid = *(int *) NLA_DATA(na);
                                    if (print_delays)
                                          printf("TGID\t%d\n", rtid);
                                    break;
                              case TASKSTATS_TYPE_STATS:
                                    count++;
                                    if (print_delays)
                                          print_delayacct((struct taskstats *) NLA_DATA(na));
                                    if (print_io_accounting)
                                          print_ioacct((struct taskstats *) NLA_DATA(na));
                                    if (print_task_context_switch_counts)
                                          task_context_switch_counts((struct taskstats *) NLA_DATA(na));
                                    if (fd) {
                                          if (write(fd, NLA_DATA(na), na->nla_len) < 0) {
                                                err(1,"write error\n");
                                          }
                                    }
                                    if (!loop)
                                          goto done;
                                    break;
                              default:
                                    fprintf(stderr, "Unknown nested"
                                          " nla_type %d\n",
                                          na->nla_type);
                                    break;
                              }
                              len2 += NLA_ALIGN(na->nla_len);
                              na = (struct nlattr *) ((char *) na + len2);
                        }
                        break;

                  case CGROUPSTATS_TYPE_CGROUP_STATS:
                        print_cgroupstats(NLA_DATA(na));
                        break;
                  default:
                        fprintf(stderr, "Unknown nla_type %d\n",
                              na->nla_type);
                        break;
                  }
                  na = (struct nlattr *) (GENLMSG_DATA(&msg) + len);
            }
      } while (loop);
done:
      if (maskset) {
            rc = send_cmd(nl_sd, id, mypid, TASKSTATS_CMD_GET,
                        TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK,
                        &cpumask, strlen(cpumask) + 1);
            printf("Sent deregister mask, retval %d\n", rc);
            if (rc < 0)
                  err(rc, "error sending deregister cpumask\n");
      }
err:
      close(nl_sd);
      if (fd)
            close(fd);
      if (cfd)
            close(cfd);
      return 0;
}

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