linux/Documentation/accounting/taskstats-struct.txt
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   1The struct taskstats
   2--------------------
   3
   4This document contains an explanation of the struct taskstats fields.
   5
   6There are three different groups of fields in the struct taskstats:
   7
   81) Common and basic accounting fields
   9    If CONFIG_TASKSTATS is set, the taskstats interface is enabled and
  10    the common fields and basic accounting fields are collected for
  11    delivery at do_exit() of a task.
  122) Delay accounting fields
  13    These fields are placed between
  14    /* Delay accounting fields start */
  15    and
  16    /* Delay accounting fields end */
  17    Their values are collected if CONFIG_TASK_DELAY_ACCT is set.
  183) Extended accounting fields
  19    These fields are placed between
  20    /* Extended accounting fields start */
  21    and
  22    /* Extended accounting fields end */
  23    Their values are collected if CONFIG_TASK_XACCT is set.
  24
  254) Per-task and per-thread context switch count statistics
  26
  275) Time accounting for SMT machines
  28
  296) Extended delay accounting fields for memory reclaim
  30
  31Future extension should add fields to the end of the taskstats struct, and
  32should not change the relative position of each field within the struct.
  33
  34
  35struct taskstats {
  36
  371) Common and basic accounting fields:
  38        /* The version number of this struct. This field is always set to
  39         * TAKSTATS_VERSION, which is defined in <linux/taskstats.h>.
  40         * Each time the struct is changed, the value should be incremented.
  41         */
  42        __u16   version;
  43
  44        /* The exit code of a task. */
  45        __u32   ac_exitcode;            /* Exit status */
  46
  47        /* The accounting flags of a task as defined in <linux/acct.h>
  48         * Defined values are AFORK, ASU, ACOMPAT, ACORE, and AXSIG.
  49         */
  50        __u8    ac_flag;                /* Record flags */
  51
  52        /* The value of task_nice() of a task. */
  53        __u8    ac_nice;                /* task_nice */
  54
  55        /* The name of the command that started this task. */
  56        char    ac_comm[TS_COMM_LEN];   /* Command name */
  57
  58        /* The scheduling discipline as set in task->policy field. */
  59        __u8    ac_sched;               /* Scheduling discipline */
  60
  61        __u8    ac_pad[3];
  62        __u32   ac_uid;                 /* User ID */
  63        __u32   ac_gid;                 /* Group ID */
  64        __u32   ac_pid;                 /* Process ID */
  65        __u32   ac_ppid;                /* Parent process ID */
  66
  67        /* The time when a task begins, in [secs] since 1970. */
  68        __u32   ac_btime;               /* Begin time [sec since 1970] */
  69
  70        /* The elapsed time of a task, in [usec]. */
  71        __u64   ac_etime;               /* Elapsed time [usec] */
  72
  73        /* The user CPU time of a task, in [usec]. */
  74        __u64   ac_utime;               /* User CPU time [usec] */
  75
  76        /* The system CPU time of a task, in [usec]. */
  77        __u64   ac_stime;               /* System CPU time [usec] */
  78
  79        /* The minor page fault count of a task, as set in task->min_flt. */
  80        __u64   ac_minflt;              /* Minor Page Fault Count */
  81
  82        /* The major page fault count of a task, as set in task->maj_flt. */
  83        __u64   ac_majflt;              /* Major Page Fault Count */
  84
  85
  862) Delay accounting fields:
  87        /* Delay accounting fields start
  88         *
  89         * All values, until the comment "Delay accounting fields end" are
  90         * available only if delay accounting is enabled, even though the last
  91         * few fields are not delays
  92         *
  93         * xxx_count is the number of delay values recorded
  94         * xxx_delay_total is the corresponding cumulative delay in nanoseconds
  95         *
  96         * xxx_delay_total wraps around to zero on overflow
  97         * xxx_count incremented regardless of overflow
  98         */
  99
 100        /* Delay waiting for cpu, while runnable
 101         * count, delay_total NOT updated atomically
 102         */
 103        __u64   cpu_count;
 104        __u64   cpu_delay_total;
 105
 106        /* Following four fields atomically updated using task->delays->lock */
 107
 108        /* Delay waiting for synchronous block I/O to complete
 109         * does not account for delays in I/O submission
 110         */
 111        __u64   blkio_count;
 112        __u64   blkio_delay_total;
 113
 114        /* Delay waiting for page fault I/O (swap in only) */
 115        __u64   swapin_count;
 116        __u64   swapin_delay_total;
 117
 118        /* cpu "wall-clock" running time
 119         * On some architectures, value will adjust for cpu time stolen
 120         * from the kernel in involuntary waits due to virtualization.
 121         * Value is cumulative, in nanoseconds, without a corresponding count
 122         * and wraps around to zero silently on overflow
 123         */
 124        __u64   cpu_run_real_total;
 125
 126        /* cpu "virtual" running time
 127         * Uses time intervals seen by the kernel i.e. no adjustment
 128         * for kernel's involuntary waits due to virtualization.
 129         * Value is cumulative, in nanoseconds, without a corresponding count
 130         * and wraps around to zero silently on overflow
 131         */
 132        __u64   cpu_run_virtual_total;
 133        /* Delay accounting fields end */
 134        /* version 1 ends here */
 135
 136
 1373) Extended accounting fields
 138        /* Extended accounting fields start */
 139
 140        /* Accumulated RSS usage in duration of a task, in MBytes-usecs.
 141         * The current rss usage is added to this counter every time
 142         * a tick is charged to a task's system time. So, at the end we
 143         * will have memory usage multiplied by system time. Thus an
 144         * average usage per system time unit can be calculated.
 145         */
 146        __u64   coremem;                /* accumulated RSS usage in MB-usec */
 147
 148        /* Accumulated virtual memory usage in duration of a task.
 149         * Same as acct_rss_mem1 above except that we keep track of VM usage.
 150         */
 151        __u64   virtmem;                /* accumulated VM usage in MB-usec */
 152
 153        /* High watermark of RSS usage in duration of a task, in KBytes. */
 154        __u64   hiwater_rss;            /* High-watermark of RSS usage */
 155
 156        /* High watermark of VM  usage in duration of a task, in KBytes. */
 157        __u64   hiwater_vm;             /* High-water virtual memory usage */
 158
 159        /* The following four fields are I/O statistics of a task. */
 160        __u64   read_char;              /* bytes read */
 161        __u64   write_char;             /* bytes written */
 162        __u64   read_syscalls;          /* read syscalls */
 163        __u64   write_syscalls;         /* write syscalls */
 164
 165        /* Extended accounting fields end */
 166
 1674) Per-task and per-thread statistics
 168        __u64   nvcsw;                  /* Context voluntary switch counter */
 169        __u64   nivcsw;                 /* Context involuntary switch counter */
 170
 1715) Time accounting for SMT machines
 172        __u64   ac_utimescaled;         /* utime scaled on frequency etc */
 173        __u64   ac_stimescaled;         /* stime scaled on frequency etc */
 174        __u64   cpu_scaled_run_real_total; /* scaled cpu_run_real_total */
 175
 1766) Extended delay accounting fields for memory reclaim
 177        /* Delay waiting for memory reclaim */
 178        __u64   freepages_count;
 179        __u64   freepages_delay_total;
 180}
 181
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