0001 ====================
0002 The struct taskstats
0003 ====================
0004
0005 This document contains an explanation of the struct taskstats fields.
0006
0007 There are three different groups of fields in the struct taskstats:
0008
0009 1) Common and basic accounting fields
0010 If CONFIG_TASKSTATS is set, the taskstats interface is enabled and
0011 the common fields and basic accounting fields are collected for
0012 delivery at do_exit() of a task.
0013 2) Delay accounting fields
0014 These fields are placed between::
0015
0016 /* Delay accounting fields start */
0017
0018 and::
0019
0020 /* Delay accounting fields end */
0021
0022 Their values are collected if CONFIG_TASK_DELAY_ACCT is set.
0023 3) Extended accounting fields
0024 These fields are placed between::
0025
0026 /* Extended accounting fields start */
0027
0028 and::
0029
0030 /* Extended accounting fields end */
0031
0032 Their values are collected if CONFIG_TASK_XACCT is set.
0033
0034 4) Per-task and per-thread context switch count statistics
0035
0036 5) Time accounting for SMT machines
0037
0038 6) Extended delay accounting fields for memory reclaim
0039
0040 Future extension should add fields to the end of the taskstats struct, and
0041 should not change the relative position of each field within the struct.
0042
0043 ::
0044
0045 struct taskstats {
0046
0047 1) Common and basic accounting fields::
0048
0049 /* The version number of this struct. This field is always set to
0050 * TAKSTATS_VERSION, which is defined in <linux/taskstats.h>.
0051 * Each time the struct is changed, the value should be incremented.
0052 */
0053 __u16 version;
0054
0055 /* The exit code of a task. */
0056 __u32 ac_exitcode; /* Exit status */
0057
0058 /* The accounting flags of a task as defined in <linux/acct.h>
0059 * Defined values are AFORK, ASU, ACOMPAT, ACORE, and AXSIG.
0060 */
0061 __u8 ac_flag; /* Record flags */
0062
0063 /* The value of task_nice() of a task. */
0064 __u8 ac_nice; /* task_nice */
0065
0066 /* The name of the command that started this task. */
0067 char ac_comm[TS_COMM_LEN]; /* Command name */
0068
0069 /* The scheduling discipline as set in task->policy field. */
0070 __u8 ac_sched; /* Scheduling discipline */
0071
0072 __u8 ac_pad[3];
0073 __u32 ac_uid; /* User ID */
0074 __u32 ac_gid; /* Group ID */
0075 __u32 ac_pid; /* Process ID */
0076 __u32 ac_ppid; /* Parent process ID */
0077
0078 /* The time when a task begins, in [secs] since 1970. */
0079 __u32 ac_btime; /* Begin time [sec since 1970] */
0080
0081 /* The elapsed time of a task, in [usec]. */
0082 __u64 ac_etime; /* Elapsed time [usec] */
0083
0084 /* The user CPU time of a task, in [usec]. */
0085 __u64 ac_utime; /* User CPU time [usec] */
0086
0087 /* The system CPU time of a task, in [usec]. */
0088 __u64 ac_stime; /* System CPU time [usec] */
0089
0090 /* The minor page fault count of a task, as set in task->min_flt. */
0091 __u64 ac_minflt; /* Minor Page Fault Count */
0092
0093 /* The major page fault count of a task, as set in task->maj_flt. */
0094 __u64 ac_majflt; /* Major Page Fault Count */
0095
0096
0097 2) Delay accounting fields::
0098
0099 /* Delay accounting fields start
0100 *
0101 * All values, until the comment "Delay accounting fields end" are
0102 * available only if delay accounting is enabled, even though the last
0103 * few fields are not delays
0104 *
0105 * xxx_count is the number of delay values recorded
0106 * xxx_delay_total is the corresponding cumulative delay in nanoseconds
0107 *
0108 * xxx_delay_total wraps around to zero on overflow
0109 * xxx_count incremented regardless of overflow
0110 */
0111
0112 /* Delay waiting for cpu, while runnable
0113 * count, delay_total NOT updated atomically
0114 */
0115 __u64 cpu_count;
0116 __u64 cpu_delay_total;
0117
0118 /* Following four fields atomically updated using task->delays->lock */
0119
0120 /* Delay waiting for synchronous block I/O to complete
0121 * does not account for delays in I/O submission
0122 */
0123 __u64 blkio_count;
0124 __u64 blkio_delay_total;
0125
0126 /* Delay waiting for page fault I/O (swap in only) */
0127 __u64 swapin_count;
0128 __u64 swapin_delay_total;
0129
0130 /* cpu "wall-clock" running time
0131 * On some architectures, value will adjust for cpu time stolen
0132 * from the kernel in involuntary waits due to virtualization.
0133 * Value is cumulative, in nanoseconds, without a corresponding count
0134 * and wraps around to zero silently on overflow
0135 */
0136 __u64 cpu_run_real_total;
0137
0138 /* cpu "virtual" running time
0139 * Uses time intervals seen by the kernel i.e. no adjustment
0140 * for kernel's involuntary waits due to virtualization.
0141 * Value is cumulative, in nanoseconds, without a corresponding count
0142 * and wraps around to zero silently on overflow
0143 */
0144 __u64 cpu_run_virtual_total;
0145 /* Delay accounting fields end */
0146 /* version 1 ends here */
0147
0148
0149 3) Extended accounting fields::
0150
0151 /* Extended accounting fields start */
0152
0153 /* Accumulated RSS usage in duration of a task, in MBytes-usecs.
0154 * The current rss usage is added to this counter every time
0155 * a tick is charged to a task's system time. So, at the end we
0156 * will have memory usage multiplied by system time. Thus an
0157 * average usage per system time unit can be calculated.
0158 */
0159 __u64 coremem; /* accumulated RSS usage in MB-usec */
0160
0161 /* Accumulated virtual memory usage in duration of a task.
0162 * Same as acct_rss_mem1 above except that we keep track of VM usage.
0163 */
0164 __u64 virtmem; /* accumulated VM usage in MB-usec */
0165
0166 /* High watermark of RSS usage in duration of a task, in KBytes. */
0167 __u64 hiwater_rss; /* High-watermark of RSS usage */
0168
0169 /* High watermark of VM usage in duration of a task, in KBytes. */
0170 __u64 hiwater_vm; /* High-water virtual memory usage */
0171
0172 /* The following four fields are I/O statistics of a task. */
0173 __u64 read_char; /* bytes read */
0174 __u64 write_char; /* bytes written */
0175 __u64 read_syscalls; /* read syscalls */
0176 __u64 write_syscalls; /* write syscalls */
0177
0178 /* Extended accounting fields end */
0179
0180 4) Per-task and per-thread statistics::
0181
0182 __u64 nvcsw; /* Context voluntary switch counter */
0183 __u64 nivcsw; /* Context involuntary switch counter */
0184
0185 5) Time accounting for SMT machines::
0186
0187 __u64 ac_utimescaled; /* utime scaled on frequency etc */
0188 __u64 ac_stimescaled; /* stime scaled on frequency etc */
0189 __u64 cpu_scaled_run_real_total; /* scaled cpu_run_real_total */
0190
0191 6) Extended delay accounting fields for memory reclaim::
0192
0193 /* Delay waiting for memory reclaim */
0194 __u64 freepages_count;
0195 __u64 freepages_delay_total;
0196
0197 ::
0198
0199 }
