200 lines
6.0 KiB
ReStructuredText
200 lines
6.0 KiB
ReStructuredText
====================
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The struct taskstats
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====================
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This document contains an explanation of the struct taskstats fields.
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There are three different groups of fields in the struct taskstats:
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1) Common and basic accounting fields
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If CONFIG_TASKSTATS is set, the taskstats interface is enabled and
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the common fields and basic accounting fields are collected for
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delivery at do_exit() of a task.
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2) Delay accounting fields
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These fields are placed between::
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/* Delay accounting fields start */
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and::
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/* Delay accounting fields end */
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Their values are collected if CONFIG_TASK_DELAY_ACCT is set.
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3) Extended accounting fields
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These fields are placed between::
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/* Extended accounting fields start */
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and::
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/* Extended accounting fields end */
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Their values are collected if CONFIG_TASK_XACCT is set.
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4) Per-task and per-thread context switch count statistics
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5) Time accounting for SMT machines
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6) Extended delay accounting fields for memory reclaim
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Future extension should add fields to the end of the taskstats struct, and
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should not change the relative position of each field within the struct.
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::
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struct taskstats {
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1) Common and basic accounting fields::
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/* The version number of this struct. This field is always set to
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* TAKSTATS_VERSION, which is defined in <linux/taskstats.h>.
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* Each time the struct is changed, the value should be incremented.
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*/
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__u16 version;
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/* The exit code of a task. */
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__u32 ac_exitcode; /* Exit status */
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/* The accounting flags of a task as defined in <linux/acct.h>
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* Defined values are AFORK, ASU, ACOMPAT, ACORE, and AXSIG.
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*/
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__u8 ac_flag; /* Record flags */
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/* The value of task_nice() of a task. */
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__u8 ac_nice; /* task_nice */
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/* The name of the command that started this task. */
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char ac_comm[TS_COMM_LEN]; /* Command name */
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/* The scheduling discipline as set in task->policy field. */
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__u8 ac_sched; /* Scheduling discipline */
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__u8 ac_pad[3];
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__u32 ac_uid; /* User ID */
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__u32 ac_gid; /* Group ID */
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__u32 ac_pid; /* Process ID */
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__u32 ac_ppid; /* Parent process ID */
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/* The time when a task begins, in [secs] since 1970. */
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__u32 ac_btime; /* Begin time [sec since 1970] */
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/* The elapsed time of a task, in [usec]. */
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__u64 ac_etime; /* Elapsed time [usec] */
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/* The user CPU time of a task, in [usec]. */
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__u64 ac_utime; /* User CPU time [usec] */
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/* The system CPU time of a task, in [usec]. */
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__u64 ac_stime; /* System CPU time [usec] */
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/* The minor page fault count of a task, as set in task->min_flt. */
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__u64 ac_minflt; /* Minor Page Fault Count */
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/* The major page fault count of a task, as set in task->maj_flt. */
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__u64 ac_majflt; /* Major Page Fault Count */
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2) Delay accounting fields::
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/* Delay accounting fields start
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*
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* All values, until the comment "Delay accounting fields end" are
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* available only if delay accounting is enabled, even though the last
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* few fields are not delays
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*
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* xxx_count is the number of delay values recorded
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* xxx_delay_total is the corresponding cumulative delay in nanoseconds
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*
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* xxx_delay_total wraps around to zero on overflow
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* xxx_count incremented regardless of overflow
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*/
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/* Delay waiting for cpu, while runnable
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* count, delay_total NOT updated atomically
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*/
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__u64 cpu_count;
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__u64 cpu_delay_total;
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/* Following four fields atomically updated using task->delays->lock */
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/* Delay waiting for synchronous block I/O to complete
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* does not account for delays in I/O submission
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*/
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__u64 blkio_count;
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__u64 blkio_delay_total;
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/* Delay waiting for page fault I/O (swap in only) */
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__u64 swapin_count;
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__u64 swapin_delay_total;
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/* cpu "wall-clock" running time
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* On some architectures, value will adjust for cpu time stolen
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* from the kernel in involuntary waits due to virtualization.
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* Value is cumulative, in nanoseconds, without a corresponding count
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* and wraps around to zero silently on overflow
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*/
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__u64 cpu_run_real_total;
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/* cpu "virtual" running time
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* Uses time intervals seen by the kernel i.e. no adjustment
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* for kernel's involuntary waits due to virtualization.
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* Value is cumulative, in nanoseconds, without a corresponding count
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* and wraps around to zero silently on overflow
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*/
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__u64 cpu_run_virtual_total;
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/* Delay accounting fields end */
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/* version 1 ends here */
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3) Extended accounting fields::
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/* Extended accounting fields start */
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/* Accumulated RSS usage in duration of a task, in MBytes-usecs.
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* The current rss usage is added to this counter every time
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* a tick is charged to a task's system time. So, at the end we
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* will have memory usage multiplied by system time. Thus an
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* average usage per system time unit can be calculated.
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*/
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__u64 coremem; /* accumulated RSS usage in MB-usec */
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/* Accumulated virtual memory usage in duration of a task.
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* Same as acct_rss_mem1 above except that we keep track of VM usage.
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*/
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__u64 virtmem; /* accumulated VM usage in MB-usec */
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/* High watermark of RSS usage in duration of a task, in KBytes. */
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__u64 hiwater_rss; /* High-watermark of RSS usage */
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/* High watermark of VM usage in duration of a task, in KBytes. */
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__u64 hiwater_vm; /* High-water virtual memory usage */
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/* The following four fields are I/O statistics of a task. */
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__u64 read_char; /* bytes read */
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__u64 write_char; /* bytes written */
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__u64 read_syscalls; /* read syscalls */
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__u64 write_syscalls; /* write syscalls */
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/* Extended accounting fields end */
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4) Per-task and per-thread statistics::
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__u64 nvcsw; /* Context voluntary switch counter */
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__u64 nivcsw; /* Context involuntary switch counter */
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5) Time accounting for SMT machines::
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__u64 ac_utimescaled; /* utime scaled on frequency etc */
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__u64 ac_stimescaled; /* stime scaled on frequency etc */
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__u64 cpu_scaled_run_real_total; /* scaled cpu_run_real_total */
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6) Extended delay accounting fields for memory reclaim::
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/* Delay waiting for memory reclaim */
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__u64 freepages_count;
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__u64 freepages_delay_total;
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::
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}
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