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Programming/Linux_Kernel

/Proc/[pid]/stat 에서 보이는 정보 분석하기

출력되는 정보를 다음과 같은 순서로 해석하면 된다.

FLDNUM FMT  ARG                      OUTPUT
      1 %d   task->pid                18173
      2 (%s) task->comm               (run-mozilla.sh)
      3 %c   state                    S
      4 %d   ppid                     932
      5 %d   task->pgrp               18173
      6 %d   task->session            904
      7 %d   tty_nr                   0
      8 %d   tty_pgrp                 -1
      9 %lu  task->flags              0
     10 %lu  task->min_flt            186
     11 %lu  task->cmin_flt           118
     12 %lu  task->maj_flt            483
     13 %lu  task->cmaj_flt           470
     14 %lu  task->times.tms_utime    0
     15 %lu  task->times.tms_stime    0
     16 %ld  task->times.tms_cutime   0
     17 %ld  task->times.tms_cstime   0
     18 %ld  priority                 16
     19 %ld  nice                     0
     20 %ld  0UL /* removed */        0
     21 %ld  task->it_real_value      0
     22 %lu  task->start_time         4755372
     23 %lu  vsize                    2338816
     24 %ld  mm ? mm->rss : 0 /* you might want to shift this left 3 */ 220
     25 %lu  task->rlim[RLIMIT_RSS].rlim_cur 4294967295
     26 %lu  mm ? mm->start_code : 0  134512640
     27 %lu  mm ? mm->end_code : 0    135029780
     28 %lu  mm ? mm->start_stack : 0 3221224048
     29 %lu  esp                      3221222148
     30 %lu  eip                      1108035433
     31 %lu  task->pending.signal.sig[0] & 0x7fffffffUL 0
     32 %lu  task->blocked.sig[0] & 0x7fffffffUL 65536
     33 %lu  sigign.sig[0] & 0x7fffffffUL 4
     34 %lu  sigcatch.sig[0] & 0x7fffffffUL 65538
     35 %lu  wchan                    3222384609
     36 %lu  task->nswap              0
     37 %lu  task->cnswap             0
     38 %d   task->exit_signal        17
     39 %d   task->cpu

각 의미는 아래를 보자.
 /proc/[pid]/stat
              Status information about the process.  This is used by ps(1).
              It is defined in the kernel source file fs/proc/array.c.

              The fields, in order, with their proper scanf(3) format
              specifiers, are:

              (1) pid  %d
                        The process ID.

              (2) comm  %s
                        The filename of the executable, in parentheses.
                        This is visible whether or not the executable is
                        swapped out.

              (3) state  %c
                        One of the following characters, indicating process
                        state:

                        R  Running

                        S  Sleeping in an interruptible wait

                        D  Waiting in uninterruptible disk sleep

                        Z  Zombie

                        T  Stopped (on a signal) or (before Linux 2.6.33)
                           trace stopped

                        t  Tracing stop (Linux 2.6.33 onward)

                        W  Paging (only before Linux 2.6.0)

                        X  Dead (from Linux 2.6.0 onward)

                        x  Dead (Linux 2.6.33 to 3.13 only)

                        K  Wakekill (Linux 2.6.33 to 3.13 only)

                        W  Waking (Linux 2.6.33 to 3.13 only)

                        P  Parked (Linux 3.9 to 3.13 only)

              (4) ppid  %d
                        The PID of the parent of this process.

              (5) pgrp  %d
                        The process group ID of the process.

              (6) session  %d
                        The session ID of the process.

              (7) tty_nr  %d
                        The controlling terminal of the process.  (The minor
                        device number is contained in the combination of
                        bits 31 to 20 and 7 to 0; the major device number is
                        in bits 15 to 8.)

              (8) tpgid  %d
                        The ID of the foreground process group of the
                        controlling terminal of the process.

              (9) flags  %u
                        The kernel flags word of the process.  For bit
                        meanings, see the PF_* defines in the Linux kernel
                        source file include/linux/sched.h.  Details depend
                        on the kernel version.

                        The format for this field was %lu before Linux 2.6.

              (10) minflt  %lu
                        The number of minor faults the process has made
                        which have not required loading a memory page from
                        disk.

              (11) cminflt  %lu
                        The number of minor faults that the process's
                        waited-for children have made.

              (12) majflt  %lu
                        The number of major faults the process has made
                        which have required loading a memory page from disk.

              (13) cmajflt  %lu
                        The number of major faults that the process's
                        waited-for children have made.

              (14) utime  %lu
                        Amount of time that this process has been scheduled
                        in user mode, measured in clock ticks (divide by
                        sysconf(_SC_CLK_TCK)).  This includes guest time,
                        guest_time (time spent running a virtual CPU, see
                        below), so that applications that are not aware of
                        the guest time field do not lose that time from
                        their calculations.

              (15) stime  %lu
                        Amount of time that this process has been scheduled
                        in kernel mode, measured in clock ticks (divide by
                        sysconf(_SC_CLK_TCK)).

              (16) cutime  %ld
                        Amount of time that this process's waited-for
                        children have been scheduled in user mode, measured
                        in clock ticks (divide by sysconf(_SC_CLK_TCK)).
                        (See also times(2).)  This includes guest time,
                        cguest_time (time spent running a virtual CPU, see
                        below).

              (17) cstime  %ld
                        Amount of time that this process's waited-for
                        children have been scheduled in kernel mode,
                        measured in clock ticks (divide by
                        sysconf(_SC_CLK_TCK)).

              (18) priority  %ld
                        (Explanation for Linux 2.6) For processes running a
                        real-time scheduling policy (policy below; see
                        sched_setscheduler(2)), this is the negated
                        scheduling priority, minus one; that is, a number in
                        the range -2 to -100, corresponding to real-time
                        priorities 1 to 99.  For processes running under a
                        non-real-time scheduling policy, this is the raw
                        nice value (setpriority(2)) as represented in the
                        kernel.  The kernel stores nice values as numbers in
                        the range 0 (high) to 39 (low), corresponding to the
                        user-visible nice range of -20 to 19.

                        Before Linux 2.6, this was a scaled value based on
                        the scheduler weighting given to this process.

              (19) nice  %ld
                        The nice value (see setpriority(2)), a value in the
                        range 19 (low priority) to -20 (high priority).

              (20) num_threads  %ld
                        Number of threads in this process (since Linux 2.6).
                        Before kernel 2.6, this field was hard coded to 0 as
                        a placeholder for an earlier removed field.

              (21) itrealvalue  %ld
                        The time in jiffies before the next SIGALRM is sent
                        to the process due to an interval timer.  Since
                        kernel 2.6.17, this field is no longer maintained,
                        and is hard coded as 0.

              (22) starttime  %llu
                        The time the process started after system boot.  In
                        kernels before Linux 2.6, this value was expressed
                        in jiffies.  Since Linux 2.6, the value is expressed
                        in clock ticks (divide by sysconf(_SC_CLK_TCK)).

                        The format for this field was %lu before Linux 2.6.

              (23) vsize  %lu
                        Virtual memory size in bytes.

              (24) rss  %ld
                        Resident Set Size: number of pages the process has
                        in real memory.  This is just the pages which count
                        toward text, data, or stack space.  This does not
                        include pages which have not been demand-loaded in,
                        or which are swapped out.

              (25) rsslim  %lu
                        Current soft limit in bytes on the rss of the
                        process; see the description of RLIMIT_RSS in
                        getrlimit(2).

              (26) startcode  %lu
                        The address above which program text can run.

              (27) endcode  %lu
                        The address below which program text can run.

              (28) startstack  %lu
                        The address of the start (i.e., bottom) of the
                        stack.

              (29) kstkesp  %lu
                        The current value of ESP (stack pointer), as found
                        in the kernel stack page for the process.

              (30) kstkeip  %lu
                        The current EIP (instruction pointer).

              (31) signal  %lu
                        The bitmap of pending signals, displayed as a
                        decimal number.  Obsolete, because it does not
                        provide information on real-time signals; use
                        /proc/[pid]/status instead.

              (32) blocked  %lu
                        The bitmap of blocked signals, displayed as a
                        decimal number.  Obsolete, because it does not
                        provide information on real-time signals; use
                        /proc/[pid]/status instead.

              (33) sigignore  %lu
                        The bitmap of ignored signals, displayed as a
                        decimal number.  Obsolete, because it does not
                        provide information on real-time signals; use
                        /proc/[pid]/status instead.

              (34) sigcatch  %lu
                        The bitmap of caught signals, displayed as a decimal
                        number.  Obsolete, because it does not provide
                        information on real-time signals; use
                        /proc/[pid]/status instead.

              (35) wchan  %lu
                        This is the "channel" in which the process is
                        waiting.  It is the address of a location in the
                        kernel where the process is sleeping.  The
                        corresponding symbolic name can be found in
                        /proc/[pid]/wchan.

              (36) nswap  %lu
                        Number of pages swapped (not maintained).

              (37) cnswap  %lu
                        Cumulative nswap for child processes (not
                        maintained).

              (38) exit_signal  %d  (since Linux 2.1.22)
                        Signal to be sent to parent when we die.

              (39) processor  %d  (since Linux 2.2.8)
                        CPU number last executed on.

              (40) rt_priority  %u  (since Linux 2.5.19)
                        Real-time scheduling priority, a number in the range
                        1 to 99 for processes scheduled under a real-time
                        policy, or 0, for non-real-time processes (see
                        sched_setscheduler(2)).

              (41) policy  %u  (since Linux 2.5.19)
                        Scheduling policy (see sched_setscheduler(2)).
                        Decode using the SCHED_* constants in linux/sched.h.

                        The format for this field was %lu before Linux
                        2.6.22.

              (42) delayacct_blkio_ticks  %llu  (since Linux 2.6.18)
                        Aggregated block I/O delays, measured in clock ticks
                        (centiseconds).

              (43) guest_time  %lu  (since Linux 2.6.24)
                        Guest time of the process (time spent running a
                        virtual CPU for a guest operating system), measured
                        in clock ticks (divide by sysconf(_SC_CLK_TCK)).

              (44) cguest_time  %ld  (since Linux 2.6.24)
                        Guest time of the process's children, measured in
                        clock ticks (divide by sysconf(_SC_CLK_TCK)).

              (45) start_data  %lu  (since Linux 3.3)
                        Address above which program initialized and
                        uninitialized (BSS) data are placed.

              (46) end_data  %lu  (since Linux 3.3)
                        Address below which program initialized and
                        uninitialized (BSS) data are placed.

              (47) start_brk  %lu  (since Linux 3.3)
                        Address above which program heap can be expanded
                        with brk(2).

              (48) arg_start  %lu  (since Linux 3.5)
                        Address above which program command-line arguments
                        (argv) are placed.

              (49) arg_end  %lu  (since Linux 3.5)
                        Address below program command-line arguments (argv)
                        are placed.

              (50) env_start  %lu  (since Linux 3.5)
                        Address above which program environment is placed.

              (51) env_end  %lu  (since Linux 3.5)
                        Address below which program environment is placed.

              (52) exit_code  %d  (since Linux 3.5)
                        The thread's exit status in the form reported by
                        waitpid(2).


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