reference.texi

linux 操作系统下对系统资源监控程序的编写

@node Reference Manual, , White Paper, Top
@chapter LibGTop Reference Manual

@menu
* System Dependent::            System Dependent Functions.
* Common Functions::            Common Functions.
* Library Functions::           Library Functions.
@end menu

@node System Dependent, Common Functions, Reference Manual, Reference Manual
@section System Dependent Functions

@menu
* glibtop_cpu::                 CPU Usage.
* glibtop_mem::                 Memory Usage.
* glibtop_swap::                Swap Usage.
* glibtop_uptime::              System Uptime.
* glibtop_loadavg::             Load Average.
* glibtop_proclist::            Process List.
* glibtop_proc_state::          Process State.
* glibtop_proc_uid::            Process UID and TTY Information.
* glibtop_proc_mem::            Process Memory Information.
* glibtop_proc_time::           Process Time Information.
* glibtop_proc_signal::         Process Signal Information.
* glibtop_proc_kernel::         Process Kernel Data Information.
* glibtop_proc_segment::        Process Segment Information.
* glibtop_proc_args::           Process Arguments.
* glibtop_proc_map::            Process Memory Maps.
* glibtop_netload::             Network Load.
* glibtop_ppp::                 PPP Usage.
@end menu

@node glibtop_cpu, glibtop_mem, System Dependent, System Dependent
@subsection CPU Usage

Library function @code{glibtop_get_cpu}:

@example
@cartouche
void glibtop_get_cpu (glibtop_cpu *buf);
void glibtop_get_cpu_l (glibtop *server, glibtop_cpu *buf);
@end cartouche
@end example

Declaration of @code{glibtop_cpu} in @file{<glibtop/cpu.h>}:

@example
@cartouche
typedef struct _glibtop_cpu     glibtop_cpu;

struct _glibtop_cpu
@{
    guint64   flags,
        total,
        user,
        nice,
        sys,
        idle,
        frequency,
        xcpu_total [GLIBTOP_NCPU],
        xcpu_user [GLIBTOP_NCPU],
        xcpu_nice [GLIBTOP_NCPU],
        xcpu_sys  [GLIBTOP_NCPU],
@ifset LIBGTOP-1-1
        xcpu_idle [GLIBTOP_NCPU],
        xcpu_flags;
@end ifset
@ifclear LIBGTOP-1-1
        xcpu_idle [GLIBTOP_NCPU];
@end ifclear
@};
@end cartouche
@end example

All CPU units are measured in @dfn{jiffies} which are normally 1/100th of a
second (in which case @code{frequency} equals 100), but can also be in any
other unit. To get seconds, divide them by @code{frequency}.

@table @code
@item total
Number of clock ticks since system boot.

@item user
Number of clock ticks the system spent in user mode.

@item nice
Number of clock ticks the system spent in user mode (nice).

@item sys
Number of clock ticks the system spent in system mode.

@item idle
Number of clock ticks the system spent in the idle task.

@item frequency
Tick frequency (default is 100).

@end table

The @samp{xcpu_} values are for SMP systems - they are the same than
@code{total}, @code{user}, @code{nice}, @code{sys} and @code{idle}
except that they are arrays of @code{GLIBTOP_NCPU} (defined in
@file{<glibtop/limits.h>}) elements and contain one value for each CPU
in the system.

@ifset LIBGTOP-1-1
@table @code
@item xcpu_flags
This is interpreted as a bit-field: on systems like Solaris, not all CPUs
need to be running all the time, so we set the corresponding bit for each
CPU that is currently running.
@end table
@end ifset

Please note that all of the cpu values are absolute values measured in
certain units (to get seconds, divide them by @code{frequency}) since system
boot. To get percentual values, you need to call @code{glibtop_cpu}, save the
result, wait some time and then call it again and divide the differences of
the two values by the time you have waited.

@page
@node glibtop_mem, glibtop_swap, glibtop_cpu, System Dependent
@subsection Memory Usage

Library function @code{glibtop_get_mem}:

@example
@cartouche
void glibtop_get_mem (glibtop_mem *buf);
void glibtop_get_mem_l (glibtop *server, glibtop_mem *buf);
@end cartouche
@end example

Declaration of @code{glibtop_mem} in @file{<glibtop/mem.h>}:

@example
@cartouche
typedef struct _glibtop_mem     glibtop_mem;

struct _glibtop_mem
@{
    guint64   flags,
        total,
        used,
        free,
        shared,
        buffer,
        cached,
        user,
        locked;
@};
@end cartouche
@end example

Unless explicitly stated otherwise, all memory units are in bytes.

@table @code
@item total
Total physical memory.

@item used
Used memory size.

@item free
Free memory size.

@item shared
Shared memory size.

This are both segments that are @code{mmap()}ed with @code{MAP_SHARED} and
IPC Shared Memory segments.

@item buffer
Size of buffers.

@item cached
Size of cached memory.

@item user
Memory used from user processes.

This is normally @code{total - free - shared - buffer - cached}.

@item locked
Memory in locked segments.

@end table

@page
@node glibtop_swap, glibtop_uptime, glibtop_mem, System Dependent
@subsection Swap Usage

Library function @code{glibtop_get_swap}:

@example
@cartouche
void glibtop_get_swap (glibtop_swap *buf);
void glibtop_get_swap_l (glibtop *server, glibtop_swap *buf);
@end cartouche
@end example

Declaration of @code{glibtop_swap} in @file{<glibtop/swap.h>}:

@example
@cartouche
typedef struct _glibtop_swap    glibtop_swap;

struct _glibtop_swap
@{
    guint64   flags,
        total,
        used,
        free,
        pagein,
        pageout;
@};
@end cartouche
@end example

The following units are in bytes.

@table @code
@item total
Total swap space in the system.

@item used
Used swap space.

@item free
Free swap space.
@end table

You can use @code{pagein} and @code{pageout} to get some measure about how
much the system is swapping at the moment. They're increased each time a page
is swapped in or out, so you need to save this values, wait a little bit, get
them again and then compare the two results to find out how much the system
swapped in the meantime.

@table @code
@item pagein
Total number of swap pages that have been brought in since system boot

@item pageout
Total number of swap pages that have been brought out since system boot

@end table

@page
@node glibtop_uptime, glibtop_loadavg, glibtop_swap, System Dependent
@subsection Uptime

Library function @code{glibtop_get_uptime}:

@example
@cartouche
void glibtop_get_uptime (glibtop_uptime *buf);
void glibtop_get_uptime_l (glibtop *server, glibtop_uptime *buf);
@end cartouche
@end example

Declaration of @code{glibtop_uptime} in @file{<glibtop/uptime.h>}:

@example
@cartouche
typedef struct _glibtop_uptime  glibtop_uptime;

struct _glibtop_uptime
@{
    guint64 flags;
    double uptime,
        idletime;
    guint64 boot_time;
@};
@end cartouche
@end example

When porting LibGTop to a new system, you only need to implement @code{uptime}
and @code{idletime} if there's a faster or better way to obtain them as using
@code{glibtop_cpu} for it. Look at @file{sysdeps/freebsd/uptime.c} for an
example on how to obtain them using @code{glibtop_cpu}.

@table @code
@item uptime
Time in seconds since system boot.

@item idletime
Time in seconds the system spent in the idle task since system boot.
@end table

The following one was from a request on the @samp{linux-kernel} mailing list;
on a laptop with advanced power management @code{glibtop_cpu.total} may not
reflect the correct boot time of the system if the power was turned off by
means of APM in the meantime.

@table @code
@item boot_time
Time of last system boot in seconds since the epoch.
@end table

@page
@node glibtop_loadavg, glibtop_proclist, glibtop_uptime, System Dependent
@subsection Load Average

Library function @code{glibtop_get_loadavg}:

@example
@cartouche
void glibtop_get_loadavg (glibtop_loadavg *buf);
void glibtop_get_loadavg_l (glibtop *server, glibtop_loadavg *buf);
@end cartouche
@end example

Declaration of @code{glibtop_loadavg} in @file{<glibtop/loadavg.h>}:

@example
@cartouche
typedef struct _glibtop_loadavg glibtop_loadavg;

struct _glibtop_loadavg
@{
    guint64 flags;
    double loadavg [3];
    guint64 nr_running,
        nr_tasks,
        last_pid;
@};
@end cartouche
@end example

@table @code
@item loadavg

Number of jobs running simultaneously averaged over 1, 5 and 15 minutes.

@end table

The following fields are Linux specific and deprecated. You don't need to
implement them when porting LibGTop to a new system as they may be removed
in a future version.

@table @code
@item nr_running
Number of tasks currently running.

@item nr_tasks
Total number of tasks.

@item last_pid
Last PID.
@end table

@page
@node glibtop_proclist, glibtop_proc_state, glibtop_loadavg, System Dependent
@subsection Process List

Library function @code{glibtop_get_proclist}:

@example
@cartouche
unsigned *
glibtop_get_proclist (glibtop_proclist *buf,
                      int64_t which, int64_t arg);

unsigned *
glibtop_get_proclist_l (glibtop *server, glibtop_proclist *buf,
                        int64_t which, int64_t arg);
@end cartouche
@end example

Constants for the @code{which} argument:

@example
@cartouche
#define GLIBTOP_KERN_PROC_ALL           0
#define GLIBTOP_KERN_PROC_PID           1
#define GLIBTOP_KERN_PROC_PGRP          2
#define GLIBTOP_KERN_PROC_SESSION       3
#define GLIBTOP_KERN_PROC_TTY           4
#define GLIBTOP_KERN_PROC_UID           5
#define GLIBTOP_KERN_PROC_RUID          6

#define GLIBTOP_KERN_PROC_MASK          15

#define GLIBTOP_EXCLUDE_IDLE            0x1000
#define GLIBTOP_EXCLUDE_SYSTEM          0x2000
#define GLIBTOP_EXCLUDE_NOTTY           0x4000
@end cartouche
@end example

Declaration of @code{glibtop_proclist} in @file{<glibtop/proclist.h>}:

@example
@cartouche
typedef struct _glibtop_proclist        glibtop_proclist;

struct _glibtop_proclist
@{
    guint64   flags,
        number,
        total,
        size;
@};
@end cartouche
@end example

This function returns a list of all or a selected subset of all running
processes. You can use the @code{which} and @code{arg} arguments to
specify which processes should be returned.

You can use the following values for the @code{which} argument:

@table @code
@item GLIBTOP_KERN_PROC_ALL
Return information about all processes (the @code{arg} argument is ignored).

@item GLIBTOP_KERN_PROC_PID
Return information about all process with the pid @var{PID} which is passed
in @code{arg}. You can use this to find out whether some process still exists.

@item GLIBTOP_KERN_PROC_PGRP
Return all processes in process group @var{PGRP} which is passed in
@code{arg}.

@item GLIBTOP_KERN_PROC_SESSION
Return all processes in session @var{SESSION} which is passed in @code{arg}.

@item GLIBTOP_KERN_PROC_TTY
Return all processes which have the controlling tty @var{TTY} which is passed
in @code{arg} (@var{TTY} is interpreted as device number).

@item GLIBTOP_KERN_PROC_UID
Return all processes with effective uid @var{UID} which is passed in @code{arg}.

@item GLIBTOP_KERN_PROC_RUID
Return all processes with real uid @var{RUID} which is passed in @code{arg}.

@end table

You can alter the list of returned processes by using a binary OR of
@code{which} and the following constants:

@table @code
@item GLIBTOP_EXCLUDE_IDLE
Exclude idle processes.
@item GLIBTOP_EXCLUDE_SYSTEM
Exclude system processes.
@item GLIBTOP_EXCLUDE_NOTTY
Exclude processes without a controlling terminal.
@end table

The return value of @code{glibtop_get_proclist} is either @code{NULL} on
error or a @code{unsigned *} list of pids. Additionally, the following fields