Buscar

Este contenido no está disponible en el idioma seleccionado.

4.2.4. I/O Monitoring (By Device)

download PDF
This section describes how to monitor I/O activity on a specific device.
traceio2.stp

#! /usr/bin/env stap

global device_of_interest

probe begin {
  /* The following is not the most efficient way to do this.
      One could directly put the result of usrdev2kerndev()
      into device_of_interest.  However, want to test out
      the other device functions */
  dev = usrdev2kerndev($1)
  device_of_interest = MKDEV(MAJOR(dev), MINOR(dev))
}

probe vfs.write, vfs.read
{
  if (dev == device_of_interest)
    printf ("%s(%d) %s 0x%x\n",
            execname(), pid(), probefunc(), dev)
}

traceio2.stp takes 1 argument: the whole device number. To get this number, use stat -c "0x%D" directory, where directory is located in the device you wish to monitor.
The usrdev2kerndev() function converts the whole device number into the format understood by the kernel. The output produced by usrdev2kerndev() is used in conjunction with the MKDEV(), MINOR(), and MAJOR() functions to determine the major and minor numbers of a specific device.
The output of traceio2.stp includes the name and ID of any process performing a read/write, the function it is performing (that is vfs_read or vfs_write), and the kernel device number.
The following example is an excerpt from the full output of stap traceio2.stp 0x805, where 0x805 is the whole device number of /home. /home resides in /dev/sda5, which is the device we wish to monitor.

Example 4.8. traceio2.stp Sample Output

[...]
synergyc(3722) vfs_read 0x800005
synergyc(3722) vfs_read 0x800005
cupsd(2889) vfs_write 0x800005
cupsd(2889) vfs_write 0x800005
cupsd(2889) vfs_write 0x800005
[...]
Red Hat logoGithubRedditYoutubeTwitter

Aprender

Pruebe, compre y venda

Comunidades

Acerca de la documentación de Red Hat

Ayudamos a los usuarios de Red Hat a innovar y alcanzar sus objetivos con nuestros productos y servicios con contenido en el que pueden confiar.

Hacer que el código abierto sea más inclusivo

Red Hat se compromete a reemplazar el lenguaje problemático en nuestro código, documentación y propiedades web. Para más detalles, consulte el Blog de Red Hat.

Acerca de Red Hat

Ofrecemos soluciones reforzadas que facilitan a las empresas trabajar en plataformas y entornos, desde el centro de datos central hasta el perímetro de la red.

© 2024 Red Hat, Inc.