La commande 'bosdebug' permet d'activer ou de désactiver les options de debugging du système.
La surveillance mémoire s'active à l'aide de la commande suivante :
# bosdebug -M
Memory debugger on
Memory sizes 0
Network memory sizes 0
Kernel debugger off
Real Time Kernel off
Backtracking fault log on
Kernext Memory Tracking off
A la suite de cette commande, l'image de boot doit être re-générée :
# bosboot -a
A previous bosdebug command has changed characteristics of this
boot image. Use bosdebug -L to display what these changes are.
bosboot: Boot image is 51228 512 byte blocks.
# bosdebug -L
Memory debugger on
Memory sizes 0
Network memory sizes 0
Kernel debugger off
Real Time Kernel off
Backtracking fault log on
Kernext Memory Tracking off
Pour la prise en compte, un reboot est nécessaire :
# shutdown -Fr
Ci-dessous la documentation officielle
bosdebug Command
Purpose
Enables, disables, and/or displays the status of debugging features of the system.
Syntax
bosdebug [-b] [-D | -I] [-K on | off] [-M] [-n sizelist] [-R on | off] [-M] [-s sizelist | -S]
bosdebug [-h]
bosdebug [-L]
bosdebug [-o]
Description
The bosdebug command enables, disables, and/or displays the status of debugging features of the system.
| Item | Description |
|---|---|
| -b | Disables data collection of state information for backtracking faults. This information is useful for debugging certain kinds of kernel errors. Disabling state information data collection for backtracking faults can provide a slight performance improvement under certain rare workloads, but that disablement does not allow the preservation of data that might be critical for problem analysis. |
| -D | Causes the kernel debug program to be loaded on each subsequent reboot. |
| -I | Causes the kernel debug program to be loaded and invoked on each subsequent reboot. |
| -L | Displays the current settings for the kernel debug program and the memory overlay detection system. Note that the settings shown will not take effect until after the next time that the bosboot -a and shutdown -rcommands are run. This is the default. |
| -K on | off | Sets the state of kernel extension allocation tracking. |
| -o | Turns off all debugging features of the system. |
| -R on | off | Activates or deactivates the real-time kernel option. When -R on is specified, the kernel proactively generates an extra interrupt to ensure rapid response to a cross-CPU preemption request when the preempting thread is considered a real-time thread. Without this extra interrupt (called an MPC), the preempted thread might continue to run uninterrupted until the next regularly scheduled timer tick, or generally up to 10 ms.
Threads running with a fixed priority policy are considered real time by default. If RT_MPC=ON is exported in the environment before a process is started, that process's threads are also considered real time. Note that while the extra MPC interrupts reduce preemption latency, they also add overhead. Consider this additional overhead before exporting RT_MPC=ON in the default environment. |
| -l <file> | Loads a symbol file into kernel for the kdb debugger print facility. Loads the symbols immediately. Do not reboot. A symbol file to print LFS structures may be created as follows:
|
| -f | Flushes all the symbols (loaded through -l option) from kernel memory. Flushed immediately. Does not require a reboot. |
| -M | Causes the memory overlay detection system to be enabled. Memory overlays in kernel extensions and device drivers will cause a system crash. |
| -s sizelist | Causes the memory overlay detection system to promote each of the specified allocation sizes to a full page, and allocate and hide the next subsequent page after each allocation. This causes references beyond the end of the allocated memory to cause a system crash. sizelist is a list of memory sizes separated by commas. Each size must be in the range from 16 to 2048, and must be a power of 2. |
| -S | Causes the memory overlay detection system to promote all allocation sizes to the next higher multiple of page size (4096), but does not hide subsequent pages. This improves the chances that references to freed memory will result in a crash, but it does not detect reads or writes beyond the end of allocated memory until that memory is freed. |
| -n sizelist | Has the same effect as the -s option, but works instead for network memory. Each size must be in the range from 32 to 2048, and must be a power of 2. This causes the net_malloc_frag_mask variable of the nocommand to be turned on during boot. |
| -h | Displays the usage message for this command. |
Any changes made by this command will not take effect until the bosboot and shutdown -r commands have been run (except -l and -foptions).
Security
Attention RBAC users and Trusted AIX® users: This command can perform privileged operations. Only privileged users can run privileged operations. For more information about authorizations and privileges, see Privileged Command Database in Security. For a list of privileges and the authorizations associated with this command, see the lssecattr command or the getcmdattr subcommand.
