absolute debugger

[Satish Y]

Hi All,

Can anyone please explain me about adb(absolute debugger) program. I have gone through man pages, it was not clear.
I came to know from one of my friend that it can be used to find out information about memory, CPU and I/O too. How to find these parameters?...
What else we can find out with adb?....
Thanks in advance.

Regards,
Satish.

[Vincenzo Restuccia]

For memory:
echo "physmem/D" | adb /stand/vmunix /dev/kmem | tail -1 | awk '$2 > 0 {print $2 / 256 , "MByte" }'`


adb /stand/vmunix /dev/kmem | tail -1 | awk '{print $2}'`

[Joseph A Benaiah_1]

Satish,

In addition to finding out the parameters about the current kernel loaded into memory, you can also change kernel parameters 'on the fly' without rebooting your server.

For example, I had switch on SCSI reservation on a server doing a backup to a tape silo in an FC-AL environment but there was a conflict that was causing the mk_kernel program to fail. Temporaily, I got around it my modifying the parameter using adb as follows:

1. cp -p /stand/vmunix /stand/vmunix.safe

2. adb -w /stand/vmunix /dev/kmem
st_ats_enabled/W 1
st_ats_enabled?W 1
CTRL-D

Please note that changing kernel parameters should always done through SAM as SAM validates them. Changing parameters 'on the fly' is not usually HP's preferred method and could leave the system inoperable. In the above example I had no choice and I had tested this on a test server.

Cheers,

Joseph.

[Carlos Fernandez Riera · Accepted solution]

As long you run absolute debugger you can modify all what you want in memory. So the syntax is not very easy ( almost better).

As Joseph said, ypou can touch oyur kernel onthefly ... but you can so your server become unoperable...

IN the other hand you can see: http://forums.itrc.hp.com/cm/QuestionAnswer/1,1150,0xacb1e7613948d5118fef0090279cd0f9,00.html

[Sundararajan Anandhan_1]

Satish,

Adb is very usefull , though it should be used with caution.

To get a dump of kernel parameters..

echo '$e' | adb -k /stand/vmunix /dev/kmem > kernel.out

Look for itic_per_second in kernel.out
itic_per_second ---> convert into decimal ---> divide by 10,000 === to get the processor speed.

echo "phys_mem_pages/D" |
adb64 -k /stand/vmunix /dev/mem

phys_mem_pages:
phys_mem_pages: 523648

Remember use adb64 only if your OS is 64 bit, else , use adb.

Regards,
Sundar.