Saturday, April 25, 2009

systemtap on 2009.1

Today I decided to have a play with systemtap and see if it worked on 2009.1, since it’s quite a need tool that Fedora has had for some time.  Luckly enough, it looked like the was an RPM available for it, so installed it and gave it a go..  no such luck.  The rpm is old and builds c code that won’t compile against the current kernel.  The way systemtap works, is it takes a system tap script  and compiles this script into C, It then compiles the C against the current kernel to build a kernel module, which is then loaded into the running kernel.

Not to be deterred by an out of date package (bug logged), I downloaded systemtap 0.9 from and compiled it.   (required: lib64elfutils-static-devel, gcc-c++).   It  requires quite a lot of the kernel files, so installed kernel-server-debug, kernel-server-devel.

After that, it worked pretty well,  I downloaded a few of the examples, like nettop.stp, which will output a nice top of network traffic by process. for example:

# stap nettop.stp
10219  500 eth0        101      67      19      73 firefox
0        0 eth0         55      92       3      46 swapper
2863     0 eth0         27      28       1      26 X
3583   500 eth0         13       4       5       0 sshd
3582    76 eth0          7       2       2       0 sshd
2913     0 eth0          4       4       0       0 python
2996     0 eth0          2       2       0       0 nmbd
4205   500 eth0          1       1       0       0 net_applet

Friday, April 03, 2009

How to prevent graphical grub menu on startup

I just discovered by accident, that holding down left shift during mandriva bootup from install cd prevents the graphical boot loader from starting.  It also provides debugging output for grub if you are booting from HDD.

I wish I knew this awhile ago, as it would have helped with installing Mandriva as a guest inside KVM where the graphical grub menu would always kill the virtual machine.