cross-instrumentation building kernel modules from SystemTap scripts cross-instrumentation generating instrumentation from SystemTap scripts cross-compiling script from here: http://sources.redhat.com/ml/systemtap/2008-q3/msg00310.html kernel modules from SystemTap scripts, building building kernel modules from SystemTap scripts instrumentation modules from SystemTap scripts, building building instrumentation modules from SystemTap scripts compiling instrumentation/kernel modules from SystemTap scripts cross-compiling above; add short description, significance, howto, script (test first) When users run a SystemTap script, SystemTap builds a kernel module out of that script. SystemTap then loads the module into the kernel, allowing it to extract the specified data directly from the kernel (refer to in for more information). Normally, however, SystemTap scripts can only be run on systems where SystemTap is deployed (as in ). This could mean that if you want to run SystemTap on ten systems, you would need to deploy SystemTap on all those systems. In some cases, this may be neither feasible nor desired. For instance, corporate policy may prohibit an administrator from installing RPMs that provide compilers or debug information on specific machines, which will prevent the deployment of SystemTap. To work around this, you can resort to cross-instrumentation. Cross-instrumentation is the process of generating SystemTap instrumentation module from a SystemTap script on one computer to be used on another computer. This process offers the following benefits: cross-instrumentation advantages of advantages of cross-instrumentation The kernel information packages for various machines can be installed on a single host machine. Each target machine only needs one RPM to installed to use the generated SystemTap instrumentation module: systemtap-runtime. For the sake of simplicity, we will be using the following terms throughout this section: cross-instrumentation instrumentation module instrumentation module cross-instrumentation instrumentation module — the kernel module built from a SystemTap script; i.e. the SystemTap module is built on the host system, and will be loaded on the target kernel of target system. cross-instrumentation host system host system cross-instrumentation host system — the system on which you compile the instrumentation modules (from SystemTap scripts), to be loaded on target systems. cross-instrumentation target system target system cross-instrumentation target system — the system for which you are building the instrumentation module (from SystemTap scripts). cross-instrumentation target kernel target kernel cross-instrumentation target kernel — the kernel of the target system. This is the kernel on which you wish to load/run the instrumentation module. cross-instrumentation configuration host system and target system host system and target system cross-instrumentation configuration target system and host system configuration Install the systemtap-runtime RPM on each target system. Determine the kernel running on each target system by running uname -r on each target system. Install SystemTap on the host system. You will be building the instrumentation module for the target systems on the host system. For instructions on how to install SystemTap, refer to . Using the target kernel version determined earlier, install the target kernel and related RPMs on the host system by the method described in . If multiple target systems use different target kernels, you will need to repeat this step for each different kernel used on the target systems. After performing , you can now build the instrumentation module (for any target system) on the host system. To build the instrumentation module, run the following command on the host system (be sure to specify the appropriate values): stap -r kernel_version script -m module_name Here, kernel_version refers to the version of the target kernel (the output of uname -r on the target machine), script refers to the script to be converted into an instrumentation module, and module_name is the desired name of the instrumentation module. uname -m determining architecture notation architecture notation, determining To determine the architecture notation of a running kernel, run uname -m. Once the the instrumentation module is compiled, copy it to the target system and then load it using: staprun module_name.ko For example, to create the instrumentation module simple.ko from a SystemTap script named simple.stp for the target kernel 2.6.18-92.1.10.el5 (on x86_64 architecture), use the following command: stap -r 2.6.18-92.1.10.el5 -e 'probe vfs.read {exit()}' -m simple This will create a module named simple.ko. To use the instrumentation module simple.ko, copy it to the target system and run the following command (on the target system): staprun simple.ko The host system must be the same architecture and running the same distribution of Linux as the target system in order for the built instrumentation module to work.