Taskset is used to set or retrieve the CPU affinity of a running process given its PID or to launch a new COMMAND with a given CPU affinity. Under latest version of Debian / Ubuntu / Redhat Linux taskset is installed by default with util-linux package.

Xaprb.com shows a nice example on how to print I/O operations per-process by iopp here. This command is only available in kernel-2.6.20+ or equivalent patched, so they don’t work for older linux systems (including RHEL4, 5.0, 5.1, 5.2).

You can use chrt command to set or retrieve the real-time scheduling attributes / scheduling priority of an existing PID. From its man page: The scheduler is the kernel part that decides which runnable process will be executed by the CPU next. The Linux scheduler offers three different scheduling [...]

I’ll show two tips here on how to check a process’ running time, it’s very helpful for system administrators to know these tips as they may need to clean some abnormal processes. It’s a common issue when using FastCGI with apache.