a question about process information

[tgh]

hi
        I have a question about linux , I hear that linux2.6.27 provide
information about resource usage for each process, such as, CPU, memory,
I/O, and I want to know how to get it, does some proc or sysfs have these
information ,or something else has it, or how to get it from systemtap
        Could you help me

Thank you