Hi, I'm using the function rdtscll(); located in asm/msr.h in my code. Today I tried to deploy the software to our grid-box running SL (Version 3) which is missing this particular file although timex.h refers to rdtscll() in the get_cycles-call and therefor always returns 0 (CONFIG_X86_TSC is not set). Is there a reason for not including msr.h? Is it included in V4 of SL? Kind regards, Thomas William