> --- Sven Eschenberg <eschenb@xxxxxxxxxxxxxxxxxxx> > wrote: > >> Hi Ranjith, >> >> I might be wrong on this, but I think the question >> is, if the Operating >> System permits it or under which circumstances. It's >> neither a question >> of what gcc or the hardware does, but what the OS >> you are using allows >> to which processes. > Thanks. I am sending more details of my problem. > > The OS I am using : Linux. > The language in which the program is written : C(I am > attaching the program) > The compiler : gcc 3.2.3 > Processor : Pentium 4 > I know password for root login. I logged in as root > and compiled my program. When compiled no errors were > reported. But when I run the program it simply shows > "Segmentation fault". > > My goal is to measure performance parameters (for > example the number of branch instructions that were > mispredicted), on Pentium 4, using "RDMSR" and "WRMSR" > instructions. Also I want to disble interrupts while > running my program. > The problem is that those instructions can be run only > at privilege level zero. You should consider using Kernel mode linux (kernel recompilation needed) or write kernel module: kernel mode linux: http://web.yl.is.s.u-tokyo.ac.jp/~tosh/kml/ Arturas M.
