how to trace the behavior of different components of a computer by GEM5

Recently, I am trying to get the memory access trace from some benchmarks runing on GEM5. By reading the references http://www.m5sim.org/Main_Page, I got it done.

Below is an example:

1)scons build/X86_MESI_CMP_directory/gem5.opt  PROTOCOL=MESI_CMP_directory RUBY=true

2) ./build/X86_MESI_CMP_directory/gem5.opt --debug-flags=RubyMemory --trace-file rubymemory130704 configs/example/ruby_fs.py --kernel=/home/starking/fullsystem/m5_system_2.0b3/binaries/x86_64-vmlinux-2.6.28.4-smp  --disk-image=/home/starking/fullsystem/m5_system_2.0b3/disks/x86root-parsec.img 
--mem-size=1024MB --ruby

the point is --debug-flag , the choices to select could be displayed by the command:
./build/X86_MESI_CMP_directory/gem5.opt --debug-help
For just the memory access traces are what I want, so in the example above I chose --debug-flags=RubyMemory