Update README.

Document use of sysfs for gfx arch lookup.

Change-Id: Ic326769be3e23d627e16fb1aae56c0d16ce99d78


[ROCm/rocminfo commit: b83efe00a4]

projects/rocminfo/README.md

@@ -31,13 +31,14 @@ rocm_agent_enumerator, will be in the build folder.
 
 "rocminfo" gives information about the HSA system attributes and agents.
 
-"rocm_agent_enumerator" prints the list of available AMD GCN ISA or architecture names. With the option '-name', it prints out available architectures names obtained from rocminfo. Otherwise, it generates ISA in one of four different ways:
+"rocm_agent_enumerator" prints the list of available AMD GCN ISA or architecture names. With the option '-name', it prints out available architectures names obtained from rocminfo. Otherwise, it generates ISA in one of five different ways:
 
 1. ROCM_TARGET_LST : a user defined environment variable, set to the path and filename where to find the "target.lst" file. This can be used in an install environment with sandbox, where execution of "rocminfo" is not possible.
 
 2. target.lst : user-supplied text file, in the same folder as "rocm_agent_enumerator". This is used in a container setting where ROCm stack may usually not available.
 
-3. rocminfo : a tool shipped with this script to enumerate GPU agents available on a working ROCm stack.
+3. HSA topology : gathers the information from the HSA node topology in /sys/class/kfd/kfd/topology/nodes/
 
 4. lspci : enumerate PCI bus and locate supported devices from a hard-coded lookup table.
 
+5. rocminfo : a tool shipped with this script to enumerate GPU agents available on a working ROCm stack.