On Tue, Aug 29, 2017 at 05:05:15PM +0530, Madhavan Srinivasan wrote: > > > On Tuesday 29 August 2017 06:22 AM, [email protected] wrote: > > From: Kan Liang <[email protected]> > > > > For understanding how the workload maps to memory channels and hardware > > behavior, it's very important to collect address maps with physical > > addresses. For example, 3D XPoint access can only be found by filtering > > the physical address. > > > > Add a new sample type for physical address. > > > > perf already has a facility to collect data virtual address. This patch > > introduces a function to convert the virtual address to physical address. > > The function is quite generic and can be extended to any architecture as > > long as a virtual address is provided. > > - For kernel direct mapping addresses, virt_to_phys is used to convert > > the virtual addresses to physical address. > > - For user virtual addresses, __get_user_pages_fast is used to walk the > > pages tables for user physical address. > > - This does not work for vmalloc addresses right now. These are not > > resolved, but code to do that could be added. > > > > The new sample type requires collecting the virtual address. The > > virtual address will not be output unless SAMPLE_ADDR is applied. > > > > For security, the physical address can only be exposed to root or > > privileged user. > > Tested-by: Madhavan Srinivasan <[email protected]>
Thanks maddy!
