Re: [PATCH] perf/amd/ibs: add phy_addr_only software filter for ibs_op

[Huang Shijie]

Hi Ravi,

Thanks for taking a look.

> Why not simply use the BPF filter?
>   $ perf record -e ibs_op// --phys-data --filter 'phys_addr != 0' ...

I did try the BPF filter.

Measurements below are system-wide ibs_op sampling for 5s on a
384-CPU Hygon box under a 400-thread sysbench oltp_read_only load
at three sampling periods:

    -c     filter        valid samples    
  ------  ------------  ---------- 
  100000  phy_addr_only  19,345,907 
  100000  BPF filter     17,939,819 

   30000  phy_addr_only  54,670,617 
   30000  BPF filter     47,926,784 

   10000  phy_addr_only  61,606,488 
   10000  BPF filter     40,826,086 


The phy_addr_only produces more *valid* samples than the BPF filter.

Thanks,
Huang Shijie