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

[Ravi Bangoria]

> We use the following command to track a process's memory footprint:
>   #perf record -e ibs_fetch// -e ibs_op// -p xxx --phys-addr -- sleep 10
> 
> In the mysql tests, I catched over 1,804,973 records for ibs_op event.
> I found that over 53% records(970,554) are like this:
>         ibs_op//:  ffffffffb6017739               0
> 
> The physical address is 0 for these records. These records are not needed
> by us, and they wasted the CPU cycles.
> 
> This patch adds an ibs_op/phy_addr_only term that discards samples
> without a valid physical address (dc_phy_addr_valid == 0) in the interrupt
> handler. And it avoids the phys_addr=0 noise when used with --phys-data.

Why not simply use the BPF filter?

  $ perf record -e ibs_op// --phys-data --filter 'phys_addr != 0' ...

Thanks,
Ravi