Re: [PATCH 0/2] perf: add new uncore command

[Ingo Molnar <mingo@kernel.org>]

* Stephane Eranian <eranian@google.com> wrote:

> This patchset adds a new command to perf: perf uncore.
> It is used to measure processor socket-level metrics
> on a system-wide basis and at all priv levels.
> 
> The command comes with a set of predefined key metrics
> which are useful to measure multi-socket system imbalance
> and various bandwidths.
> 
> The following metrics are currently defined:
>   - memory bandwidth (Nehalem, Westmere, SandyBridge-EP)
>   - PCIe bandwidth (SandyBridge-EP)
>   - QPI bandwidth (SandyBridge-EP)
>   - C-state residency (SandyBridge-EP)
> 
> Others can be added in the future.
> 
> The command provides options to modify the unit of the metrics
> (default: MB/s for bandwidth).
> 
> Example on Nehalem:
> 
>  # perf uncore
>  #------------------------------
>  #           Socket0           |
>  #------------------------------
>  #        RAM Bandwidth        |
>  #            Wr             Rd|
>  #          MB/s           MB/s|
>  #------------------------------
>          4954.99       14897.29
>          4953.97       14894.56
>          4947.52       14874.97
> 
> To make plotting easier, the output can be augmented with a timestamp:
> 
>  # perf uncore -T
>  #----------------------------------------
>  #         |           Socket0           |
>  #         |------------------------------
>  #   Time  |        RAM Bandwidth        |
>  #    in   |            Wr             Rd|
>  #   secs  |          MB/s           MB/s|
>  #----------------------------------------
>           1        4952.50       14890.49
>           2        4955.55       14900.19
>           3        4949.13       14879.60
>           4        4954.66       14896.26

Looks really useful - how about naming it in a bit more generic 
way, because I'm quite sure this command will become popular and 
'perf uncore' is a bit un-intutive.

A couple of possibilities:

  perf system
  perf hw
  perf hw-stat

and also adding subcommands instead of options for the various 
views/metrics, such as:

  perf hw ram
  perf hw pci
  perf hw qpi
  perf hw cstate
  etc.

A plain 'perf hw' command would then list the available 
sub-commands and inform the user about the (current) set of 
hw subsystems that provide metrics.

Hm?

Thanks,

	Ingo