[PATCH] usertools: enhance CPU layout

[Thomas Monjalon]

21/04/2023 03:47, Lu, Wenzhuo:
> Hi Stephen,
> 
> From: Stephen Hemminger <stephen at networkplumber.org>
> > On Tue, 18 Apr 2023 13:25:41 +0800
> > Wenzhuo Lu <wenzhuo.lu at intel.com> wrote:
> > 
> > > The cores in a single CPU may be not all the same.
> > > The user tool is updated to show the
> > > difference of the cores.
> > >
> > > This patch addes below informantion,
> > > 1, Group the cores based on the die.
> > > 2, A core is either a performance core or an
> > >    efficency core.
> > >    A performance core is shown as 'Core-P'.
> > >    An efficency core is shown as 'Core-E'.
> > > 3, All the E-cores which share the same L2-cache
> > >    are grouped to one module.
> > >
> > > The known limitation.
> > > 1, To tell a core is P-core or E-core is based on if
> > >    this core shares L2 cache with others.
> > >
> > > Signed-off-by: Wenzhuo Lu <wenzhuo.lu at intel.com>
> > 
> > Side note:
> > This tool only exists because of lack of simple tool at the time.
> > Looking around, found that there is a tool 'lstopo' under the hwloc package
> > that gives output in many formats including graphical and seems to do a better
> > job than the DPDK python script.

lstopo existed already when introducing this python script.
See its home page: https://www.open-mpi.org/projects/hwloc/

We talked about dropping the DPDK script in the past:
http://inbox.dpdk.org/dev/20151127161008.GA27472@bricha3-MOBL3/

I recommend using "lstopo-no-graphics --merge"

> > Not sure how much farther DPDK should go in this area?
> > Really should be a distro tool.
> 
> Many thanks for your review and comments.
> Have to say I'm a green hand in this field. Just imitate the existing code to write mine. So, still trying to understand and handle the comments :)
> 
> Better to understand more about our opinion of this script before send a v2 patch.
> I've used 'lstopo'. It's a great tool.
> To my opinion, considering there're Linux tools to show all kinds of information, the reason that DPDK has its own tool is to summarize and emphasize the information that is important to DPDK. Here it's that some cores are more powerful than others. When the users use a testpmd-like APP, they can choose the appropriate cores after DPDK reminds them about the difference between cores.
> Add Thomas for more suggestions. Thanks.

Adding Brice, hwloc maintainer.

I think it would be better to contribute to the hwloc project.
If we need a different set of info, we can probably tune it with options.