Re: [PATCH v2 1/2] eal: expose lcore pthread id

[Michael Pfeiffer <michael.pfeiffer@tu-ilmenau.de>]

On Thu, 2022-10-20 at 08:36 -0700, Stephen Hemminger wrote:
> On Thu, 20 Oct 2022 13:20:40 +0200
> David Marchand <david.marchand@redhat.com> wrote:
> 
> > On Fri, Oct 14, 2022 at 9:54 AM Markus Theil <markus.theil@tu-ilmenau.de>
> > wrote:
> > > 
> > > From: Michael Pfeiffer <michael.pfeiffer@tu-ilmenau.de>
> > > 
> > > Also expose the pthread id of each lcore, in
> > > order to allow modification of pthread attributes,
> > > for example use rte_thread_setname without executing
> > > pthread_self() on the maybe already running lcore.
> > > 
> > > The rte_lcore_to_thread_id function is added to API.
> > > 
> > > Signed-off-by: Michael Pfeiffer <michael.pfeiffer@tu-ilmenau.de>  
> > 
> > We are trying to abstract the use of pthread in DPDK API.
> > So I don't think this patch is going in the right direction.
> 
> Agree, exposing this will make Windows support harder
> and who knows what next OS to come will need.

Hi,
thanks for your feedback. I understand your concerns regarding abstraction and
portability.

Markus and I ultimately use the function in the patch to call
rte_thread_setname() (which takes the pthread id as an argument) to rename our
lcore workers from "lcore-worker-X" to something more meaningful in the scope
of our application. Having descriptive thread names makes debugging
significantly easier. For example, verifying CPU pinning worked as intended
with ps -T ..., or identifying threads in the Intel VTune profiler.

Would you consider something like
- int rte_lcore_setname(unsigned int lcore_id, const char *name)
- int rte_lcore_getname(unsigned int lcore_id, char *name, size_t len)
a more appropriate API? That would still allow us to set names from the main
lcore, but would not expose any pthread internals.

Thanks & regards
Michael