Re: [dpdk-dev] Retrieving lcore worker thread id

["Mattias Rönnblom" <mattias.ronnblom@ericsson.com>]

On 2020-07-14 15:08, Van Haaren, Harry wrote:
>> -----Original Message-----
>> From: dev <dev-bounces@dpdk.org> On Behalf Of Mattias Rönnblom
>> Sent: Tuesday, July 14, 2020 1:04 PM
>> To: dpdk-dev <dev@dpdk.org>
>> Cc: Tomasz Piatkowski <tomasz.piatkowski@ericsson.com>
>> Subject: [dpdk-dev] Retrieving lcore worker thread id
>>
>> Hi.
> Hey,
>
>> In DPDK 19.11, the lcore_config struct of <rte_lcore.h> is made private,
>> and with it the possibility to look up the thread id of the lcore worker
>> threads disappears.
>>
>> One use case is an application with a monitoring function (on some
>> control plane thread), which uses the thread ids to make sure the worker
>> threads gets the CPU runtime they should, and thus is able to detect
>> stalls.
>>
>> Is there some other way of finding out the thread_id of a lcore worker
>> thread? All I can think of are hacks like using a temporary service
>> function for service cores, in combination with requiring launched
>> application threads also to store their thread id in some global
>> structure (index by lcore_id).
> -1 for the service cores idea. I like the creative solution thinking,
> but not as a long-term solution.
>
>> Is there some cleaner way? If not, would adding something like a
>> rte_lcore_thread_id() function make sense?
> I think given your use-case description above, this makes sense.
> I guess it comes down to a discussion around if thread_id should
> be exposed at all - but given you have a use I'd argue yes it should.
> Doing so in a cross-platform way might be a bit tricky though.
>

With the Windows port ongoing, I guess that's a valid concern. 
<rte_lcore.h> already is a heavy user of pthread ids though. Maybe you 
would leave that change to a later patch, which would typedef the whole 
thing into something DPDK specific and portable.


Regards,

     Mattias