On 2020-07-14 22:51, Stephen Hemminger wrote: > On Tue, 14 Jul 2020 18:59:59 +0000 > Honnappa Nagarahalli <honnappa.nagaraha...@arm.com> wrote: > >> <snip> >> >>>> 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. >> This sounds similar to 'keep alive' functionality. >> >>>> 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 guess here you mean the OS provided thread ID. Are there OS calls that >> provide the CPU runtime? > This might be difficult sinc thread id in Linux/glibc is intentionally and > opaque value. > According to Posix the only valid way to look at it is to use return value > from > pthread_create() and pthread_self(). >
The rte_lcore_thread_id() would return this value, which could subsequently be used in the application, calling pthread_getcpuclockid() and clock_gettime() to retrieve the run time for the lcore worker thread. No need to break the opacity in this case, although the Linux thread id (i.e. the result of a gettid()) would be useful in case you would want to dig around in /proc for other scheduler statistics. Regards, Mattias
