On 2020-07-15 18:21, Stephen Hemminger wrote: > On Wed, 15 Jul 2020 10:17:09 +0000 > Mattias Rönnblom <mattias.ronnb...@ericsson.com> wrote: > >> 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 >> > The issue is glibc doesn't want to allow gettid() > there is no wrapper, the only way to get it is using syscall()
There was certainly a lot of reluctance to add it, but since glibc 2.30, there is a syscall wrapper in place.
