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()
