> From: Stephen Hemminger [mailto:step...@networkplumber.org] > Sent: Monday, 6 November 2023 20.24 > > On Mon, 2 Oct 2023 10:42:53 +0200 > Morten Brørup <m...@smartsharesystems.com> wrote: > > > > Switching to rte_pktmbuf_pool_create() still leaves the user with > the > > > possibility to shoot himself in the foot (I was thinking of setting > > > some --mbuf-pool-ops-name EAL option). > > > > > > This application has explicit requirements in terms of concurrent > > > access (and I don't think the mempool library exposes per driver > > > capabilities in that regard). > > > The application was enforcing the use of mempool/ring so far. > > > > > > I think it is safer to go with an explicit > > > rte_pktmbuf_pool_create_by_ops(... "ring_mp_mc"). > > > WDYT? > > > > <feature creep> > > Or perhaps one of "ring_mt_rts" or "ring_mt_hts", if any of those > mbuf pool drivers are specified on the command line; otherwise fall > back to "ring_mp_mc". > > > > Actually, I prefer Stephen's suggestion of using the default mbuf > pool driver. The option is there for a reason. > > > > However, David is right: We want to prevent the user from using a > thread-unsafe mempool driver in this use case. > > > > And I guess there might be other use cases than this one, where a > thread-safe mempool driver is required. So adding a generalized > function to get the "upgraded" (i.e. thread safe) variant of a mempool > driver would be nice. > > </feature creep> > > If the user overrides the default mbuf pool type, then it will need to > be thread safe for > the general case of driver as well (or they are on single cpu).
If they have chosen a thread safe pool type, using the chosen type will work for dumpcap too. I think we all agree on that. I'm not sure I understand your single-cpu argument, so let me try to paraphrase: If their application only uses one EAL thread, and they have chosen "ring_sc_sp", dumpcap also work, because mempool accesses are still single-threaded. Is this correctly understood? Or are you saying that if they want to use dumpcap, they must choose a thread safe pool type for their application (regardless if the application is single-threaded or not)? > > > I think the patch should be applied as is.
