Thanks Dave, Neale. This is great information.
On Mon, Apr 6, 2020 at 6:14 AM Neale Ranns (nranns) <nra...@cisco.com> wrote: > > > In the test harness you can inject onto a given worker, e.g. see > IpsecTun6HandoffTests. > > > > /neale > > > > *From: *<vpp-dev@lists.fd.io> on behalf of Paul Vinciguerra < > pvi...@vinciconsulting.com> > *Date: *Sunday 5 April 2020 at 17:24 > *To: *"Dave Barach (dbarach)" <dbar...@cisco.com> > *Cc: *Elias Rudberg <elias.rudb...@bahnhof.net>, "vpp-dev@lists.fd.io" < > vpp-dev@lists.fd.io> > *Subject: *Re: [vpp-dev] VPP nat ipfix logging problem, need to use > thread-specific vlib_main_t? > > > > How can we test scenarios like this? > > 'set interface rx-placement' doesn't support pg interfaces. > > DBGvpp# set interface rx-placement TenGigabitEthernet5/0/0 worker 2 > DBGvpp# set interface rx-placement pg0 worker 2 > set interface rx-placement: not found > > DBGvpp# > > Is there another command to bind a pg interface to a worker thread? > > > > On Sun, Apr 5, 2020 at 8:08 AM Dave Barach via lists.fd.io <dbarach= > cisco....@lists.fd.io> wrote: > > If you have the thread index handy, that's OK. Otherwise, use > vlib_get_main() which grabs the thread index from thread local storage. > > -----Original Message----- > From: vpp-dev@lists.fd.io <vpp-dev@lists.fd.io> On Behalf Of Elias Rudberg > Sent: Sunday, April 5, 2020 4:58 AM > To: vpp-dev@lists.fd.io > Subject: [vpp-dev] VPP nat ipfix logging problem, need to use > thread-specific vlib_main_t? > > Hello VPP experts, > > We have been using VPP for NAT44 for a while and it has been working fine, > but a few days ago when we tried turing on nat ipfix logging, vpp crashed. > It turned out that the problem went away if we used only a single thread, > so it seemed related to how threading was handled in the ipfix logging > code. The crash happened in different ways on different runs but often > seemed related to the snat_ipfix_send() function in > plugins/nat/nat_ipfix_logging.c. > > Having looked at the code in nat_ipfix_logging.c I have the following > theory about what goes wrong (I might have misunderstood something, if so > please correct me): > > In the the snat_ipfix_send() function, a vlib_main_t data structure is > used, a pointer to it is fetched in the following way: > > vlib_main_t *vm = frm->vlib_main; > > So the frm->vlib_main pointer comes from "frm" which has been set to > flow_report_main which is a global data structure from vnet/ipfix- > export/flow_report.c that as far as I can tell only exists once in memory > (not once per thread). This means that different threads calling the > snat_ipfix_send() function are using the same vlib_main_t data structure. > That is not how it should be, I think, instead each thread should be using > its own thread-specific vlib_main_t data structure. > > A suggestion for how to fix this is to replace the line > > vlib_main_t *vm = frm->vlib_main; > > with the following line > > vlib_main_t *vm = vlib_mains[thread_index]; > > in all places where worker threads are using such a vlib_main_t pointer. > Using vlib_mains[thread_index] means that we are picking the > thread-specific vlib_main_t data structure for the current thread, instead > of all threads using the same vlib_main_t. I pushed such a change to > gerrit, here: https://gerrit.fd.io/r/c/vpp/+/26359 > > That fix seems to solve the issue in my tests, vpp does not crash anymore > after the change. Please have a look at it and let me know if this seems > reasonable or if I have misunderstood something. > > Best regards, > Elias > >
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