Re: [dpdk-dev] Multi-thread mempool usage

[Matteo Lanzuisi <m.lanzuisi@resi.it>]

Any suggestion? any idea about this behaviour?

Il 08/08/2018 11:56, Matteo Lanzuisi ha scritto:
> Hi all,
>
> recently I began using "dpdk-17.11-11.el7.x86_64" rpm (RedHat rpm) on 
> RedHat 7.5 kernel 3.10.0-862.6.3.el7.x86_64 as a porting of an 
> application from RH6 to RH7. On RH6 I used dpdk-2.2.0.
>
> This application is made up by one or more threads (each one on a 
> different logical core) reading packets from i40e interfaces.
>
> Each thread can call the following code lines when receiving a 
> specific packet:
>
> RTE_LCORE_FOREACH(lcore_id)
> {
>         result = 
> rte_mempool_get(cea_main_lcore_conf[lcore_id].de_conf.cmd_pool, 
> (VOID_P *) &new_work);        // mempools are created one for each 
> logical core
>         if (((uint64_t)(new_work)) < 0x7f0000000000)
>             printf("Result %d, lcore di partenza %u, lcore di 
> ricezione %u, pointer %p\n", result, rte_lcore_id(), lcore_id, 
> new_work);    // debug print, on my server it should never happen but 
> with multi-thread happens always on the last logical core!!!!
>         if (result == 0)
>         {
>             new_work->command = command; // usage of the memory gotten 
> from the mempool... <<<<<- here is where the application crashes!!!!
>             result = 
> rte_ring_enqueue(cea_main_lcore_conf[lcore_id].de_conf.cmd_ring, 
> (VOID_P) new_work);    // enqueues the gotten buffer on the rings of 
> all lcores
>             // check on result value ...
>         }
>         else
>         {
>             // do something if result != 0 ...
>         }
> }
>
> This code worked perfectly (never had an issue) on dpdk-2.2.0, while 
> if I use more than 1 thread doing these operations on dpdk-17.11 it 
> happens that after some times the "new_work" pointer is not a good 
> one, and the application crashes when using that pointer.
>
> It seems that these lines cannot be used by more than one thread 
> simultaneously. I also used many 2017 and 2018 dpdk versions without 
> success.
>
> Is this code possible on the new dpdk versions? Or have I to change my 
> application so that this code is called just by one lcore at a time?
>
> Matteo
>
>
>

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