Hi Gage, On Mon, Sep 21, 2020 at 03:42:28PM +0000, Eads, Gage wrote: > Hi Olivier, > > <snip> > > > > +Stack Mempool Driver > > > +==================== > > > + > > > +**rte_mempool_stack** is a pure software mempool driver based on the > > > +``rte_stack`` DPDK library. A stack-based mempool is often better suited > > > to > > > +packet-processing workloads than a ring-based mempool, since its LIFO > > behavior > > > +results in better temporal locality and a minimal memory footprint even > > > if the > > > +mempool is over-provisioned. > > > > Would it make sense to give an example of a use-case where the stack > > driver should be used in place of the standard ring-based one? > > > > In most run-to-completion applications, the mbufs stay in per-core > > caches, so changing the mempool driver won't have a big impact. However, > > I suspect that for applications using a pipeline model (ex: rx on core0, > > tx on core1), the stack model would be more efficient. Is it something > > that you measured? If yes, it would be useful to explain this in the > > documentation. > > > > Good point, I was overlooking the impact of the per-core caches. I've seen > data showing > better overall packet throughput with the stack mempool, and indeed that was > a pipelined > application. How about this re-write? > > " > **rte_mempool_stack** is a pure software mempool driver based on the > ``rte_stack`` DPDK library. For run-to-completion workloads with sufficiently > large per-lcore caches, the mbufs will likely stay in the per-lcore caches > and the > mempool type (ring, stack, etc.) will have a negligible impact on > performance. However > a stack-based mempool is often better suited to pipelined packet-processing > workloads > (which allocate and free mbufs on different lcores) than a ring-based > mempool, since its > LIFO behavior results in better temporal locality and a minimal memory > footprint even > if the mempool is over-provisioned. Users are encouraged to benchmark with > multiple > mempool types to determine which works best for their specific application. > "
Yes, this is clear, thanks! Olivier
