On Thu, Nov 05, 2020 at 10:35:45AM +0100, Morten Brørup wrote: > There is a simple alternative for applications with a single mbuf pool to > avoid accessing m->pool. > > We could add a global variable pointing to the single mbuf pool. > > It would be NULL by default. > > It would be set by rte_pktmbuf_pool_create() on first invocation, and reset > back to NULL on following invocations. (There would need to be a counter too, > to prevent setting it again on the third invocation.) > > All functions accessing m->pool would use the global mbuf pool pointer if > set, and otherwise use the m->pool pointer, like this: > > - rte_mempool_put(m->pool, m); > + rte_mempool_put(global_mbuf_pool ? global_mbuf_pool : m->pool, m); > > This optimization can be implemented without ABI breakage: > > Since m->pool is initialized as always, functions that are not modified to > use the global_mbuf_pool will simply continue using m->pool, not knowing that > a global mbuf pool exists. > Very interesting idea. Definitely worth considering. A TX function would only have to check the global variable once at the start of cleanup too, and if set, it can use bulk frees without any additional work.
/Bruce
