Re: [PATCH] event/eth_tx: prefetch mbuf headers

[Mattias Rönnblom]

On 2025-03-28 06:43, Mattias Rönnblom wrote:
Prefetch mbuf headers, resulting in ~10% throughput improvement when
the Ethernet RX and TX Adapters are hosted on the same core (likely
~2x in case a dedicated TX core is used).
Signed-off-by: Mattias Rönnblom <mattias.ronnb...@ericsson.com>
Tested-by: Peter Nilsson <peter.j.nils...@ericsson.com>

What should be added is that what's been tested is the 
non-RTE_EVENT_TYPE_VECTOR case.

---
  lib/eventdev/rte_event_eth_tx_adapter.c | 20 ++++++++++++++++++++
  1 file changed, 20 insertions(+)

diff --git a/lib/eventdev/rte_event_eth_tx_adapter.c 
b/lib/eventdev/rte_event_eth_tx_adapter.c
index 67fff8b7d6..d740ae00f9 100644
--- a/lib/eventdev/rte_event_eth_tx_adapter.c
+++ b/lib/eventdev/rte_event_eth_tx_adapter.c
@@ -598,6 +598,12 @@ txa_process_event_vector(struct txa_service_data *txa,
        return nb_tx;
  }
  
+static inline void
+txa_prefetch_mbuf(struct rte_mbuf *mbuf)
+{
+       rte_mbuf_prefetch_part1(mbuf);
+}
+
  static void
  txa_service_tx(struct txa_service_data *txa, struct rte_event *ev,
        uint32_t n)
@@ -608,6 +614,20 @@ txa_service_tx(struct txa_service_data *txa, struct 
rte_event *ev,
  
  	stats = &txa->stats;
  
+	for (i = 0; i < n; i++) {
+               struct rte_event *event = &ev[i];
+
+               if (unlikely(event->event_type & RTE_EVENT_TYPE_VECTOR)) {
+                       struct rte_event_vector *vec = event->vec;
+                       struct rte_mbuf **mbufs = vec->mbufs;
+                       uint32_t k;
+
+                       for (k = 0; k < vec->nb_elem; k++)
+                               txa_prefetch_mbuf(mbufs[k]);
+               } else
+                       txa_prefetch_mbuf(event->mbuf);
+       }
+
        nb_tx = 0;
        for (i = 0; i < n; i++) {
                uint16_t port;