On 10/01/2023 20:27, Ilya Maximets wrote:
On 1/10/23 19:27, Kevin Traynor wrote:
On 09/01/2023 18:28, Ilya Maximets wrote:
rte_pktmbuf_free_bulk() function was introduced in 19.11 and became
stable in 21.11. Use it to free arrays of mbufs instead of freeing
packets one by one.
In simple V2V testing with 64B packets, 2 PMD threads and bidirectional
traffic this change improves performance by 3.5 - 4.5 %.
Signed-off-by: Ilya Maximets <[email protected]>
---
lib/netdev-dpdk.c | 13 +++----------
1 file changed, 3 insertions(+), 10 deletions(-)
diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index 5e2d64651..28a04bb7f 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -2286,13 +2286,8 @@ netdev_dpdk_eth_tx_burst(struct netdev_dpdk *dev, int
qid,
}
if (OVS_UNLIKELY(nb_tx != cnt)) {
- /* Free buffers, which we couldn't transmit, one at a time (each
- * packet could come from a different mempool) */
- int i;
-
- for (i = nb_tx; i < cnt; i++) {
- rte_pktmbuf_free(pkts[i]);
- }
+ /* Free buffers, which we couldn't transmit. */
+ rte_pktmbuf_free_bulk(&pkts[nb_tx], cnt - nb_tx);
Is this API ok with freeing pkts from different mempools?
The documentation seems to imply it is, but I wasn't sure from looking
at the code - specifically that there is an additional rte_mempool_put_bulk()
for a single mempool outside the loop.
It should work for mbufs from different pools. The function collects
mbufs into the 'pending' array and calls rte_mempool_put_bulk() once
it hits mbuf from a different pool. See __rte_pktmbuf_free_seg_via_array().
The additional rte_mempool_put_bulk() in the end takes care of remaining
mbufs that are not freed by __rte_pktmbuf_free_seg_via_array(). These
all should be from the same pool.
got it - thanks.
There is also a unit test - test_pktmbuf_pool_bulk() - that tests with
different mempools.
I vaguely remember that there was an API to bulk free mbufs that was
suitable only when all mbufs are from the same pool. And the comment
that I'm removing here in the code also suggests that. But I don't
remember what that was.
Best regards, Ilya Maximets.
Acked-by: Kevin Traynor <[email protected]>
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