From: Long Li <longli@microsoft.com>
To: Ferruh Yigit <ferruh.yigit@amd.com>,
Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: RE: [Patch v2] net/mana: use rte_pktmbuf_alloc_bulk for allocating RX WQEs
Date: Tue, 30 Jan 2024 21:30:04 +0000 [thread overview]
Message-ID: <PH7PR21MB3263E4153A1FB73098D4A9BDCE7D2@PH7PR21MB3263.namprd21.prod.outlook.com> (raw)
In-Reply-To: <b49e8410-5cae-4535-90d4-b4a462d2161b@amd.com>
> Can you please quantify the performance improvement (as percentage), this
> clarifies the impact of the modification.
I didn't see any meaningful performance improvements in benchmarks. However, this should improve CPU cycles and reduce potential locking conflicts in real-world applications.
Using batch allocation was one of the review comments during initial driver submission, suggested by Stephen Hemminger. I promised to fix it at that time. Sorry it took a while to submit this patch.
>
> <...>
>
> > @@ -121,19 +115,32 @@ mana_alloc_and_post_rx_wqe(struct mana_rxq
> *rxq)
> > * Post work requests for a Rx queue.
> > */
> > static int
> > -mana_alloc_and_post_rx_wqes(struct mana_rxq *rxq)
> > +mana_alloc_and_post_rx_wqes(struct mana_rxq *rxq, uint32_t count)
> > {
> > int ret;
> > uint32_t i;
> > + struct rte_mbuf **mbufs;
> > +
> > + mbufs = rte_calloc_socket("mana_rx_mbufs", count, sizeof(struct
> rte_mbuf *),
> > + 0, rxq->mp->socket_id);
> > + if (!mbufs)
> > + return -ENOMEM;
> >
>
> 'mbufs' is temporarily storage for allocated mbuf pointers, why not allocate if from
> stack instead, can be faster and easier to manage:
> "struct rte_mbuf *mbufs[count]"
>
>
> > +
> > + ret = rte_pktmbuf_alloc_bulk(rxq->mp, mbufs, count);
> > + if (ret) {
> > + DP_LOG(ERR, "failed to allocate mbufs for RX");
> > + rxq->stats.nombuf += count;
> > + goto fail;
> > + }
> >
> > #ifdef RTE_ARCH_32
> > rxq->wqe_cnt_to_short_db = 0;
> > #endif
> > - for (i = 0; i < rxq->num_desc; i++) {
> > - ret = mana_alloc_and_post_rx_wqe(rxq);
> > + for (i = 0; i < count; i++) {
> > + ret = mana_post_rx_wqe(rxq, mbufs[i]);
> > if (ret) {
> > DP_LOG(ERR, "failed to post RX ret = %d", ret);
> > - return ret;
> > + goto fail;
> >
>
> This may leak memory. There are allocated mbufs, if exit from loop here and free
> 'mubfs' variable, how remaining mubfs will be freed?
Mbufs are always freed after fail:
fail:
rte_free(mbufs);
>
next prev parent reply other threads:[~2024-01-30 21:30 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-25 2:42 [PATCH] " longli
2024-01-26 0:29 ` Stephen Hemminger
2024-01-26 1:13 ` Long Li
2024-01-30 1:13 ` [Patch v2] " longli
2024-01-30 10:19 ` Ferruh Yigit
2024-01-30 16:43 ` Stephen Hemminger
2024-01-30 18:05 ` Tyler Retzlaff
2024-01-30 22:42 ` Ferruh Yigit
2024-02-01 3:55 ` Long Li
2024-02-01 10:52 ` Ferruh Yigit
2024-02-02 1:21 ` Long Li
2024-02-01 16:33 ` Tyler Retzlaff
2024-02-02 1:22 ` Long Li
2024-01-30 21:30 ` Long Li [this message]
2024-01-30 22:34 ` Ferruh Yigit
2024-01-30 22:36 ` Long Li
2024-02-01 3:45 ` [Patch v3] " longli
2024-02-01 16:16 ` Tyler Retzlaff
2024-02-01 19:41 ` Long Li
2024-02-02 1:19 ` [Patch v4] net/mana: use rte_pktmbuf_alloc_bulk for allocating RX mbufs longli
2024-02-02 16:24 ` Stephen Hemminger
2024-02-06 18:06 ` Ferruh Yigit
2024-02-07 4:50 ` Long Li
2024-02-09 0:02 ` [Patch v5] net/mana: use rte_pktmbuf_alloc_bulk for allocating RX WQEs longli
2024-02-09 17:46 ` Ferruh Yigit
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