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From: Ferruh Yigit <ferruh.yigit@amd.com>
To: longli@microsoft.com, Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Cc: dev@dpdk.org
Subject: Re: [Patch v2] net/mana: use rte_pktmbuf_alloc_bulk for allocating RX WQEs
Date: Tue, 30 Jan 2024 10:19:32 +0000	[thread overview]
Message-ID: <b49e8410-5cae-4535-90d4-b4a462d2161b@amd.com> (raw)
In-Reply-To: <1706577181-27842-1-git-send-email-longli@linuxonhyperv.com>

On 1/30/2024 1:13 AM, longli@linuxonhyperv.com wrote:
> From: Long Li <longli@microsoft.com>
> 
> Instead of allocating mbufs one by one during RX, use rte_pktmbuf_alloc_bulk()
> to allocate them in a batch.
> 
> Signed-off-by: Long Li <longli@microsoft.com>
>

Can you please quantify the performance improvement (as percentage),
this clarifies the impact of the modification.

<...>

> @@ -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?



  reply	other threads:[~2024-01-30 10:19 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 [this message]
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
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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