From: Ferruh Yigit <ferruh.yigit@amd.com>
To: Long Li <longli@microsoft.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 22:34:06 +0000 [thread overview]
Message-ID: <b1423042-03aa-41bf-af78-094f7022b019@amd.com> (raw)
In-Reply-To: <PH7PR21MB3263E4153A1FB73098D4A9BDCE7D2@PH7PR21MB3263.namprd21.prod.outlook.com>
On 1/30/2024 9:30 PM, Long Li wrote:
>> 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.
>
That is OK, using bulk alloc is reasonable approach, only can you please
document the impact (performance increase) in the commit log.
>>
>> <...>
>>
>>> @@ -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);
>
Nope, I am not talking about the 'mbufs' variable, I am talking about
mbuf pointers stored in the 'mbufs' array which are allocated by
'rte_pktmbuf_alloc_bulk()'.
next prev parent reply other threads:[~2024-01-30 22:34 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
2024-01-30 22:34 ` Ferruh Yigit [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=b1423042-03aa-41bf-af78-094f7022b019@amd.com \
--to=ferruh.yigit@amd.com \
--cc=andrew.rybchenko@oktetlabs.ru \
--cc=dev@dpdk.org \
--cc=longli@microsoft.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).