From: Yuanhan Liu <yuanhan.liu@linux.intel.com>
To: "Xie, Huawei" <huawei.xie@intel.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
"dev@dpdk.org" <dev@dpdk.org>,
Victor Kaplansky <vkaplans@redhat.com>
Subject: Re: [dpdk-dev] [PATCH v2 1/7] vhost: refactor rte_vhost_dequeue_burst
Date: Mon, 7 Mar 2016 10:48:38 +0800 [thread overview]
Message-ID: <20160307024838.GY14300@yliu-dev.sh.intel.com> (raw)
In-Reply-To: <C37D651A908B024F974696C65296B57B4C636DCF@SHSMSX101.ccr.corp.intel.com>
On Mon, Mar 07, 2016 at 02:32:46AM +0000, Xie, Huawei wrote:
> On 3/4/2016 10:15 AM, Yuanhan Liu wrote:
> > On Thu, Mar 03, 2016 at 04:30:42PM +0000, Xie, Huawei wrote:
> >> On 2/18/2016 9:48 PM, Yuanhan Liu wrote:
> >>> + mbuf_avail = 0;
> >>> + mbuf_offset = 0;
> >>> + while (desc_avail || (desc->flags & VRING_DESC_F_NEXT) != 0) {
> >>> + /* This desc reachs to its end, get the next one */
> >>> + if (desc_avail == 0) {
> >>> + desc = &vq->desc[desc->next];
> >>> +
> >>> + desc_addr = gpa_to_vva(dev, desc->addr);
> >>> + rte_prefetch0((void *)(uintptr_t)desc_addr);
> >>> +
> >>> + desc_offset = 0;
> >>> + desc_avail = desc->len;
> >>> +
> >>> + PRINT_PACKET(dev, (uintptr_t)desc_addr, desc->len, 0);
> >>> + }
> >>> +
> >>> + /*
> >>> + * This mbuf reachs to its end, get a new one
> >>> + * to hold more data.
> >>> + */
> >>> + if (mbuf_avail == 0) {
> >>> + cur = rte_pktmbuf_alloc(mbuf_pool);
> >>> + if (unlikely(!cur)) {
> >>> + RTE_LOG(ERR, VHOST_DATA, "Failed to "
> >>> + "allocate memory for mbuf.\n");
> >>> + if (head)
> >>> + rte_pktmbuf_free(head);
> >>> + return NULL;
> >>> + }
> >> We could always allocate the head mbuf before the loop, then we save the
> >> following branch and make the code more streamlined.
> >> It reminds me that this change prevents the possibility of mbuf bulk
> >> allocation, one solution is we pass the head mbuf from an additional
> >> parameter.
> > Yep, that's also something I have thought of.
> >
> >> Btw, put unlikely before the check of mbuf_avail and checks elsewhere.
> > I don't think so. It would benifit for the small packets. What if,
> > however, when TSO or jumbo frame is enabled that we have big packets?
>
> Prefer to favor the path that packet could fit in one mbuf.
Hmmm, why? While I know that TSO and mergeable buf is disable by default
in our vhost example vhost-switch, they are enabled by default in real
life.
> Btw, not specially to this, return "m = copy_desc_to_mbuf(dev, vq,
> desc_indexes[i], mbuf_pool)", failure case is unlikely to happen, so add
> unlikely for the check if (m == NULL) there. Please check all branches
> elsewhere.
Thanks for the remind, will have a detail check.
--yliu
next prev parent reply other threads:[~2016-03-07 2:46 UTC|newest]
Thread overview: 84+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-03 6:06 [dpdk-dev] [PATCH 0/5 for 2.3] vhost rxtx refactor Yuanhan Liu
2015-12-03 6:06 ` [dpdk-dev] [PATCH 1/5] vhost: refactor rte_vhost_dequeue_burst Yuanhan Liu
2015-12-03 7:02 ` Stephen Hemminger
2015-12-03 7:25 ` Yuanhan Liu
2015-12-03 7:03 ` Stephen Hemminger
2015-12-12 6:55 ` Rich Lane
2015-12-14 1:55 ` Yuanhan Liu
2016-01-26 10:30 ` Xie, Huawei
2016-01-27 3:26 ` Yuanhan Liu
2016-01-27 6:12 ` Xie, Huawei
2016-01-27 6:16 ` Yuanhan Liu
2015-12-03 6:06 ` [dpdk-dev] [PATCH 2/5] vhost: refactor virtio_dev_rx Yuanhan Liu
2015-12-11 20:42 ` Rich Lane
2015-12-14 1:47 ` Yuanhan Liu
2016-01-21 13:50 ` Jérôme Jutteau
2016-01-27 3:27 ` Yuanhan Liu
2015-12-03 6:06 ` [dpdk-dev] [PATCH 3/5] vhost: refactor virtio_dev_merge_rx Yuanhan Liu
2015-12-03 6:06 ` [dpdk-dev] [PATCH 4/5] vhost: do not use rte_memcpy for virtio_hdr copy Yuanhan Liu
2016-01-27 2:46 ` Xie, Huawei
2016-01-27 3:22 ` Yuanhan Liu
2016-01-27 5:56 ` Xie, Huawei
2016-01-27 6:02 ` Yuanhan Liu
2016-01-27 6:16 ` Xie, Huawei
2016-01-27 6:35 ` Yuanhan Liu
2015-12-03 6:06 ` [dpdk-dev] [PATCH 5/5] vhost: don't use unlikely for VIRTIO_NET_F_MRG_RXBUF detection Yuanhan Liu
2016-02-17 22:50 ` [dpdk-dev] [PATCH 0/5 for 2.3] vhost rxtx refactor Thomas Monjalon
2016-02-18 4:09 ` Yuanhan Liu
2016-02-18 13:49 ` [dpdk-dev] [PATCH v2 0/7] " Yuanhan Liu
2016-02-18 13:49 ` [dpdk-dev] [PATCH v2 1/7] vhost: refactor rte_vhost_dequeue_burst Yuanhan Liu
2016-03-03 16:21 ` Xie, Huawei
2016-03-04 2:21 ` Yuanhan Liu
2016-03-07 2:19 ` Xie, Huawei
2016-03-07 2:44 ` Yuanhan Liu
2016-03-03 16:30 ` Xie, Huawei
2016-03-04 2:17 ` Yuanhan Liu
2016-03-07 2:32 ` Xie, Huawei
2016-03-07 2:48 ` Yuanhan Liu [this message]
2016-03-07 2:59 ` Xie, Huawei
2016-03-07 6:14 ` Yuanhan Liu
2016-03-03 17:19 ` Xie, Huawei
2016-03-04 2:11 ` Yuanhan Liu
2016-03-07 2:55 ` Xie, Huawei
2016-03-03 17:40 ` Xie, Huawei
2016-03-04 2:32 ` Yuanhan Liu
2016-03-07 3:02 ` Xie, Huawei
2016-03-07 3:03 ` Xie, Huawei
2016-02-18 13:49 ` [dpdk-dev] [PATCH v2 2/7] vhost: refactor virtio_dev_rx Yuanhan Liu
2016-03-07 3:34 ` Xie, Huawei
2016-03-08 12:27 ` Yuanhan Liu
2016-02-18 13:49 ` [dpdk-dev] [PATCH v2 3/7] vhost: refactor virtio_dev_merge_rx Yuanhan Liu
2016-03-07 6:22 ` Xie, Huawei
2016-03-07 6:36 ` Yuanhan Liu
2016-03-07 6:38 ` Xie, Huawei
2016-03-07 6:51 ` Yuanhan Liu
2016-03-07 7:03 ` Xie, Huawei
2016-03-07 7:16 ` Xie, Huawei
2016-03-07 8:20 ` Yuanhan Liu
2016-03-07 7:52 ` Xie, Huawei
2016-03-07 8:38 ` Yuanhan Liu
2016-03-07 9:27 ` Xie, Huawei
2016-02-18 13:49 ` [dpdk-dev] [PATCH v2 4/7] vhost: do not use rte_memcpy for virtio_hdr copy Yuanhan Liu
2016-03-07 1:20 ` Xie, Huawei
2016-03-07 4:20 ` Stephen Hemminger
2016-03-07 5:24 ` Xie, Huawei
2016-03-07 6:21 ` Yuanhan Liu
2016-02-18 13:49 ` [dpdk-dev] [PATCH v2 5/7] vhost: don't use unlikely for VIRTIO_NET_F_MRG_RXBUF detection Yuanhan Liu
2016-02-18 13:49 ` [dpdk-dev] [PATCH v2 6/7] vhost: do sanity check for desc->len Yuanhan Liu
2016-02-18 13:49 ` [dpdk-dev] [PATCH v2 7/7] vhost: do sanity check for desc->next Yuanhan Liu
2016-03-07 3:10 ` Xie, Huawei
2016-03-07 6:57 ` Yuanhan Liu
2016-02-29 16:06 ` [dpdk-dev] [PATCH v2 0/7] vhost rxtx refactor Thomas Monjalon
2016-03-01 6:01 ` Yuanhan Liu
2016-03-10 4:32 ` [dpdk-dev] [PATCH v3 0/8] vhost rxtx refactor and fixes Yuanhan Liu
2016-03-10 4:32 ` [dpdk-dev] [PATCH v3 1/8] vhost: refactor rte_vhost_dequeue_burst Yuanhan Liu
2016-03-10 4:32 ` [dpdk-dev] [PATCH v3 2/8] vhost: refactor virtio_dev_rx Yuanhan Liu
2016-03-10 4:32 ` [dpdk-dev] [PATCH v3 3/8] vhost: refactor virtio_dev_merge_rx Yuanhan Liu
2016-03-11 16:18 ` Thomas Monjalon
2016-03-14 7:35 ` [dpdk-dev] [PATCH v4 " Yuanhan Liu
2016-03-10 4:32 ` [dpdk-dev] [PATCH v3 4/8] vhost: do not use rte_memcpy for virtio_hdr copy Yuanhan Liu
2016-03-10 4:32 ` [dpdk-dev] [PATCH v3 5/8] vhost: don't use unlikely for VIRTIO_NET_F_MRG_RXBUF detection Yuanhan Liu
2016-03-10 4:32 ` [dpdk-dev] [PATCH v3 6/8] vhost: do sanity check for desc->len Yuanhan Liu
2016-03-10 4:32 ` [dpdk-dev] [PATCH v3 7/8] vhost: do sanity check for desc->next against with vq->size Yuanhan Liu
2016-03-10 4:32 ` [dpdk-dev] [PATCH v3 8/8] vhost: avoid dead loop chain Yuanhan Liu
2016-03-14 23:09 ` [dpdk-dev] [PATCH v3 0/8] vhost rxtx refactor and fixes Thomas Monjalon
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