Re: [dpdk-dev] [PATCH v3] examples/vhost: remove async inflight packet counter

["Jiang, Cheng1" <cheng1.jiang@intel.com>]

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Wednesday, February 3, 2021 10:21 PM
> To: Jiang, Cheng1 <cheng1.jiang@intel.com>; Xia, Chenbo
> <chenbo.xia@intel.com>
> Cc: dev@dpdk.org; Hu, Jiayu <jiayu.hu@intel.com>; Yang, YvonneX
> <yvonnex.yang@intel.com>; Wang, Yinan <yinan.wang@intel.com>
> Subject: Re: [PATCH v3] examples/vhost: remove async inflight packet
> counter
> 
> 
> 
> On 2/3/21 2:42 PM, Jiang, Cheng1 wrote:
> >
> >
> >> -----Original Message-----
> >> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> >> Sent: Wednesday, February 3, 2021 8:55 PM
> >> To: Jiang, Cheng1 <cheng1.jiang@intel.com>; Xia, Chenbo
> >> <chenbo.xia@intel.com>
> >> Cc: dev@dpdk.org; Hu, Jiayu <jiayu.hu@intel.com>; Yang, YvonneX
> >> <yvonnex.yang@intel.com>; Wang, Yinan <yinan.wang@intel.com>
> >> Subject: Re: [PATCH v3] examples/vhost: remove async inflight packet
> >> counter
> >>
> >>
> >>
> >> On 2/3/21 1:11 PM, Jiang, Cheng1 wrote:
> >>> Hi,
> >>>
> >>>> -----Original Message-----
> >>>> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> >>>> Sent: Wednesday, February 3, 2021 5:52 PM
> >>>> To: Jiang, Cheng1 <cheng1.jiang@intel.com>; Xia, Chenbo
> >>>> <chenbo.xia@intel.com>
> >>>> Cc: dev@dpdk.org; Hu, Jiayu <jiayu.hu@intel.com>; Yang, YvonneX
> >>>> <yvonnex.yang@intel.com>; Wang, Yinan <yinan.wang@intel.com>
> >>>> Subject: Re: [PATCH v3] examples/vhost: remove async inflight
> >>>> packet counter
> >>>>
> >>>>
> >>>>
> >>>> On 2/2/21 7:17 AM, Cheng Jiang wrote:
> >>>>> Remove async inflight packet counter since there is no need to
> >>>>> keep tracking it. Increase MAX_ENQUEUED_SIZE to prevent packet
> >>>>> segment number tracking ring from being exhausted.
> >>>>
> >>>> Is that an optimization or a fix?
> >>>>
> >>>> If the former, let's move it to v21.05.
> >>>>
> >>>
> >>> I think it's a fix since there is no need to keep the inflight
> >>> packet counter,
> >> sorry I forget adding the fixes, I can submit a v4 to fix it.
> >> OK
> >>>>>
> >>>>> Fixes: a68ba8e0a6b6 ("examples/vhost: refactor vhost data path")
> >
> > Oh, I got fixes here, sorry for the miss.
> >
> >>>>>
> >>>>> Signed-off-by: Cheng Jiang <Cheng1.jiang@intel.com>
> >>>>> ---
> >>>>> v3: fixed fixes commit id in git log
> >>>>>
> >>>>> v2: fixed a typo
> >>>>>
> >>>>>  examples/vhost/ioat.h |  2 +-
> >>>>>  examples/vhost/main.c | 10 +---------  examples/vhost/main.h |  1
> >>>>> -
> >>>>>  3 files changed, 2 insertions(+), 11 deletions(-)
> >>>>>
> >>>>> diff --git a/examples/vhost/ioat.h b/examples/vhost/ioat.h index
> >>>>> 0a1dbb811..1aa28ed6a 100644
> >>>>> --- a/examples/vhost/ioat.h
> >>>>> +++ b/examples/vhost/ioat.h
> >>>>> @@ -11,7 +11,7 @@
> >>>>>
> >>>>>  #define MAX_VHOST_DEVICE 1024
> >>>>>  #define IOAT_RING_SIZE 4096
> >>>>> -#define MAX_ENQUEUED_SIZE 512
> >>>>> +#define It might be further simplified then 4096
> >>>>
> >>>> Basically, this the size of the ring size, correct?
> >>>> It might be further simplified then.
> >>>>
> >>>
> >>> Yes, it's a the size of packet tracking ring, and it should be no
> >>> less then
> >> IOAT_RING_SIZE for some corner cases.
> >>> I'm not sure I understand what you mean by saying It might be
> >>> further
> >> simplified then.
> >>
> >> I meant maybe in this case just use IOAT_RING_SIZE?
> >
> > I have thought about it before I use MAX_ENQUEUED_SIZE.
> > But actually MAX_ENQUEUED_SIZE is used to for packet tracking ring, and
> IOAT_RING_SIZE is for ioat ring.
> > Using IOAT_RING_SIZE for packet tracking ring, I think maybe it's not so
> logical and a little bit confusing. What do you think?
> 
> OK, let's keep it as is then.

Sure, then this is the last version of this patch.

Thanks,
Cheng

> 
> Thanks,
> Maxime
> 
> > Thanks,
> > Cheng
> >
> >>
> >>> Thanks,
> >>> Cheng
> >>>
> >>>>>
> >>>>>  struct dma_info {
> >>>>>  	struct rte_pci_addr addr;
> >>>>> diff --git a/examples/vhost/main.c b/examples/vhost/main.c index
> >>>>> e74fc8750..ca73e7086 100644
> >>>>> --- a/examples/vhost/main.c
> >>>>> +++ b/examples/vhost/main.c
> >>>>> @@ -831,11 +831,8 @@ complete_async_pkts(struct vhost_dev
> *vdev)
> >>>>>
> >>>>>  	complete_count = rte_vhost_poll_enqueue_completed(vdev->vid,
> >>>>>  					VIRTIO_RXQ, p_cpl,
> >>>> MAX_PKT_BURST);
> >>>>> -	if (complete_count) {
> >>>>> -		__atomic_sub_fetch(&vdev->nr_async_pkts,
> >>>> complete_count,
> >>>>> -			__ATOMIC_SEQ_CST);
> >>>>> +	if (complete_count)
> >>>>>  		free_pkts(p_cpl, complete_count);
> >>>>> -	}
> >>>>>  }
> >>>>>
> >>>>>  static __rte_always_inline void
> >>>>> @@ -878,8 +875,6 @@ drain_vhost(struct vhost_dev *vdev)
> >>>>>  		complete_async_pkts(vdev);
> >>>>>  		ret = rte_vhost_submit_enqueue_burst(vdev->vid,
> >>>> VIRTIO_RXQ,
> >>>>>  					m, nr_xmit, m_cpu_cpl,
> >>>> &cpu_cpl_nr);
> >>>>> -		__atomic_add_fetch(&vdev->nr_async_pkts, ret -
> >>>> cpu_cpl_nr,
> >>>>> -				__ATOMIC_SEQ_CST);
> >>>>>
> >>>>>  		if (cpu_cpl_nr)
> >>>>>  			free_pkts(m_cpu_cpl, cpu_cpl_nr); @@ -1210,9
> >> +1205,6 @@
> >>>>> drain_eth_rx(struct vhost_dev *vdev)
> >>>>>  		enqueue_count = rte_vhost_submit_enqueue_burst(vdev-
> >>>>> vid,
> >>>>>  					VIRTIO_RXQ, pkts, rx_count,
> >>>>>  					m_cpu_cpl, &cpu_cpl_nr);
> >>>>> -		__atomic_add_fetch(&vdev->nr_async_pkts,
> >>>>> -					enqueue_count - cpu_cpl_nr,
> >>>>> -					__ATOMIC_SEQ_CST);
> >>>>>  		if (cpu_cpl_nr)
> >>>>>  			free_pkts(m_cpu_cpl, cpu_cpl_nr);
> >>>>>
> >>>>> diff --git a/examples/vhost/main.h b/examples/vhost/main.h index
> >>>>> 2d6c05fd7..0ccdce4b4 100644
> >>>>> --- a/examples/vhost/main.h
> >>>>> +++ b/examples/vhost/main.h
> >>>>> @@ -51,7 +51,6 @@ struct vhost_dev {
> >>>>>  	uint64_t features;
> >>>>>  	size_t hdr_len;
> >>>>>  	uint16_t nr_vrings;
> >>>>> -	uint64_t nr_async_pkts;
> >>>>>  	struct rte_vhost_memory *mem;
> >>>>>  	struct device_statistics stats;
> >>>>>  	TAILQ_ENTRY(vhost_dev) global_vdev_entry;
> >>>>> --
> >>>>> 2.29.2
> >>>>>
> >>>
> >