Re: [dpdk-dev] [PATCH v3 0/2] Enhance Async Enqueue for Small Packets

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 12/25/20 9:28 AM, Jiayu Hu wrote:
> Async enqueue offloads large copies to DMA devices, and small copies
> are still performed by the CPU. However, it requires users to get
> enqueue completed packets by rte_vhost_poll_enqueue_completed(), even
> if they are completed by the CPU when rte_vhost_submit_enqueue_burst()
> returns. This design incurs extra overheads of tracking completed
> pktmbufs and function calls, thus degrading performance on small packets.
> 
> The first patch cleans up async enqueue code, and the second patch
> enables rte_vhost_submit_enqueue_burst() to return completed packets.
> 
> Change log
> ==========
> v3:
> - fix incorrect ret value when DMA ring is full
> - enhance description of API declaration and programmer guide
> v2:
> - fix typo
> - rename API variables
> - update programmer guide
> 
> Jiayu Hu (2):
>   vhost: cleanup async enqueue
>   vhost: enhance async enqueue for small packets
> 
>  doc/guides/prog_guide/vhost_lib.rst |   8 +-
>  lib/librte_vhost/rte_vhost_async.h  |  32 +++--
>  lib/librte_vhost/vhost.c            |  14 +-
>  lib/librte_vhost/vhost.h            |   7 +-
>  lib/librte_vhost/vhost_user.c       |   7 +-
>  lib/librte_vhost/virtio_net.c       | 258 ++++++++++++++++++++----------------
>  6 files changed, 185 insertions(+), 141 deletions(-)
> 

CI reports build failure with your series, because API changes are not
done in the examples:

FAILED: examples/dpdk-vhost.p/vhost_main.c.o
cc -Iexamples/dpdk-vhost.p -Iexamples -I../examples -Iexamples/vhost
-I../examples/vhost -I. -I.. -Iconfig -I../config
-Ilib/librte_eal/include -I../lib/librte_eal/include
-Ilib/librte_eal/linux/include -I../lib/librte_eal/linux/include
-Ilib/librte_eal/x86/include -I../lib/librte_eal/x86/include
-Ilib/librte_eal/common -I../lib/librte_eal/common -Ilib/librte_eal
-I../lib/librte_eal -Ilib/librte_kvargs -I../lib/librte_kvargs
-Ilib/librte_metrics -I../lib/librte_metrics -Ilib/librte_telemetry
-I../lib/librte_telemetry -Ilib/librte_mempool -I../lib/librte_mempool
-Ilib/librte_ring -I../lib/librte_ring -Ilib/librte_net
-I../lib/librte_net -Ilib/librte_mbuf -I../lib/librte_mbuf
-Ilib/librte_ethdev -I../lib/librte_ethdev -Ilib/librte_meter
-I../lib/librte_meter -Ilib/librte_cmdline -I../lib/librte_cmdline
-Ilib/librte_vhost -I../lib/librte_vhost -Ilib/librte_cryptodev
-I../lib/librte_cryptodev -Ilib/librte_hash -I../lib/librte_hash
-Ilib/librte_rcu -I../lib/librte_rcu -Ilib/librte_pci
-I../lib/librte_pci -Idrivers/raw/ioat -I../drivers/raw/ioat
-Ilib/librte_rawdev -I../lib/librte_rawdev -Idrivers/bus/pci
-I../drivers/bus/pci -I../drivers/bus/pci/linux -Idrivers/bus/vdev
-I../drivers/bus/vdev -fdiagnostics-color=always -pipe
-D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Werror -O3 -include
rte_config.h -Wextra -Wcast-qual -Wdeprecated -Wformat
-Wformat-nonliteral -Wformat-security -Wmissing-declarations
-Wmissing-prototypes -Wnested-externs -Wold-style-definition
-Wpointer-arith -Wsign-compare -Wstrict-prototypes -Wundef
-Wwrite-strings -Wno-missing-field-initializers -D_GNU_SOURCE
-march=native -Wno-format-truncation -DALLOW_EXPERIMENTAL_API -MD -MQ
examples/dpdk-vhost.p/vhost_main.c.o -MF
examples/dpdk-vhost.p/vhost_main.c.o.d -o
examples/dpdk-vhost.p/vhost_main.c.o -c ../examples/vhost/main.c
../examples/vhost/main.c: In function 'virtio_xmit':
../examples/vhost/main.c:817:9: error: too few arguments to function
'rte_vhost_submit_enqueue_burst'
   ret = rte_vhost_submit_enqueue_burst(dst_vdev->vid, VIRTIO_RXQ,
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from ../examples/vhost/ioat.h:10:0,
                 from ../examples/vhost/main.c:28:
../lib/librte_vhost/rte_vhost_async.h:171:10: note: declared here
 uint16_t rte_vhost_submit_enqueue_burst(int vid, uint16_t queue_id,
          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../examples/vhost/main.c: In function 'drain_eth_rx':
../examples/vhost/main.c:1126:19: error: too few arguments to function
'rte_vhost_submit_enqueue_burst'
   enqueue_count = rte_vhost_submit_enqueue_burst(vdev->vid,
                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from ../examples/vhost/ioat.h:10:0,
                 from ../examples/vhost/main.c:28:
../lib/librte_vhost/rte_vhost_async.h:171:10: note: declared here
 uint16_t rte_vhost_submit_enqueue_burst(int vid, uint16_t queue_id,
          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~