Re: [dpdk-dev] [PATCH v1] virtio: Use cpuflag for vector api

["Qiu, Michael" <michael.qiu@intel.com>]

On 3/1/2016 5:46 PM, Santosh Shukla wrote:
> On Tue, Mar 1, 2016 at 2:41 PM, Qiu, Michael <michael.qiu@intel.com> wrote:
>> On 2/26/2016 4:53 PM, Santosh Shukla wrote:
>>> Check cpuflag macro before using vectored api.
>>> -virtio_recv_pkts_vec() uses _sse3__ simd instruction for now so added cpuflag.
>>> - Also wrap other vectored freind api ie..
>>> 1) virtqueue_enqueue_recv_refill_simple
>>> 2) virtio_rxq_vec_setup
>>>
>>> todo:
>>> 1) Move virtio_recv_pkts_vec() implementation to
>>>    drivers/virtio/virtio_vec_<arch>.h file.
>>> 2) Remove use_simple_rxtx flag, so that virtio/virtio_vec_<arch>.h
>>>    files to provide vectored/non-vectored rx/tx apis.
>>>
>>> Signed-off-by: Santosh Shukla <sshukla@mvista.com>
>>> ---
>>> - v1: This is a rework of patch [1].
>>> Note: This patch will let non-x86 arch to use virtio pmd.
>>>
>>> [1] http://dpdk.org/dev/patchwork/patch/10429/
>>>
>>>  drivers/net/virtio/virtio_rxtx.c        |   16 +++++++++++++++-
>>>  drivers/net/virtio/virtio_rxtx.h        |    2 ++
>>>  drivers/net/virtio/virtio_rxtx_simple.c |   11 ++++++++++-
>>>  3 files changed, 27 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
>>> index 41a1366..ec0b8de 100644
>>> --- a/drivers/net/virtio/virtio_rxtx.c
>>> +++ b/drivers/net/virtio/virtio_rxtx.c
>>> @@ -67,7 +67,9 @@
>>>  #define VIRTIO_SIMPLE_FLAGS ((uint32_t)ETH_TXQ_FLAGS_NOMULTSEGS | \
>>>       ETH_TXQ_FLAGS_NOOFFLOADS)
>>>
>>> +#ifdef RTE_MACHINE_CPUFLAG_SSSE3
>>>  static int use_simple_rxtx;
>>> +#endif
>>>
>>>
>> I don't think so much #ifdef ... #endif in *.c file is a good choice.
>> Would you consider let it only in header file like:
>>
>> in drivers/net/virtio/virtio_rxtx.h
>>
>> [...]
>>
>> #ifdef RTE_MACHINE_CPUFLAG_SSSE3
>> int virtio_rxq_vec_setup(struct virtqueue *rxq);
>>
>> int virtqueue_enqueue_recv_refill_simple(struct virtqueue *vq,
>>         struct rte_mbuf *m);
>> #else
>> int virtio_rxq_vec_setup(__rte_unused struct virtqueue *rxq) {return -1;}
>> int virtqueue_enqueue_recv_refill_simple(__rte_unused struct virtqueue *vq,
>>                                          __rte_unused struct rte_mbuf *m) {
>>         return -1;
>> }
>> #endif
>>
>> and remove most #ifdef ... #endif in *.c file.
>>
> I guess, above approach wont work for non-x86 arch, ad those func are
> dummy, right? also code wont build for arm/non-86 arch because
> tx/rx_pkt_burst callback will be using x86 specific virtio vec rx/tx
> api.

You may right, but you really need to reduce the #ifdef in *.c files.

Thanks,
Michael

>> Thanks,
>> Michael