On 2022/10/27 17:03, Gal Pressman wrote: > On 27/10/2022 03:49, Yunsheng Lin wrote: >> On 2022/10/26 22:00, Gal Pressman wrote: >>> On 18/11/2021 14:12, Guangbin Huang wrote: >>>> From: Hao Chen <chenhao288@xxxxxxxxxxxxx> >>>> >>>> This series add support to set/get tx copybreak buf size and rx buf len via >>>> ethtool and hns3 driver implements them. >>>> >>>> Tx copybreak buf size is used for tx copybreak feature which for small size >>>> packet or frag. Use ethtool --get-tunable command to get it, and ethtool >>>> --set-tunable command to set it, examples are as follow: >>>> >>>> 1. set tx spare buf size to 102400: >>>> $ ethtool --set-tunable eth1 tx-buf-size 102400 >>>> >>>> 2. get tx spare buf size: >>>> $ ethtool --get-tunable eth1 tx-buf-size >>>> tx-buf-size: 102400 >>> Hi Guangbin, >>> Can you please clarify the difference between TX copybreak and TX >>> copybreak buf size? >> Hi Gal, >> 'TX copybreak buf size' is the size of buffer allocated to a queue >> in order to support copybreak handling when skb->len <= 'TX copybreak', >> >> see hns3_can_use_tx_bounce() for 'TX copybreak' and >> hns3_init_tx_spare_buffer() for 'TX copybreak buf size'. > > Thanks Yunsheng! > IIUC, there's a single buffer per TX queue, not per TX packet, correct? Yes. > > One way to implement TX copybreak is using an inline WQE, where the WQE > itself serves as the bounce buffer, sounds like 'TX copybreak buf size' > cannot be used in such case? If TX copybreak is using an inline WQE, I suppose 'TX copybreak buf size' is not needed. > . >
