Hi again, > From: Yoshihiro Shimoda, Sent: Monday, May 10, 2021 7:30 PM > > > From: Sergei Shtylyov, Sent: Sunday, May 9, 2021 7:22 PM > > > > On 08.05.2021 23:47, Sergei Shtylyov wrote: > > > > > Posting a review of the already commited (over my head) patch. It would have > > > been appropriate if the patch looked OK but it's not. :-/ > > > > > >> When a lot of frames were received in the short term, the driver > > >> caused a stuck of receiving until a new frame was received. For example, > > >> the following command from other device could cause this issue. > > >> > > >> $ sudo ping -f -l 1000 -c 1000 <this driver's ipaddress> > > > > > > -l is essential here, right? > > Yes. > > > > Have you tried testing sh_eth sriver like that, BTW? > > > > It's driver! :-) > > I have not tried testing sh_eth driver yet. I'll test it after I got an actual board. I could reproduce a similar issue on R-Car Gen2 with sh_eth driver if the RX ring size is 1024 like the ravb driver. Also, I confirmed a similar patch for sh_eth driver could fix the issue. So, I'll send a patch later. Best regards, Yoshihiro Shimoda > > >> The previous code always cleared the interrupt flag of RX but checks > > >> the interrupt flags in ravb_poll(). So, ravb_poll() could not call > > >> ravb_rx() in the next time until a new RX frame was received if > > >> ravb_rx() returned true. To fix the issue, always calls ravb_rx() > > >> regardless the interrupt flags condition. > > > > > > That bacially defeats the purpose of IIUC... > > ^ NAPI, > > > > I was sure I typed NAPI here, yet it got lost in the edits. :-) > > I could not understand "that" (calling ravb_rx() regardless the interrupt > flags condition) defeats the purpose of NAPI. According to an article on > the Linux Foundation wiki [1], one of the purpose of NAPI is "Interrupt mitigation". > In poll(), the interrupts are already disabled, and ravb_rx() will check the > descriptor's status. So, this patch keeps the "Interrupt mitigation" IIUC. > > [1] > https://wiki.linuxfoundation.org/networking/napi > > Best regards, > Yoshihiro Shimoda
