On Fri, 8 May 2020 at 15:01, Maxim Mikityanskiy <maximmi@xxxxxxxxxxxx> wrote: > > On 2020-05-08 15:27, Björn Töpel wrote: > > On 2020-05-08 13:55, Maxim Mikityanskiy wrote: > >> On 2020-05-07 13:42, Björn Töpel wrote: > >>> From: Björn Töpel <bjorn.topel@xxxxxxxxx> > >>> > >>> Use the new MEM_TYPE_XSK_BUFF_POOL API in lieu of MEM_TYPE_ZERO_COPY in > >>> mlx5e. It allows to drop a lot of code from the driver (which is now > >>> common in AF_XDP core and was related to XSK RX frame allocation, DMA > >>> mapping, etc.) and slightly improve performance. > >>> > >>> rfc->v1: Put back the sanity check for XSK params, use XSK API to get > >>> the total headroom size. (Maxim) > >>> > >>> Signed-off-by: Björn Töpel <bjorn.topel@xxxxxxxxx> > >>> Signed-off-by: Maxim Mikityanskiy <maximmi@xxxxxxxxxxxx> > >> > >> I did some functional and performance tests. > >> > >> Unfortunately, something is wrong with the traffic: I get zeros in > >> XDP_TX, XDP_PASS and XSK instead of packet data. I set DEBUG_HEXDUMP > >> in xdpsock, and it shows the packets of the correct length, but all > >> bytes are 0 after these patches. It might be wrong xdp_buff pointers, > >> however, I still have to investigate it. Björn, does it also affect > >> Intel drivers, or is it Mellanox-specific? > >> > > > > Are you getting zeros for TX, PASS *and* in xdpsock (REDIRECT:ed > > packets), or just TX and PASS? > > Yes, in all modes: XDP_TX, XDP_PASS and XDP_REDIRECT to XSK (xdpsock). > > > No, I get correct packet data for AF_XDP zero-copy XDP_REDIRECT, > > XDP_PASS, and XDP_TX for Intel. > > Hmm, weird - with the new API I expected the same behavior on all > drivers. Thanks for the information, I'll know that I need to look in > mlx5 code to find the issue. > All zeros hints that you're probably putting in the wrong DMA address somewhere. > >> For performance, I got +1.0..+1.2 Mpps on RX. TX performance got > >> better after Björn inlined the relevant UMEM functions, however, there > >> is still a slight decrease compared to the old code. I'll try to find > >> the possible reason, but the good thing is that it's not significant > >> anymore. > >> > > > > Ok, so for Rx mlx5 it's the same as for i40e. Good! :-) > > > > How much decrease on Tx? > > ~0.8 Mpps (was 3.1 before you inlined the functions). > Thanks. Still a bit much. What does perf say? Björn
