Messages in this thread | | | From | Shenwei Wang <> | Subject | RE: [EXT] Re: [PATCH 1/1] net: fec: add initial XDP support | Date | Mon, 3 Oct 2022 12:49:51 +0000 |
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Hi Jesper,
> >> On mvneta driver/platform we saw huge speedup replacing: > >> > >> page_pool_release_page(rxq->page_pool, page); with > >> skb_mark_for_recycle(skb); > >>
After replacing the page_pool_release_page with the skb_mark_for_recycle, I found something confused me a little in the testing result. I tested with the sample app of "xdpsock" under two modes: 1. Native (xdpsock -i eth0). 2. Skb-mode (xdpsock -S -i eth0). The following are the testing result: With page_pool_release_page (pps) With skb_mark_for_recycle (pps)
SKB-Mode 90K 200K Native 190K 190K
The skb_mark_for_recycle solution boosted the performance of SKB-Mode to 200K+ PPS. That is even higher than the performance of Native solution. Is this result reasonable? Do you have any clue why the SKB-Mode performance can go higher than that of Native one?
Thanks, Shenwei
> -----Original Message----- > From: Jesper Dangaard Brouer <jbrouer@redhat.com> > Sent: Thursday, September 29, 2022 1:55 PM > To: Shenwei Wang <shenwei.wang@nxp.com>; Jesper Dangaard Brouer > <jbrouer@redhat.com>; Andrew Lunn <andrew@lunn.ch> > Cc: brouer@redhat.com; Joakim Zhang <qiangqing.zhang@nxp.com>; David S. > Miller <davem@davemloft.net>; Eric Dumazet <edumazet@google.com>; Jakub > Kicinski <kuba@kernel.org>; Paolo Abeni <pabeni@redhat.com>; Alexei > Starovoitov <ast@kernel.org>; Daniel Borkmann <daniel@iogearbox.net>; > Jesper Dangaard Brouer <hawk@kernel.org>; John Fastabend > <john.fastabend@gmail.com>; netdev@vger.kernel.org; linux- > kernel@vger.kernel.org; imx@lists.linux.dev > Subject: Re: [EXT] Re: [PATCH 1/1] net: fec: add initial XDP support > > Caution: EXT Email > > On 29/09/2022 17.52, Shenwei Wang wrote: > > > >> From: Jesper Dangaard Brouer <jbrouer@redhat.com> > >> > >> On 29/09/2022 15.26, Shenwei Wang wrote: > >>> > >>>> From: Andrew Lunn <andrew@lunn.ch> > >>>> Sent: Thursday, September 29, 2022 8:23 AM > >> [...] > >>>> > >>>>> I actually did some compare testing regarding the page pool for > >>>>> normal traffic. So far I don't see significant improvement in the > >>>>> current implementation. The performance for large packets improves > >>>>> a little, and the performance for small packets get a little worse. > >>>> > >>>> What hardware was this for? imx51? imx6? imx7 Vybrid? These all use the > FEC. > >>> > >>> I tested on imx8qxp platform. It is ARM64. > >> > >> On mvneta driver/platform we saw huge speedup replacing: > >> > >> page_pool_release_page(rxq->page_pool, page); with > >> skb_mark_for_recycle(skb); > >> > >> As I mentioned: Today page_pool have SKB recycle support (you might > >> have looked at drivers that didn't utilize this yet), thus you don't > >> need to release the page (page_pool_release_page) here. Instead you > >> could simply mark the SKB for recycling, unless driver does some page refcnt > tricks I didn't notice. > >> > >> On the mvneta driver/platform the DMA unmap (in > >> page_pool_release_page) was very expensive. This imx8qxp platform > >> might have faster DMA unmap in case is it cache-coherent. > >> > >> I would be very interested in knowing if skb_mark_for_recycle() helps > >> on this platform, for normal network stack performance. > >> > > > > Did a quick compare testing for the following 3 scenarios: > > Thanks for doing this! :-) > > > 1. original implementation > > > > shenwei@5810:~$ iperf -c 10.81.16.245 -w 2m -i 1 > > ------------------------------------------------------------ > > Client connecting to 10.81.16.245, TCP port 5001 TCP window size: 416 > > KByte (WARNING: requested 1.91 MByte) > > ------------------------------------------------------------ > > [ 1] local 10.81.17.20 port 49154 connected with 10.81.16.245 port 5001 > > [ ID] Interval Transfer Bandwidth > > [ 1] 0.0000-1.0000 sec 104 MBytes 868 Mbits/sec > > [ 1] 1.0000-2.0000 sec 105 MBytes 878 Mbits/sec > > [ 1] 2.0000-3.0000 sec 105 MBytes 881 Mbits/sec > > [ 1] 3.0000-4.0000 sec 105 MBytes 879 Mbits/sec > > [ 1] 4.0000-5.0000 sec 105 MBytes 878 Mbits/sec > > [ 1] 5.0000-6.0000 sec 105 MBytes 878 Mbits/sec > > [ 1] 6.0000-7.0000 sec 104 MBytes 875 Mbits/sec > > [ 1] 7.0000-8.0000 sec 104 MBytes 875 Mbits/sec > > [ 1] 8.0000-9.0000 sec 104 MBytes 873 Mbits/sec > > [ 1] 9.0000-10.0000 sec 104 MBytes 875 Mbits/sec > > [ 1] 0.0000-10.0073 sec 1.02 GBytes 875 Mbits/sec > > > > 2. Page pool with page_pool_release_page > > > > shenwei@5810:~$ iperf -c 10.81.16.245 -w 2m -i 1 > > ------------------------------------------------------------ > > Client connecting to 10.81.16.245, TCP port 5001 TCP window size: 416 > > KByte (WARNING: requested 1.91 MByte) > > ------------------------------------------------------------ > > [ 1] local 10.81.17.20 port 35924 connected with 10.81.16.245 port 5001 > > [ ID] Interval Transfer Bandwidth > > [ 1] 0.0000-1.0000 sec 101 MBytes 849 Mbits/sec > > [ 1] 1.0000-2.0000 sec 102 MBytes 860 Mbits/sec > > [ 1] 2.0000-3.0000 sec 102 MBytes 860 Mbits/sec > > [ 1] 3.0000-4.0000 sec 102 MBytes 859 Mbits/sec > > [ 1] 4.0000-5.0000 sec 103 MBytes 863 Mbits/sec > > [ 1] 5.0000-6.0000 sec 103 MBytes 864 Mbits/sec > > [ 1] 6.0000-7.0000 sec 103 MBytes 863 Mbits/sec > > [ 1] 7.0000-8.0000 sec 103 MBytes 865 Mbits/sec > > [ 1] 8.0000-9.0000 sec 103 MBytes 862 Mbits/sec > > [ 1] 9.0000-10.0000 sec 102 MBytes 856 Mbits/sec > > [ 1] 0.0000-10.0246 sec 1.00 GBytes 858 Mbits/sec > > > > > > 3. page pool with skb_mark_for_recycle > > > > shenwei@5810:~$ iperf -c 10.81.16.245 -w 2m -i 1 > > ------------------------------------------------------------ > > Client connecting to 10.81.16.245, TCP port 5001 TCP window size: 416 > > KByte (WARNING: requested 1.91 MByte) > > ------------------------------------------------------------ > > [ 1] local 10.81.17.20 port 42724 connected with 10.81.16.245 port 5001 > > [ ID] Interval Transfer Bandwidth > > [ 1] 0.0000-1.0000 sec 111 MBytes 931 Mbits/sec > > [ 1] 1.0000-2.0000 sec 112 MBytes 935 Mbits/sec > > [ 1] 2.0000-3.0000 sec 111 MBytes 934 Mbits/sec > > [ 1] 3.0000-4.0000 sec 111 MBytes 934 Mbits/sec > > [ 1] 4.0000-5.0000 sec 111 MBytes 934 Mbits/sec > > [ 1] 5.0000-6.0000 sec 112 MBytes 935 Mbits/sec > > [ 1] 6.0000-7.0000 sec 111 MBytes 934 Mbits/sec > > [ 1] 7.0000-8.0000 sec 111 MBytes 933 Mbits/sec > > [ 1] 8.0000-9.0000 sec 112 MBytes 935 Mbits/sec > > [ 1] 9.0000-10.0000 sec 111 MBytes 933 Mbits/sec > > [ 1] 0.0000-10.0069 sec 1.09 GBytes 934 Mbits/sec > > This is a very significant performance improvement (page pool with > skb_mark_for_recycle). This is very close to the max goodput for a 1Gbit/s link. > > > > For small packet size (64 bytes), all three cases have almost the same result: > > > > To me this indicate, that the DMA map/unmap operations on this platform are > indeed more expensive on larger packets. Given this is what page_pool does, > keeping the DMA mapping intact when recycling. > > Driver still need DMA-sync, although I notice you set page_pool feature flag > PP_FLAG_DMA_SYNC_DEV, this is good as page_pool will try to reduce sync size > where possible. E.g. in this SKB case will reduce the DMA-sync to the > max_len=FEC_ENET_RX_FRSIZE which should also help on performance. > > > > shenwei@5810:~$ iperf -c 10.81.16.245 -w 2m -i 1 -l 64 > > ------------------------------------------------------------ > > Client connecting to 10.81.16.245, TCP port 5001 TCP window size: 416 > > KByte (WARNING: requested 1.91 MByte) > > ------------------------------------------------------------ > > [ 1] local 10.81.17.20 port 58204 connected with 10.81.16.245 port 5001 > > [ ID] Interval Transfer Bandwidth > > [ 1] 0.0000-1.0000 sec 36.9 MBytes 309 Mbits/sec > > [ 1] 1.0000-2.0000 sec 36.6 MBytes 307 Mbits/sec > > [ 1] 2.0000-3.0000 sec 36.6 MBytes 307 Mbits/sec > > [ 1] 3.0000-4.0000 sec 36.5 MBytes 307 Mbits/sec > > [ 1] 4.0000-5.0000 sec 37.1 MBytes 311 Mbits/sec > > [ 1] 5.0000-6.0000 sec 37.2 MBytes 312 Mbits/sec > > [ 1] 6.0000-7.0000 sec 37.1 MBytes 311 Mbits/sec > > [ 1] 7.0000-8.0000 sec 37.1 MBytes 311 Mbits/sec > > [ 1] 8.0000-9.0000 sec 37.1 MBytes 312 Mbits/sec > > [ 1] 9.0000-10.0000 sec 37.2 MBytes 312 Mbits/sec > > [ 1] 0.0000-10.0097 sec 369 MBytes 310 Mbits/sec > > > > Regards, > > Shenwei > > > > > >>>> By small packets, do you mean those under the copybreak limit? > >>>> > >>>> Please provide some benchmark numbers with your next patchset. > >>> > >>> Yes, the packet size is 64 bytes and it is under the copybreak limit. > >>> As the impact is not significant, I would prefer to remove the > >>> copybreak logic. > >> > >> +1 to removing this logic if possible, due to maintenance cost. > >> > >> --Jesper > >
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