Re: [Bloat] CAKE in openwrt high CPU
Mikael Abrahamsson via Bloat writes: > Hi, > > I migrated to an APU2 (https://www.pcengines.ch/apu2.htm) as residential > router, from my previous WRT1200AC (marvell armada 385). > > I was running OpenWrt 18.06 on that one, now I am running latest 19.07.3 > on the APU2. > > Before I had 500/100 and I had to use FQ_CODEL because CAKE took too much > CPU to be able to do 500/100 on the WRT1200AC. Now I upgraded to 1000/1000 > and tried it again, and even the APU2 can only do CAKE up to ~300 > megabit/s. With FQ_CODEL I get full speed (configure 900/900 in SQM in > OpenWrt). > > Looking in top, I see sirq% sitting at 50% pegged. This is typical what I > see when CPU based forwarding is maxed out. From my recollection of > running CAKE on earlier versions of openwrt (17.x) I don't remember CAKE > using more CPU than FQ_CODEL. > > Anyone know what's up? I'm fine running FQ_CODEL, it solves any > bufferbloat but... I thought CAKE supposedly should use less CPU, not > more? Hmm, you say CAKE and FQ-Codel - so you're not enabling the shaper (that would be FQ-CoDel+HTB)? An exact config might be useful (or just the output of tc -s qdisc). If you are indeed not shaping, maybe you're hitting the issue fixed by this commit? https://github.com/dtaht/sch_cake/commit/3152477235c934022049fcddc063c45d37ec10e6n -Toke ___ Bloat mailing list Bloat@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/bloat
Re: [Bloat] CAKE in openwrt high CPU
On Mon, 31 Aug 2020, Toke Høiland-Jørgensen wrote: Hmm, you say CAKE and FQ-Codel - so you're not enabling the shaper (that would be FQ-CoDel+HTB)? An exact config might be useful (or just the output of tc -s qdisc). Yeah, I guess I'm also using HTB to get the 900 megabit/s SQM is looking for. If I only use FQ_CODEL to get interface speeds my performance is fine. If you are indeed not shaping, maybe you're hitting the issue fixed by this commit? https://github.com/dtaht/sch_cake/commit/3152477235c934022049fcddc063c45d37ec10e6n I enabled it just now to get the config. qdisc cake 8030: dev eth0 root refcnt 9 bandwidth 900Mbit besteffort triple-isolate nonat nowash no-ack-filter split-gso rtt 100.0ms raw overhead 0 Sent 4346128 bytes 11681 pkt (dropped 0, overlimits 1004 requeues 17) backlog 0b 0p requeues 17 memory used: 33328b of 15140Kb capacity estimate: 900Mbit min/max network layer size: 42 /1514 min/max overhead-adjusted size: 42 /1514 average network hdr offset: 14 Tin 0 thresh900Mbit target 5.0ms interval 100.0ms pk_delay 18us av_delay 6us sp_delay 4us backlog0b pkts11681 bytes 4346128 way_inds 30 way_miss 735 way_cols0 drops 0 marks 0 ack_drop0 sp_flows3 bk_flows1 un_flows0 max_len 22710 quantum 1514 qdisc ingress : dev eth0 parent :fff1 Sent 4716199 bytes 10592 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 ... qdisc cake 8031: dev ifb4eth0 root refcnt 2 bandwidth 900Mbit besteffort triple-isolate nonat nowash no-ack-filter split-gso rtt 100.0ms raw overhead 0 Sent 4946683 bytes 10592 pkt (dropped 0, overlimits 492 requeues 0) backlog 0b 0p requeues 0 memory used: 35Kb of 15140Kb capacity estimate: 900Mbit min/max network layer size: 60 /1514 min/max overhead-adjusted size: 60 /1514 average network hdr offset: 14 Tin 0 thresh900Mbit target 5.0ms interval 100.0ms pk_delay 19us av_delay 6us sp_delay 4us backlog0b pkts10592 bytes 4946683 way_inds 33 way_miss 969 way_cols0 drops 0 marks 0 ack_drop0 sp_flows2 bk_flows1 un_flows0 max_len 21196 quantum 1514 -- Mikael Abrahamssonemail: swm...@swm.pp.se___ Bloat mailing list Bloat@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/bloat
Re: [Bloat] CAKE in openwrt high CPU
Mikael Abrahamsson writes: > On Mon, 31 Aug 2020, Toke Høiland-Jørgensen wrote: > >> Hmm, you say CAKE and FQ-Codel - so you're not enabling the shaper (that >> would be FQ-CoDel+HTB)? An exact config might be useful (or just the >> output of tc -s qdisc). > > Yeah, I guess I'm also using HTB to get the 900 megabit/s SQM is looking > for. Ah, right, makes more sense :) > If I only use FQ_CODEL to get interface speeds my performance is fine. And what about when you're running CAKE in 'unlimited' mode? >> If you are indeed not shaping, maybe you're hitting the issue fixed by this >> commit? >> >> https://github.com/dtaht/sch_cake/commit/3152477235c934022049fcddc063c45d37ec10e6n > > I enabled it just now to get the config. > > qdisc cake 8030: dev eth0 root refcnt 9 bandwidth 900Mbit besteffort > triple-isolate nonat nowash no-ack-filter split-gso rtt 100.0ms raw > overhead 0 Hmm, right, you could try no-split-gso as an option as well; you're pretty close to the point where we turn it off by default, and you're getting pretty large packets (max_len), so your performance may be suffering from the splitting... -Toke ___ Bloat mailing list Bloat@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/bloat
