On Sun, Aug 26, 2018 at 6:33 PM Rosen Penev <ros...@gmail.com> wrote: > > On Sun, Aug 26, 2018 at 6:20 PM Dave Taht <dave.t...@gmail.com> wrote: > > > > On Sun, Aug 26, 2018 at 5:55 PM Rosen Penev <ros...@gmail.com> wrote: > > > > > > On Sun, Aug 26, 2018 at 2:09 PM Dave Taht <dave.t...@gmail.com> wrote: > > > > > > > > On Sun, Aug 26, 2018 at 1:58 PM Rosen Penev <ros...@gmail.com> wrote: > > > > > > > > > > On Sun, Aug 26, 2018 at 11:44 AM Mikael Abrahamsson > > > > > <swm...@swm.pp.se> wrote: > > > > > > > > > > > > On Sat, 25 Aug 2018, Dave Taht wrote: > > > > > > > > > > > > > The expressobin is a Marvell Armada "3700LP (88F3720) dual core > > > > > > > ARM > > > > > > > Cortex A53 processor up to 1.2GHz" - how does that compare? I have > > > > > > > plenty of ath10k and ath9k pcmcia cards.... > > > > > > > > > > > > I have one of these, incl wifi. Right now the drivers are not in > > > > > > great > > > > > > shape, but they're being worked on. My espressobin has worse > > > > > > performance > > > > > > than on its wired ports than my WRT1200AC (Armada 385). > > > > > If as you mentioned earlier that ethernet performance is limited by > > > > > interrupts, then this commit is kind of depressing: > > > > > > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/drivers/net/ethernet/marvell/mvneta.c?h=next-20180824&id=0f5c6c30a0f8c629b92ecdaef61b315c43fde10a > > > > > > > > I was on that thread. It was broken before entirely. As for the single > > > > interrupt on this chip variant - believe it or not, I'm not huge on > > > > lots of different interrupts for everything. I'd like it if we had > > > > more than an rx or tx interrupt > > > > in general, I'd love it if we had a programmable "tx is almost done" > > > > interrupt that you could tune to the > > > > interrupt latency... and it's complicated and costs wires to have lots > > > > of different interrupt types... and (fantasizing again) I'd love it if > > > > we had a scratchpad or dedicated memory to store interrupt handlers in > > > > rather than relying on cache.... > > > > > > > > I'd looked deeply into improving this driver once upon a time, and > > > > wanted to rip the software gro out of it, > > > > in particular, and not defer things as much, trying things like NAPI > > > > of 16 and measuring where time was spent. The copy to memory is > > > > expensive, and then it defers further work. > > > > > > > > Less code, particularly near interrupt time, is better than a lot. > > > > adding XMIT_MORE to the ar71xx driver (which hurt it badly) is one > > > > example. > > > I've been looking a lot at ag71xx. The driver has so much low hanging > > > fruit. Unfortunately I lack the knowledge to fix most of it. > > > > > > This patch for example gives me a ~20-30mbps improvement in iperf > > > tests: https://pastebin.com/ZExWjXQZ > > > > cool! that driver as widely used as it is has never had enough eyeballs on > > it. > No. Definitely not enough. > > > > Have you put that patch in front of the openwrt folk? I note that that > > driver didn't > > used to live in that part of the tree - have they finally moved over? > Yeah I did. Felix rejected it on the grounds that he didn't understand > it. So I've just been keeping it in my tree. The patch itself comes > from an old SDK by Qualcomm.
Hmm. By eyeball I can't see how it could speed up things that much either. :) But I used to be willig to bnchmark. not thi month though > > > > > > > > > > > > It's kind of unfortunate given how much atheros hardware is out there. > > > > > > > > Given something *cool* now landing ( skb list batching, see lwn ) it > > > > would be worthwhile to revisit this. I don't care if I get more > > > > interrupts/sec (particularly on a multicore) if we could drain the rx > > > > ring over smaller intervals... > > > > > > > > but that's me, I'm all about the latency. :) Nobody's willing to rip > > > > the latency out of stuff, they'd rather add features. It's really hard > > > > to correctly measure interrupt latency regardless. > > > > > > > > > > > > > > > > > > > > I have talked to people who say the drivers are being worked on > > > > > > though... > > > > > > If you have input, Kaloz is probably a great person to take that > > > > > > input. I > > > > > > know other people working on Marvell drivers as well. > > > > > > > > > > > > -- > > > > > > Mikael Abrahamsson email: swm...@swm.pp.se > > > > > > _______________________________________________ > > > > > > Bloat mailing list > > > > > > Bloat@lists.bufferbloat.net > > > > > > https://lists.bufferbloat.net/listinfo/bloat > > > > > > > > > > > > > > > > -- > > > > > > > > Dave Täht > > > > CEO, TekLibre, LLC > > > > http://www.teklibre.com > > > > Tel: 1-669-226-2619 > > > > > > > > -- > > > > Dave Täht > > CEO, TekLibre, LLC > > http://www.teklibre.com > > Tel: 1-669-226-2619 -- Dave Täht CEO, TekLibre, LLC http://www.teklibre.com Tel: 1-669-226-2619 _______________________________________________ Bloat mailing list Bloat@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/bloat