re: ath: skbuff alloc of size 1926 failed as for the ath skbuff problem, I've seen that a lot. I had put hard packet limits (~600) on fq_codel in -11 and prior that were too low and it mostly went away, but I hit tail drop behavior everywhere, instead of codel behavior. What I have now (typically 1200) may well be too high, but not as overly high as the default (10k packets). There may be another means of increasing the size of that slab pool or making it less onerous.
I would like it if codel "kicked in" earlier than it currently does. The code in ns2 is currently using half the period that the linux code is. This would control things better, or so I hope (planning on trying this as I get time) I am also considering means of artificially upscaling the drop scheduler when we get close to queue limits. See some discussions on the codel list for these issues. (sims are easier to deal with than cerowrt, too!) as for bind, it should be automagically restarted from xinetd, no need to fiddle with anything. However, since you are already under massive memory pressure, it may well fail to start up that way, too. At the moment, I've largely given up on bind on anything but a more core home gw, and am running dnsmasq on everything (3700v2, picostations, nanostations) but the 3800s. (and the ones I run it on, aren't being used for wifi right now). Lastly: Swap space won't help you on exhausting kernel limits. I'm glad you can reproduce the ath: slab problem - I can get it too at high rates using netperf over wifi. I will try a 3700v2 with and without bind to see if it's still there in 3.3.8-17. In the meantime if anyone knows how to get more allocations in that (2048? 4096?) slab by default, perhaps that will help? On Wed, Aug 15, 2012 at 10:23 AM, Sebastian Moeller <[email protected]> wrote: > Hi Dave, > > great work, as always I upgraded my production router to the latest and > greatest (since I only have one router…). And it works quite well for normal > usage… > Netalyzr reports around 2800ms seconds of uplink buffering, yet saturating > the uplink does not affect ping times to a remote target noticeably, > basically the same as for all codellized ceo versions I tested so far... > > Some notes and a question: > I noticed that even given plenty of swap space (1GB on a usb stick), using > http://broadband.mpi-sws.org/residential/ to exercise UDP stress (on the > uplink I assume) I can easily produce (I run the test from a macosx via 5GHz > wireless over 1.5 yards): > Aug 15 01:16:29 nacktmulle kern.err kernel: [175395.132812] ath: skbuff alloc > of size 1926 failed > (and plenty of those…). > What then happens is that the OOM killer will aim for bind (reasonable since > it is the largest single process) and kill it. When I try to restart bind by: > root@nacktmulle:~# /etc/rc.d/S47namedprep start > root@nacktmulle:~# /etc/rc.d/S48named restart > Stopping isc-bind > /etc/chroot/named//var/run/named/named.pid not found, trying brute force > killall: named: no process killed > Kicking isc-bind in xinetd > rndc: connect failed: 127.0.0.1#953: connection refused > And bind does not start again and the router becomes less than useful. Now I > assume I am doing something wrong, but what, if you have any idea how to > solve this short of a reboot of the router (my current method) I would be > happy to learn > > > > best regards > sebastian > > On Aug 12, 2012, at 11:08 PM, Dave Taht wrote: > >> I'm too tired to write up a full set of release notes, but I've been >> testing it all day, >> and it looks better than -10 and certainly better than -11, but I won't know >> until some more folk sit down and test it, so here it is. >> >> http://huchra.bufferbloat.net/~cero1/3.3/3.3.8-17/ >> >> fresh merge with openwrt, fix to a bind CVE, fixes for 6in4 and quagga >> routing problems, >> and a few tweaks to fq_codel setup that might make voip better. >> >> Go forth and break things! >> >> In other news: >> >> Van Jacobson gave a great talk about bufferbloat, BQL, codel, and fq_codel >> at last week's ietf meeting. Well worth watching. At the end he outlines >> the deployment problems in particular. >> >> http://recordings.conf.meetecho.com/Recordings/watch.jsp?recording=IETF84_TSVAREA&chapter=part_3 >> >> Far more interesting than this email! >> >> >> -- >> Dave Täht >> http://www.bufferbloat.net/projects/cerowrt/wiki - "3.3.8-17 is out >> with fq_codel!" >> _______________________________________________ >> Cerowrt-devel mailing list >> [email protected] >> https://lists.bufferbloat.net/listinfo/cerowrt-devel > -- Dave Täht http://www.bufferbloat.net/projects/cerowrt/wiki - "3.3.8-17 is out with fq_codel!" _______________________________________________ Cerowrt-devel mailing list [email protected] https://lists.bufferbloat.net/listinfo/cerowrt-devel
