ZaggeOdoes anyone know what is the reason that xhci_hcd is compiled into the kernel and is not as a module10:27
mlankhorstwhy is it important to you?10:32
ZaggeOmlankhorst: it sometimes blocks suspend of the kernel and without being a module I can't unload to make suspend work11:29
apwZaggeO_, iirc they are compiled in else you cannot ensure that usb3 things are found by that first11:42
ZaggeO_apw: what might not be found?11:47
ZaggeO_apw: you mean during bootup or in general?12:09
apwin general12:09
apwi believe12:09
apwas i think usb2 can be loaded in responce to a device, then it will always take everything12:10
apwand so usb3 is never loaded, something like that12:10
ZaggeO_apw: it is a module on my debian machines and it works without problems there. It used to be a module on ubuntu too some releases ago12:11
apwindeed, and we changed it because it was an issue12:11
ZaggeO_since then I have the issue that my kernel sometimes no longer suspends and I need to reboot12:12
ZaggeO_and quite often I don't notice it and then the battery runs out in my backpack and when I want to use it again it is empty12:13
ZaggeO_apw: is there a different stock kernel one could use without the need to compile my own kernel?12:15
apwall our stock kernels have essentially the same config12:16
apwyou should file a bug for it, perhaps it can be fixed the suspend issue12:17
ZaggeO_apw: what kind of infos should I attach to the bug report?12:22
apweverything you said above at least12:27
hallynsforshee: hey, so tried out fuse-ext2 in a container.  Created loopback on host with ext2;  created /dev/loop0 in container;  used fuse-ext2 to mount htat.  could only mount read-only.  is that expected?  (I assume so, but am not sure based on your intro email why)13:33
sforsheehallyn: you have to supply -oforce with fuseext2 to get a rw mount13:39
sforsheehallyn: also you don't have to mess with loop if you don't want to, you can give it the name of an fs image file13:42
hallynsforshee: thanks13:43
hallynthink i'll set up some package builds in and out of that fs and see how the timings compare13:44
hallynsforshee: smoser: wow, completely naive test (timing building of lxc package exactly once) shows fuse-ext2 being faster than the container's native ext414:19
hallynI suspect ocne I start some page cache clearing that'll change,14:19
hallynbut still that completely belies smoser's argument that fuse can't be good enough :)14:20
smoseryou dont think that runnning all reads and writes through user space is faster than the kernel ?14:20
smoserif it turns out that ext4 via fuse is as fast as in-kernel ext414:21
smoserthen... um... that is really bad.14:21
smoserembarrassingly bad from the kernel ext4 perspective14:21
hallynwell i didn't compare to a *real* fs :)14:22
sforsheehallyn: that's interesting, I wonder if that will hold over multiple test runs14:26
sforsheeand if it does I'd really like to know why14:26
hallynsforshee: multiple runs, probably.  I'm guessing the data never even hit disk14:28
sforsheehallyn: it would be more apples to apples to compare ext2 in kernel to ext2 in fuse14:28
hallynso bigger runs, where i start swapping page cache, will probably get a hit14:28
hallynsforshee: i thought fuse-ext2 was actually doing ext414:28
sforsheehallyn: possible, but would it have hit disk in the normal case? I assume you were using loop.14:29
hallynYeah, using loop14:29
hallynfor the fuse fs14:29
sforsheeI don't think fuse has any driver for ext4. afaik fuseext2 supports ext2 and ext3 only14:29
hallynand no, it wouldn't have hit disk in normal case either - which is the confusing part.  14:29
hallynwell ext4 is supposed to be way faster no? :)14:29
sforsheedunno, there's definitely more complexity14:30
hallynanyway i wasnt out to do a *good* comparison this morning;  i only wanted a "this isn't completely unusable" comparison14:30
sforsheeI wonder if cking has any benchmarks for ext2 vs ext414:30
* hallyn waits for smoser to more explicitly suggest that we should all be using microkernels14:31
sforsheethough these days we're using the ext4 driver even for ext214:31
ckingsforshee, nope, but I can add them to the mix14:34
smoseryeah, its caching.14:34
smosersame reason that loop is faster than direct sometimes :)14:34
smoserthats the only thing i could figure.14:34
sforsheesmoser: but I think both cases should be cached, that's why I'm confused14:35
sforsheewe'll just wait and see what further testing shows I guess14:35
ckingsmoser, maybe metadata writes are being cached more when on the loop14:35
smoseri never understood that.14:35
sforsheecking: not more than when going through fuse I suspect14:35
smoserbut lots of times people report loop being faster than non-loop14:35
smoseroh. well. i thikn that 'fsync' doesnt actually fsync14:35
smoserthrough loop14:35
smoseris that the case ?14:36
ckingsmoser, the "advantage" of more dirty pages being cached and that extra layer may give some advantage I guess14:36
smoseri sweare i read that once. that loop devices had no fsync. but i'm clearly in over my head here :)14:36
sforsheesmoser: I don't know for sure, but I'd guess that it only syncs to the backing file and not all the way through to the disk14:37
smoserthats what i had thought.14:37
smoserwhich would mean a spinning disk would be slower when the fsync was actually forced to go to it.14:37
ckingi guess we can speculate to the cows come home, whereas using perf may tell us what's actually happening14:39
evarges: hi. Would you be able to help me find out if nested kvm is something you guys are willing to support? Running the Touch emulator on Canonistack gives me unhappy results: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/134773714:49
ubot5Launchpad bug 1347737 in linux (Ubuntu) "Kernel nested kvm support" [Undecided,New]14:49
argesev: hi, taking a look. nested KVM should work, but there are some hardware dependent issues that can occur14:49
evin that case, let me get you some more details on the VM14:50
evor do you mean the compute node's hardware?14:50
argesev: well both will be relevant14:50
evpresumably the latter :)14:50
evah, right14:50
argesev: so what is a bit confusing is that you are running on i386, but the VM is ARM arch? are you emulating?14:52
* ev bangs his head on the desk14:53
evlet's try this with x86 on x86, shall we14:53
argesev: : )14:53
xnoxwhy shan't we ;-)16:28
xeviousWill dmsetup remove flush any buffers for the device prior to removing it, or should sync be run manually? If I do need to sync manually, would `blockdev --flushbufs /dev/mapper/name` accomplish what I need? For reference, I'm concerned because of this: http://www.redhat.com/archives/dm-devel/2012-January/msg00082.html Has this been patched in recent versions of Device Mapper? If so, which version?18:23
Haukeapw: I created a bug report: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/134787919:52
ubot5Launchpad bug 1347879 in linux (Ubuntu) "Compile problem with external module and 031600rc5" [Undecided,New]19:52
rtgHauke, I'm about EOD, but I'll look at it in the AM20:08
Haukertg:  thanks20:08

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