On Sun, Apr 9, 2017 at 9:31 AM, John Spray <jspray@xxxxxxxxxx> wrote:
On Sun, Apr 9, 2017 at 12:48 AM, Kyle Drake <kyle@xxxxxxxxxxxxx> wrote:
> Pretty much says it all. 1GB test file copy to local:
>
> $ time cp /mnt/ceph-kernel-driver-test/test.img . What does "fresh" mean in this context? i.e. what did you do in
>
> real 2m50.063s
> user 0m0.000s
> sys 0m9.000s
>
> $ time cp /mnt/ceph-fuse-test/test.img .
>
> real 0m3.648s
> user 0m0.000s
> sys 0m1.872s
>
> Yikes. The kernel driver averages ~5MB and the fuse driver averages
> ~150MBish? Something crazy is happening here. It's not caching, I ran both
> tests fresh.
between runs to reset it? Have you tried running your procedure in
the reverse order (i.e. is the kernel client still slow when you're
running it after the fuse client)?
I rebooted the machine and ran the same test.
I just repeated the exercise by creating two completely different test files, one for each driver, and got the same results.
The FUSE driver has never under any circumstances been as slow, though when I feed a lot of activity into it at once, it tends to get stuck on something and hang for a while, so it's not a solution for me unfortunately.
> Ubuntu 16.04.2, 4.4.0-72-generic, ceph-fuse 10.2.6-1xenial, ceph-fs-common
> 10.2.6-0ubuntu0.16.04.1 (I also tried the 16.04.2 one, same issue).
I don't know of any issues in the older kernel that you're running,
but you should be aware that 4.4 is over a year old and as far as I
know there is no backporting of cephfs stuff to the Ubuntu kernel, so
you're not getting the latest fixes.
That could be related, but Ubuntu 16.04 is going to be around for a long time, so this is probably something that needs to get addressed (unless I'm literally the only person on the planet experiencing this bug, as it seems to be right now). I don't know how to get on a newer kernel than that (without potentially wrecking the distro).
I was actually about to try 14.04 to see if it does the same thing. If it works I'll post an update.
-Kyle
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