[ovs-discuss] ovs-vswitchd process huge memory consumption
blp at ovn.org
Tue Mar 5 21:08:01 UTC 2019
Starting from 0x30, this looks like a "minimatch" data structure, which
is a kind of compressed bitwise match against a flow.
00000030: 0000 0000 0000 4014 0000 0000 0000 0000
00000040: 0000 0000 0000 0000 fa16 3e2b c5d5 0000 0000 0022 0000 0000
00000058: 0000 0000 0000 4014 0000 0000 0000 0000
00000068: 0000 0000 ffff ffff ffff ffff ffff 0000 0000 0fff 0000 0000
I think this corresponds to a flow of this form:
Is that at all meaningful? Does it match anything that appears in the
OpenFlow flow table?
Are you using the kernel or DPDK datapath?
On Tue, Mar 05, 2019 at 08:42:14PM +0400, Oleg Bondarev wrote:
> thanks for your help!
> On Tue, Mar 5, 2019 at 7:26 PM Ben Pfaff <blp at ovn.org> wrote:
> > You're talking about the email where you dumped out a repeating sequence
> > from some blocks? That might be the root of the problem, if you can
> > provide some more context. I didn't see from the message where you
> > found the sequence (was it just at the beginning of each of the 4 MB
> > blocks you reported separately, or somewhere else), how many copies of
> > it, or if you were able to figure out how long each of the blocks was.
> > If you can provide that information I might be able to learn some
> > things.
> Yes, those were beginnings of 0x4000000 size blocks reported by the script.
> I also checked 0x8000000 blocks reported and the content is the same.
> Examples of how those blocks end:
> - https://pastebin.com/D9M6T2BA
> - https://pastebin.com/gNT7XEGn
> - https://pastebin.com/fqy4XDbN
> So basically contents of the blocks are sequences of:
> *00000020: 0000 0000 0000 0000 6500 0000 0000 0000 ........e.......*
> *00000030: 0000 0000 0000 4014 0000 0000 0000 0000 ...... at .........*
> *00000040: 0000 0000 0000 0000 fa16 3e2b c5d5 0000 ..........>+....*
> *00000050: 0000 0022 0000 0000 0000 0000 0000 4014 ...".......... at .*
> *00000060: 0000 0000 0000 0000 0000 0000 ffff ffff ................*
> *00000070: ffff ffff ffff 0000 0000 0fff 0000 0000 ................*
> following each other and sometimes separated by sequences like this:
> *00001040: 6861 6e64 6c65 7232 3537 0000 0000 0000 handler257......*
> I ran the scripts against several core dumps of several compute nodes with
> the issue and
> the picture is pretty much the same: 0x4000000 blocks and less 0x8000000
> I checked the core dump from a compute node where OVS memory consumption
> was ok:
> no such block sizes reported.
> > On Tue, Mar 05, 2019 at 09:07:55AM +0400, Oleg Bondarev wrote:
> > > Hi Ben,
> > >
> > > I didn't have a chance to debug the scripts yet, but just in case you
> > > missed my last email with examples of repeatable blocks
> > > and sequences - do you think we still need to analyze further, will the
> > > scripts tell more about the heap?
> > >
> > > Thanks,
> > > Oleg
> > >
> > > On Thu, Feb 28, 2019 at 10:14 PM Ben Pfaff <blp at ovn.org> wrote:
> > >
> > > > On Tue, Feb 26, 2019 at 01:41:45PM +0400, Oleg Bondarev wrote:
> > > > > Hi,
> > > > >
> > > > > thanks for the scripts, so here's the output for a 24G core dump:
> > > > > https://pastebin.com/hWa3R9Fx
> > > > > there's 271 entries of 4MB - does it seem something we should take a
> > > > closer
> > > > > look at?
> > > >
> > > > I think that this output really just indicates that the script failed.
> > > > It analyzed a lot of regions but didn't output anything useful. If it
> > > > had worked properly, it would have told us a lot about data blocks that
> > > > had been allocated and freed.
> > > >
> > > > The next step would have to be to debug the script. It definitely
> > > > worked for me before, because I have fixed at least 3 or 4 bugs based
> > on
> > > > it, but it also definitely is a quick hack and not something that I can
> > > > stand behind. I'm not sure how to debug it at a distance. It has a
> > > > large comment that describes what it's trying to do. Maybe that would
> > > > help you, if you want to try to debug it yourself. I guess it's also
> > > > possible that glibc has changed its malloc implementation; if so, then
> > > > it would probably be necessary to start over and build a new script.
> > > >
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