Hello,
the supposed fragmentation turned out to be a mem leak in pkg. Please
take the latest SVN version and try again to see if you got same
results.
Thanks,
Daniel
On 03/19/07 18:52, Christian Schlatter wrote:
...
> The memory statistics indeed show a high
number of memory fragments:
>
> before 'out of memory':
>
> shmem:total_size = 536870912
> shmem:used_size = 59607040
> shmem:real_used_size = 60106488
> shmem:max_used_size = 68261536
> shmem:free_size = 476764424
> shmem:fragments = 9897
>
> after 'out of memory' (about 8000 calls per process):
>
> shmem:total_size = 536870912
> shmem:used_size = 4171160
> shmem:real_used_size = 4670744
> shmem:max_used_size = 68261536
> shmem:free_size = 532200168
> shmem:fragments = 57902
>
>>
>> You can try to compile openser with -DQM_JOIN_FREE (add it in DEFS
>> variable of Makefile.defs) and test again. Free fragments should be
>> merged and fragmentation should not occur -- processing will be
>> slower. We will try for next release to provide a better solution
>> for that.
>
> Compiling openser with -DQM_JOIN_FREE did not help. I'm not sure how
> big of a problem this fragmentation issue is.
What is the number of fragments with QM_JOIN_FREE after flooding?
The numbers included above are with QM_JOIN_FREE enabled.
> Do you think it would make sense to restart
our production openser
> instances from time to time just to make sure they're not running
> into this memory fragmentation limits?
The issue will occur only when the call rate reaches the limits of
the proxy's memory. Otherwise the chunks are reused. Transactions and
avps are rounded up to be sure there will be minimized the number of
different sizes for memory chunks. It wasn't reported too often,
maybe that's why no big attention was paid to it. This memory system
is in place since the beginning of ser. Alternative is to use sysv
shared memory, but is much slower, along with libc private memory
manager.
I've done some more testing and the same out-of-memory stuff happens
when I run sipp with 10 calls per second only. I tested with
'children=1' and I only could get through about 8200 calls (again
those 8000 calls / process). And this is with QM_JOIN_FREE enabled.
Memory statistics:
before:
shmem:total_size = 536870912
shmem:used_size = 2311976
shmem:real_used_size = 2335720
shmem:max_used_size = 2465816
shmem:free_size = 534535192
shmem:fragments = 183
after:
shmem:total_size = 536870912
shmem:used_size = 1853472
shmem:real_used_size = 1877224
shmem:max_used_size = 2465816
shmem:free_size = 534993688
shmem:fragments = 547
So I'm not sure if this is really a fragmentation issue. 10 cps surely
doesn't reach the proxy's memory.
Thoughts?
Christian
Cheers,
Daniel
>
> thanks,
> Christian
>
>>
>> Cheers,
>> Daniel
>>
>> On 03/18/07 01:21, Christian Schlatter wrote:
>>> Christian Schlatter wrote:
>>> ...
>>>>
>>>> I always had 768MB shared memory configured though, so I still
>>>> can't explain the memory allocation errors I got. Some more test
>>>> runs revealed that I only get these errors when using a more
>>>> production oriented config that loads more modules than the one
>>>> posted in my earlier email. I now try to figure out what exactly
>>>> causes these memory allocation errors that happen reproducibly
>>>> after about 220s at 400 cps.
>>>
>>> I think I found the cause for the memory allocation errors. As
>>> soon as I include an AVP write operation in the routing script, I
>>> get 'out of memory' messages after a certain number of calls
>>> generated with sipp.
>>>
>>> The routing script to reproduce this behavior looks like (full
>>> config available at
>>>
http://www.unc.edu/~cschlatt/openser/openser.cfg):
>>>
>>> route{
>>> $avp(s:ct) = $ct; # commenting this line solves
>>> # the memory problem
>>>
>>> if (!method=="REGISTER") record_route();
>>> if (loose_route()) route(1);
>>>
>>> if (uri==myself) rewritehost("xx.xx.xx.xx");
>>> route(1);
>>> }
>>>
>>> route[1] {
>>> if (!t_relay()) sl_reply_error();
>>> exit;
>>> }
>>>
>>> An example log file showing the 'out of memory' messages is
>>> available at
http://www.unc.edu/~cschlatt/openser/openser.log .
>>>
>>> Some observations:
>>>
>>> - The 'out of memory' messages always appear after about 8000 test
>>> calls per worker process. One call consists of two SIP
>>> transactions and six end-to-end SIP messages. An openser with 8
>>> children handles about 64'000 calls, whereas 4 children only
>>> handle about 32'000 calls. The sipp call rate doesn't matter, only
>>> number of calls.
>>>
>>> - The 8000 calls per worker process are independent from the
>>> amount of shared memory available. Running openser with -m 128 or
>>> -m 768 does not make a difference.
>>>
>>> - The more AVP writes are done in the script, the less calls go
>>> through. It looks like each AVP write is leaking memory (unnoticed
>>> by the memory statistics).
>>>
>>> - The fifo memory statistics do not reflect the 'out of memory'
>>> syslog messages. Even if openser does not route a single SIP
>>> message because of memory issues, the statistics still show a lot
>>> of 'free' memory.
>>>
>>>
>>> All tests were done with openser SVN 1.2 branch on Ubuntu dapper
>>> x86. I think the same is true for 1.1 version but I haven't tested
>>> that yet.
>>>
>>>
>>> Christian
>>>
>
>
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