...
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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