Asterisk incontinence, leaking all that memory…

During the last week i spent quite some time testing several Asterisk versions in terms of memory usage. My test scenario involves an Asterisk server which receives SIP calls from a call generator (based on sofia-sip) and runs a very simple dialplan:

exten => _+.,1,Wait(15)
exten => _+.,n,Ringing
exten => _+.,n,Wait(10)
exten => _+.,n,Hangup

The call generator will terminate the call right after receiving the Ringing. It is configured to use 1000 SIP channels and has a caps limit of 100. With this dialplan however a caps value of about 66 can be reached. All tests were done “signalling only” without any RTP being transmitted.

This test generates about 1 to 2 MBit/s of IP traffic. Here are the results:

Asterisk 1.4.37-rc1:

Asterisk starts dropping calls and fails to respond on numerous INVITEs after processing about 3.5M calls. SIP registrations time out.

Memory consumption before the test:  virt 392m  res 12m 4396 S
Memory consumption after the test: virt 1125m res 320m 1472 S


After processing more than 5M calls Asterisk is still running fine, the memory usage is not increasing beyond 1094m res 131m 5412 S. This is a good sign for not leaking memory.

Memory consumption before the test: virt 455m  res 13m 4940 S
Memory consumption after the test: virt 637m  res 94m 5412 S

Asterisk 1.8.0

Right after the start it is using 204m of memory! That is almost 20x as much as 1.4 or 1.6 used!

After around 300k calls Asterisk segfaulted and left a 1.2 GB core file, because it could not allocate memory:

#2  0×0000000000523131 in __ast_str_helper (buf=0x7faca3d93948, max_len=8192, append=<value optimized out>,     fmt=0×552938 “Memory Allocation Failure in function %s at line %d of %s\n”, ap=0x7faca3d93900) at strings.c:72

Memory consumption before the test:  virt 717m res 204m 5700 S
Memory consumption after  the test:  none (killed by signall 11)

Executive summary (memory consumption):

Asterisk 1.4 –> BAD

Asterisk 1.6 –> GOOD

Asterisk 1.8 –> WORST