5 Jan
2023
5 Jan
'23
4:57 p.m.
Thanks, that's educational.
I assumed the original argument was performance-related. I just wasn't sure if that
was still (sufficiently to be important) true. After all, lots of SER/OpenSER design
decisions in the early 2000s made the most sense then, like inventing own imperative
scripting language. :-)
-- Alex
On Jan 5, 2023, at 10:16 AM, Henning Westerholt
<hw(a)gilawa.com> wrote:
(adding sr-dev)
Hi Alex,
the memory allocator of glibc was not really efficient regarding the particular needs of
a SIP server (allocation of many small string objects).
That has probably improved in the last years, also system performance just got much
faster.
Other programs/tools also use their own allocators, e.g. Firefox, Rust [1] for jemalloc.
There is some (not really well tested) support in the core for using the system memory
allocator by the #define SYS_MALLOC.
It probably needs to be set in Makefile.defs, also deactivating the other PKG memory
managers, but did not looked into it right now.
Cheers,
Henning
[1] https://news.ycombinator.com/item?id=8612645
--
Henning Westerholt - https://skalatan.de/blog/
Kamailio services - https://gilawa.com
-----Original Message-----
From: Alex Balashov <abalashov(a)evaristesys.com>
Sent: Thursday, January 5, 2023 3:59 PM
To: Henning Westerholt <hw(a)gilawa.com>
Cc: Kamailio (SER) - Users Mailing List <sr-users(a)lists.kamailio.org>
Subject: Re: [SR-Users] pkg memory leak when acc module cdr_enabled
--
Alex Balashov
Principal Consultant
Evariste Systems LLC
Web: https://evaristesys.com
Tel: +1-706-510-6800
On Jan 5, 2023, at 9:40 AM, Henning Westerholt
<hw(a)gilawa.com> wrote:
Hello Alex,
there might be some performance implications by switching to system malloc. There is also
easier debugging by internal Kamailio memory manager support.
In this particular example with the leak, Kamailio would use in the end all of the system
memory, and the machine out of memory killer will then randomly processes. So the limited
memory pool also helps to protect the system against this kind of leaks.
I am in no position to assess the relative efficiencies of various memory allocators. But
it seems a bit extraordinary to suppose that a custom allocator is more efficient than the
general-purpose libc allocator, although it's obviously possible; some
application-specific optimised allocators clearly make this argument (i.e. Redis +
jemalloc).
Also, I wonder if the answer to this has changed over 20 years.
Unbounded allocation from leaks can certainly be a problem. But rendering a process
useless by running out of (much more limited) package memory (much more quickly) can also
be a problem. :-)
-- Alex
--
Alex Balashov
Principal Consultant
Evariste Systems LLC
Web: https://evaristesys.com
Tel: +1-706-510-6800