25 Dec
2022
25 Dec
'22
3:37 p.m.
Hi Pau and Harald,
So sgsnemu is passing use_kernel=false, which makes
the lib skip gtp-kernel functions
That is nice, I can play with that part quite nicely and take a look
how the GGSN handles the switch between kernel and non-kernel GTP.
Thanks for that!
@Harald:
In gtpnl.h there is
int gtp_dev_create()
and
int gtp_dev_create_sgsn()
So it seems there is a different dev create for the SGSN mode. And in
the later one the role is set to "GTP_ROLE_SGSN"
int gtp_dev_create(int dest_ns, const char *gtp_ifname, int fd0, int fd1)
{
return _gtp_dev_create(dest_ns, gtp_ifname, fd0, fd1, GTP_ROLE_GGSN);
}
EXPORT_SYMBOL(gtp_dev_create);
int gtp_dev_create_sgsn(int dest_ns, const char *gtp_ifname, int fd0, int fd1)
{
return _gtp_dev_create(dest_ns, gtp_ifname, fd0, fd1, GTP_ROLE_SGSN);
}
EXPORT_SYMBOL(gtp_dev_create_sgsn);
I just need to find the relevant part is sgsn-emu to see where these
parts are invoked so I can make the modifications.
Regards,
Csaba
<openbsc-request(a)lists.osmocom.org> ezt írta (időpont: 2022. dec. 24.,
Szo, 13:00):
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Today's Topics:
1. Re: SGSNemu performance (Pau Espin Pedrol)
2. Re: SGSNemu performance (Harald Welte)
----------------------------------------------------------------------
Message: 1
Date: Fri, 23 Dec 2022 18:38:55 +0100
From: Pau Espin Pedrol <pespin(a)sysmocom.de>
Subject: Re: SGSNemu performance
To: Sipos Csaba <dchardware(a)gmail.com>om>,
"openbsc-request(a)lists.osmocom.org" <openbsc(a)lists.osmocom.org>rg>,
laforge(a)osmocom.org
Message-ID: <782d5c68-0393-e63a-ddbd-a78ca04256e0(a)sysmocom.de>
Content-Type: text/plain; charset=UTF-8; format=flowed
Hi Csaba,
On 12/22/22 15:00, Sipos Csaba wrote:
Dear Harald,
Sorry to spam the openbsc list with this, but if you (or someone) can
confirm if the Sgsn-emu part of Osmo-GGSN utilizing the kernel GTP
module or not, that would be lovely.
sgsnemu is not using the kernel module, only osmo-ggsn has support for
it so far.
See osmo-ggsn.git/./sgsnemu/sgsnemu.c line 1905 calling:
"""
if (tun_new((struct tun_t **)&tun, options.tun_dev_name, false, -1, -1))
"""
See tun_new() function used by both osmo-ggsn and sgsnemu:
"""
int tun_new(struct tun_t **tun, const char *dev_name, bool use_kernel,
int fd0, int fd1u) {
"""
So sgsnemu is passing use_kernel=false, which makes the lib skip
gtp-kernel functions like gtp_kernel_create().
FYI, I was not able to pass more than 280Mbit and the sgsn-emu process
was maxing out a single core. Based on this I suspect that it does not
use the kernel GTP module. I have seen some commits that indicates
preparation work for this feature, but it is unclear at least to me,
if this was finished or not. In the Osmo-GGSN.cfg example config I can
see the config option for kernel GTP, but not in the sgsn-emu.cfg
example.
You could try passing use_kernel=true to tun_new(), and see how far you
can get. Patches welcome.
Regards,
Pau
--
- Pau Espin Pedrol <pespin(a)sysmocom.de> http://www.sysmocom.de/
=======================================================================
* sysmocom - systems for mobile communications GmbH
* Alt-Moabit 93
* 10559 Berlin, Germany
* Sitz / Registered office: Berlin, HRB 134158 B
* Geschaeftsfuehrer / Managing Director: Harald Welte
------------------------------
Message: 2
Date: Fri, 23 Dec 2022 18:47:57 +0100
From: Harald Welte <laforge(a)gnumonks.org>
Subject: Re: SGSNemu performance
To: Pau Espin Pedrol <pespin(a)sysmocom.de>
Cc: Sipos Csaba <dchardware(a)gmail.com>om>,
"openbsc-request(a)lists.osmocom.org" <openbsc(a)lists.osmocom.org>
Message-ID: <Y6XpzZoYYdVxYKdb@nataraja>
Content-Type: text/plain; charset=us-ascii
Hi Csaba and Pau,
On Fri, Dec 23, 2022 at 06:38:55PM +0100, Pau Espin Pedrol wrote:
You could try passing use_kernel=true to
tun_new(), and see how far you can
get. Patches welcome.
The GTP kernel module needs to be told if it operates in SGSN or GGSN mode.
grep for GTP_ROLE_SGSN in libgtpnl. I don't know all of the related functions
off my head, but on the SGSN side you need to make sure to initialize the kernel
GTP with GTP_ROLE_SGSN instead of GTP_ROLE_GGSN.
--
- Harald Welte <laforge(a)gnumonks.org> https://laforge.gnumonks.org/
============================================================================
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