Hello!
As the first part of investigation, I would try to run BIRD with a debug
logfile on:
bird -D <filename>
Then from CLI, you issue a command "dump resources", causing a memory
allocation flush to the debug logfile.
As BIRD obviously knows about this memory, it must also know where it is
and this command dumps it. Doing this for both versions should yield
more precise information than just "show memory" and point you to the
probable cause.
If you couldn't find a cause from that, feel free to send us the memory
dumps for investigation and comparison.
Maria
On 4/14/21 12:56 PM, Macek, Dawid wrote:
Hello,
We’ve built Bird from origin/bmp branch and found out that BMP most
likely introduces memory leak.
In the experiment, the device has 4 BGP peers (see attached bird.conf).
The device is flooded with massive number of routes from each peer.
Memory-usage snapshots are taken: before flooding with routes, after
flooding with routes,
after dropping BGP sessions and waiting for routes to be removed for Linux.
The experiment was performed twice: with and without BMP configured.
Case 1: With BMP configured:
Before flooding:
BIRD memory usage
Routing tables: 20 kB
Route attributes: 6224B
Protocols:33 kB
Total: 123 kB
After flooding (about 1150000 routes in Linux):
BIRD memory usage
Routing tables:412 MB
Route attributes: 11 kB
Protocols:1473 MB
Total:1885 MB
After dropping BGP sessions and waiting for routes to be removed from
kernel:
BIRD memory usage
Routing tables:284 kB
Route attributes: 10 kB
Protocols:1018 MB
Total:1019 MB
Case 2: Same config, but without protocol bmp {…}:
Before flooding:
BIRD memory usage
Routing tables: 20 kB
Route attributes: 6224B
Protocols:26 kB
Total: 112 kB
After flooding (about 1130000 routes in Linux):
BIRD memory usage
Routing tables:381 MB
Route attributes: 11 kB
Protocols: 163 MB
Total: 544 MB
After dropping BGP sessions and waiting for routes to be removed from
kernel:
BIRD memory usage
Routing tables:284 kB
Route attributes: 10 kB
Protocols: 795 kB
Total:1153 kB
We would like to ask about code examination and pointing us towards
probable cause of the issue,
because we are unable to find it ourselves.
Thanks in advance and regards,
Dawid Macek
