Add a delay between killing teamd processes #3325
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When killing 10 or more teamd processes, add a delay of 0.1 seconds after every 10 kill signals/proceses. This is because in the LAG scale tests (in `ecmp/inner_hashing/test_inner_hashing_lag.py` in sonic-mgmt), it may create 100 LAGs, and when destroying them all, some of those LAGs may fail to be properly destroyed, leaving some stale port channels around. This seems to be because the netlink socket buffers on which the teamd processes get notifications become full with events of the other port channels/interfaces going down. As a workaround, add some delays in killing the teamd processes, so that the netlink buffers don't become full, causing messages to get dropped. This delay was randomly chosen, and it seems to work well with 100 LAGs on a KVM. It can probably made to be a bit more aggressive if needed (i.e. maybe 0.05 seconds every 20 processes). Signed-off-by: Saikrishna Arcot <sarcot@microsoft.com>
Signed-off-by: Saikrishna Arcot <sarcot@microsoft.com>
This requires overriding some libc functions and capturing information about kill signals sent or intercepting file open operations. Signe -off-by: Saikrishna Arcot <sarcot@microsoft.com>
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/azpw run |
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/AzurePipelines run |
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Azure Pipelines successfully started running 1 pipeline(s). |
Signed-off-by: Saikrishna Arcot <sarcot@microsoft.com>
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Comparing the time needed to send SIGTERM to the teamd processes before and after this change, it appears that the time is roughly the same for about 70 LAGs, as tested on a physical device. Before: After: In both cases, for 70 LAGs, it took about 0.6-0.7 seconds to send SIGTERM to the teamd processes, but the distribution of SIGTERMs sent is different. However, on this device, there are still some netlink messages getting dropped resulting in the cleanup not being complete. |
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@saiarcot895 Can you please run your changes with test_po_cleanup and test_po_cleanup_after_reload? We are noticing these tests statically fail with your changes |
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What I did
When killing 10 or more teamd processes, add a delay of 0.1 seconds after every 10 kill signals/proceses. This is because in the LAG scale tests (in
ecmp/inner_hashing/test_inner_hashing_lag.pyin sonic-mgmt), it may create 100 LAGs, and when destroying them all, some of those LAGs may fail to be properly destroyed, leaving some stale port channels around. This seems to be because the netlink socket buffers on which the teamd processes get notifications become full with events of the other port channels/interfaces going downWhy I did it
As a workaround, add some delays in killing the teamd processes, so that the netlink buffers don't become full, causing messages to get dropped.
This delay was randomly chosen, and it seems to work well with 100 LAGs on a KVM. It can probably made to be a bit more aggressive if needed (i.e. maybe 0.05 seconds every 20 processes).
How I verified it
On a KVM testbed with t0-116 topology with a bit more than 100 LAGs, stop teamd using
sudo systemctl stop teamd, and verify that all of the LAGs were deleted, and there were no messages from the kernel similar to the following:Details if related
Partial fix for sonic-net/sonic-buildimage#19310.