Hi.
This is common trouble due to hierarchical shapers realization (global
tree lock on packet dequeuing - so when one CPU looks for parent class
where tokens can be borrowed, other CPUs are waiting). It's mentioned
even in academic publications :) You can read about it here:
http://www.ijcset.com/docs/IJCSET13-04-04-113.pdf
I think that simple lock removing will greatly improve performance; and
race conditions on packets dequeuing shouldn't hurt anything except
shaping accuracy. Another solutions looks more complex.
03.11.2015 21:49, Eric Dumazet пишет:
On Tue, 2015-11-03 at 21:17 +0200, Denys Fedoryshchenko wrote:
GSO/TSO on the output and watch performance coming back.
It is not, since i have more than 120 servers installed over country
(most of them handle small traffic), in forwarding mode, first thing i
am doing on forwarding setup - disabling gro/gso/tso. It is helped also
many ISP on their forum where i visit often, first thing in
troubleshooting unreliable network traffic forwarding - disabling
offloading.
Because problem starts from incorrect shaping, and ends in some cases
with network drivers spitting watchdog errors. Sometimes even shaper not
necessary, just plain forwarding with offload enabled can cause issues,
but it might be bug in networking drivers.
Should i try to reproduce and report? Sure if anybody can look into this
issue.
Well, I am telling you.
Say no to people advising to turn off GRO/TSO.
If you were the guy adviding others to do so, it is time to see the
light.
Lets fix the bugs if any, instead of spreading disinformation.
I am so tired of telling these very simple facts guys.
If you prefer, continue to work on linux-2.0 but don't ask help on
netdev.
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