Re: CFT: if_bridge performance improvements

From: Xin Li <delphij_at_delphij.net>
Date: Wed, 22 Apr 2020 09:15:31 -0700
On 4/22/20 01:45, Kristof Provost wrote:
> On 22 Apr 2020, at 10:20, Xin Li wrote:
>> Hi,
>>
>> On 4/14/20 02:51, Kristof Provost wrote:
>>> Hi,
>>>
>>> Thanks to support from The FreeBSD Foundation I’ve been able to work on
>>> improving the throughput of if_bridge.
>>> It changes the (data path) locking to use the NET_EPOCH infrastructure.
>>> Benchmarking shows substantial improvements (x5 in test setups).
>>>
>>> This work is ready for wider testing now.
>>>
>>> It’s under review here: https://reviews.freebsd.org/D24250
>>>
>>> Patch for CURRENT: https://reviews.freebsd.org/D24250?download=true
>>> Patches for stable/12:
>>> https://people.freebsd.org/~kp/if_bridge/stable_12/
>>>
>>> I’m not currently aware of any panics or issues resulting from these
>>> patches.
>>
>> I have observed the following panic with latest stable/12 after applying
>> the stable_12 patchset, it appears like a race condition related NULL
>> pointer deference, but I haven't took a deeper look yet.
>>
>> The box have 7 igb(4) NICs, with several bridge and VLAN configured
>> acting as a router.  Please let me know if you need additional
>> information; I can try -CURRENT as well, but it would take some time as
>> the box is relatively slow (it's a ZFS based system so I can create a
>> separate boot environment for -CURRENT if needed, but that would take
>> some time as I might have to upgrade the packages, should there be any
>> ABI breakages).
>>
> Thanks for the report. I don’t immediately see how this could happen.
> 
> Are you running an L2 firewall on that bridge by any chance? An earlier
> version of the patch had issues with a stray unlock in that code path.

I don't think I have a L2 firewall (I assume means filtering based on
MAC address like what can be done with e.g. ipfw?  The bridges were
created on vlan interfaces though, do they count as L2 firewall?), the
system is using pf with a few NAT rules:

$ sudo pfctl -s rules
anchor "miniupnpd" all
pass in quick inet6 proto tcp from <myv6> to any flags S/SA keep state
block drop in quick inet6 proto tcp from ! <myv6> to <myv6> flags S/SA
block drop in quick proto tcp from any os "Linux" to any port = ssh
pass out on igb6 inet proto tcp from (igb6) to any port = domain flags
S/SA keep state queue dns
pass out on igb6 inet proto udp from (igb6) to any port = domain keep
state queue dns
pass in on igb6 proto tcp from any to (igb6) port = http flags S/SA
modulate state queue(web, ack)
pass in on igb6 proto tcp from any to (igb6) port = https flags S/SA
modulate state queue(web, ack)
pass out on igb6 inet proto tcp from (igb6) to any flags S/SA modulate
state queue bulk
block drop in quick on igb6 proto tcp from <sshguard> to any port = ssh
label "ssh bruteforce"
block drop in on igb6 from <badhosts> to any

Cheers,


Received on Wed Apr 22 2020 - 14:15:38 UTC

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