Tuning Rangeley Atom C2758 for gigabit speeds - A1SRi-2758F board



  • I just signed up for centurylink gigabit fiber and using their router I'm able to get 930+up/down speeds.

    I'm using a A1SRi-2758F board with 8gb RAM.
    This is a Rangeley Atom C2758 system (8-core)

    I'm only getting about 750mbit/s down but I am able to get 930+mbit/s up.

    I can't seem to get any faster than 750mbit/s.

    The running services are
    apcupsd (only thing installed from packages)
    apinger
    dhcpd
    ntpd
    radvd
    sshd
    unbound

    I've tried a few tweaks:
    net.inet.ip.fastforwarding=1
    net.inet.ip.redirect=0

    With no affect.

    I'm currently configured for 524288 mbufs and I've never seen that number get to 50k even.
    Any other ideas?  I have 3 port forwarding rules and the firewall itself has only about a dozen rules (a handful of them for the port fowards).

    Honestly, 750mbit/s is plenty fast enough, but this is one of those curiosity things that's getting to me.  Is the C2758 just not capable of handling this?

    I've tried running simulatneous speedtests thinking that it's a threading issue but it seems to just total to about the same 700-750 range.



  • https://forum.pfsense.org/index.php?topic=92718.0

    Found that thread.  Summary FreeBSD+PPPoE is apparently is incapable of using multiple receive queues.



  • @dopey:

    https://forum.pfsense.org/index.php?topic=92718.0

    Found that thread.  Summary FreeBSD+PPPoE is apparently is incapable of using multiple receive queues.

    I explained the issue in a post yesterday - it's the paragraph about the single queue issue. If the igb patch linked from the FreeBSD wiki works as described, it should sort this out, but you would have to rebuild pfSense yourself to incorporate it.

    This issue is being tracked as Redmine #4821. If there is no FreeBSD PR open for it, there really should be IMHO as it really should be sorted out in the base operating system. Incorporating the patch in pfSense would allow those who needed high throughput PPPoE on an igb interface (which is used by most if not all of the boxes that Netgate sells) to toggle the sysctl to bring the revised queueing behaviour into operation using the pfSense GUI.

    If Centurylink supports MTU 1500 operation using RFC 4638, you should find the RFC 4638 parts of my post yesterday to be in interesting.



  • Thanks.  That was really good info.  I had been trying to figure out if centurylink supports higher MTUs thinking I could try that to tweak out a bit more throughput.  Good to know that probably wouldn't have worked quite right with pfsense.

    I can't find much detail on trying anything more tan 1492 (which is what the centurylink provided gateway uses) and haven't wanted to reconfigure to see if it would work since it would require downing the PPPoE interface - i've found that changing ip addresses with ipv6 can be a pain in the butt and centurylink seems to give me a new ip address each time the interface is brought brought own and back up.

    I suppose one way around the queue issue would be to buy a /29 and route through the centurylink gateway instead of using pppoe :)



  • I'm only getting about 750mbit/s down but I am able to get 930+mbit/s up.

    The 930+ is ok, pending on the ~5% (50 MBit/s) less for doing SPI & NAT and the on top the
    overhead from 20 MBit/s this might be really fair.

    I can't seem to get any faster than 750mbit/s.

    If the pppoe is really and only running on only one CPU core it might be perhaps then also really
    impressive what this small Atom based 8 Core CPU is delivering here in this test.

    Honestly, 750mbit/s is plenty fast enough, but this is one of those curiosity things that's getting to me.  Is the C2758 just not capable of handling this?

    For sure there is then mostly also coming on top the application overhead and this might be different
    from each OS to others for sure. You can also try out a IPFire, OpenWRT, SmoothWall or ZeroShell
    and do this test once more again, then you will be sure this is not related to the used hardware, this
    C2758 board is really fast and powerful.because this operating systems are not coming with the one
    core problem on pppoe beside!

    I've tried running simulatneous speedtests thinking that it's a threading issue but it seems to
    just total to about the same 700-750 range.

    Would be nice to hear from you what you got with another installed system that is not
    coming with an multicore usage problem. But on the other hand an Atom Core is an Atom Core
    and if peoples will be able to route 1 GBit/s on WAN with SPI & NAT also, only using other CPUs
    it would be more tend then on the "small" Atom CPU Core, as I see it right, but with more electric
    power consuming.

    Intel Celeron J1900 @2,4GHz
    Intel Celeron G3260 @3,2GHz
    Intel Core i3 and Core i5 CPUs (not the smallest ones please)
    Intel Xeon E3-12xx v3/v4 Dual or Quad Core CPU
    Intel Xeon E5-2600 v3 CPUs

    So if this problem would be solved out you will be happy with this C2758 as I see it right
    because they are working on it, because they are selling the boards that are based on the same SoC.



  • @BlueKobold:

    If the pppoe is really and only running on only one CPU core it might be perhaps then also really
    impressive what this small Atom based 8 Core CPU is delivering here in this test.

    Agreed.  It's both disappointing that with PPPoE I cant get 1gb, but it is impressive to see that one of it's cores is pretty capable.

    For sure there is then mostly also coming on top the application overhead and this might be different
    from each OS to others for sure. You can also try out a IPFire, OpenWRT, SmoothWall or ZeroShell
    and do this test once more again, then you will be sure this is not related to the used hardware, this
    C2758 board is really fast and powerful.because this operating systems are not coming with the one
    core problem on pppoe beside!

    Yeah.  I'm pretty content with pfsense and my 700-750mbit/s :)
    I've been doing alot of playing around, and the fastest i've gotten from the other end has generally been 200-250mbit/s :)  So my connection is rarely a bottleneck.  hehe.

    I would like to play with different things, but I don't have extra hardware sitting around, or time to install different OSes on my router to test out.  Since this is the primarily router running the network for my entire house (and just about everything my wife and kids do is internet related) someone would kill me if our network was on and off alot.

    Would be nice to hear from you what you got with another installed system that is not
    coming with an multicore usage problem. But on the other hand an Atom Core is an Atom Core
    and if peoples will be able to route 1 GBit/s on WAN with SPI & NAT also, only using other CPUs
    it would be more tend then on the "small" Atom CPU Core, as I see it right, but with more electric
    power consuming.

    Intel Celeron J1900 @2,4GHz
    Intel Celeron G3260 @3,2GHz
    Intel Core i3 and Core i5 CPUs (not the smallest ones please)
    Intel Xeon E3-12xx v3/v4 Dual or Quad Core CPU
    Intel Xeon E5-2600 v3 CPUs

    So if this problem would be solved out you will be happy with this C2758 as I see it right
    because they are working on it, because they are selling the boards that are based on the same SoC.

    I'm not sure if you remember, but i commented on something similar on the build thread for this particular router build.  I was getting 930+mb/s up and down between a host on the WAN interface and a host on the LAN interface.  So when PPPoE is NOT in play, and it's simply routing traffic, absolutely this build will route gigabit NAT speeds.

    I'm actually thinking of buyinga /29 just so I can switch PPPoE to the centurylink provided router and reconfigure pfsense to just do routing through one of the external /29 ip addresses.  But realy, it's silly to pay $20/month US, just to be able to get a speedtest score showing 930Mbits vs 700-750 :)
    I had a /29 with my comcast business line, but only reason why I needed that was I didn't want to deal with the hassle of a DMZ and also dynamic DNS.

    pfsense makes both a firewalled off DMZ interface and dynnamic DNS updates super easy.


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