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terintamel
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Joined: Sun Sep 05, 2010 3:09 am

Best Interface Queue type for CCR routers?

Thu Nov 19, 2015 8:16 pm

What is the best Interface queue-type for CCR routers assuming you are not using simple queues or queue trees?

Based on what I read it is not clear on if 'hardware-only' or 'multi-queue' is best.
"only-hardware-queue leaves interface with only hw transmit descriptor ring buffer which acts as a queue in itself. Usually at least 100 packets can be queued for transmit in transmit descriptor ring buffer. Transmit descriptor ring buffer size and the amount of packets that can be queued in it varies for different types of ethernet MACs.

Having no software queue is especially beneficial on SMP systems because it removes the requirement to synchronize access to it from different cpus/cores which is expensive.


multi-queue-ethernet-default can be beneficial on SMP systems with ethernet interfaces that have support for multiple transmit queues and have a linux driver support for multiple transmit queues. By having one software queue for each hardware queue there might be less time spent for synchronizing access to them."
I know that CCR routers are multi core by nature so does that mean I will get better performance with multi-queue or does that only apply to x86 SMD systems? What about multi-core PPC systems like 850Gx2?
 
hedele
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Re: Best Interface Queue type for CCR routers?

Fri Nov 20, 2015 12:11 am

If you are intending to use fastpath forwarding on the CCRs, you are required to use only-hardware-queue, as any other kind of interface queue will disable fastpath.

multi-queue-ethernet-default should be worth trying on x86 systems with compatible NICs (in system - resource - irq you see several interrupts like "eth0-rxtx0, eth0-rxtx1, eth0-rxtx2, ..." which shows support for multiple queues.) as only-hardware-queue is not supported on most NICs you will find on a x86 system.
 
satish143
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Re: Best Interface Queue type for CCR routers?

Mon Apr 04, 2016 5:30 pm

If you are intending to use fastpath forwarding on the CCRs, you are required to use only-hardware-queue, as any other kind of interface queue will disable fastpath.

multi-queue-ethernet-default should be worth trying on x86 systems with compatible NICs (in system - resource - irq you see several interrupts like "eth0-rxtx0, eth0-rxtx1, eth0-rxtx2, ..." which shows support for multiple queues.) as only-hardware-queue is not supported on most NICs you will find on a x86 system.
I have same question which is prefered queue for CCRs Routers. We are planning to run as a Router and going to run BGP on it. Should i stick with only-hardware-queue? I have enabled fastpath and we are using iptables rules too.. No sure how to check performance of fastpath?
 
hedele
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Joined: Tue Feb 24, 2009 11:23 pm

Re: Best Interface Queue type for CCR routers?

Tue Apr 05, 2016 12:02 pm

I'd say generally you should be using only-hardware-queue on pretty much every Mikrotik device (excluding x86 and some special cases like CRS125 which seem to work better with other queues). Having -ANY- firewall rule configured will disable fastpath, so you will need to use fasttrack instead.

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