On Wed, 2021-06-23 at 22:37 +0200, Olivier Cochard-Labbé wrote:
> 
> FreeBSD includes now multiple route lookup algorithms [1]:
> - bsearch: Binary search used if less than 16 routes installed;
> - radix_lockless: selected if you have more than 16 but less than 1000
> routes installed;
> - radix: radix (compressed binary tree), the default one used as
> fallback
> - dpdk_lpm: DPDK RTE Longuest Prefix Match (need to load kernel
> modules: dpdk_lpm4.ko and dpdk_lpm6.ko, which is done on BSDRP)
> - dxr: very fast IPv4 LPM (need to load kernel module: fib_dxr.ko)
> 
> Currently you are using the dpdk algo, but could you revert back to the
> historical default (radix) to check if it solves your problem ?
> You could try a :
> sysctl net.route.algo.inet.algo=radix4

Thank you, that did the trick:

[root@amarklor]/etc# traceroute -n 51.15.183.144
traceroute to 51.15.183.144 (51.15.183.144), 64 hops max, 40 byte
packets
 1  149.6.174.241  0.882 ms  0.502 ms  0.508 ms
 2  154.25.12.205  1.242 ms

149.6.174.241 as a first hop reflects the kernel routing-table.

CPU-Usage increased by about the factor of 3, but no Core runs over
10% usage, such quite some headroom here.

Seems that the dpdk forwarder needs some work. But you also
mentioned dxr. I remember that from over a decade ago, It 
was pretty impressive performance-wise. Any caveats here?

More spefically: why does BSDRP prefer dpdk over dxr? The
latter has adjustable Lookup-Table mask-lenghts, and the 
/24 in dpdk seem a little bit over-the-top (yes, there are
tons ov /24, but these /24 are usually from Network operators 
without clue (if not from the old historic swamp-space).


Networks with sufficiently high bandwidth / pps demands are rarely 
more precise than a /20; so to be on the safe side going with a 
/21 or /22 Table-Index should yield good results.

cu
    Clemens.

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