Hello! I executed deep test of Paul's toolkit and could approve performance degradation in 2.0.0.
On Sun, Apr 26, 2015 at 9:50 PM, Paul Emmerich <emmericp at net.in.tum.de> wrote: > Hi, > > I'm working on a DPDK-based packet generator [1] and I recently tried to > upgrade from DPDK 1.7.1 to 2.0.0. > However, I noticed that DPDK 1.7.1 is about 25% faster than 2.0.0 for my use > case. > > So I ran some basic performance tests on the l2fwd example with DPDK 1.7.1, > 1.8.0 and 2.0.0. > I used an Intel Xeon E5-2620 v3 CPU clocked down to 1.2 GHz in order to > ensure that the CPU and not the network bandwidth is the bottleneck. > I configured l2fwd to forward between two interfaces of an X540 NIC using > only a single CPU core (-q2) and measured the following throughput under > full bidirectional load: > > > Version TP [Mpps] Cycles/Pkt > 1.7.1 18.84 84.925690021 > 1.8.0 16.78 95.351609058 > 2.0.0 16.40 97.56097561 > > DPDK 1.7.1 is about 15% faster in this scenario. The obvious suspect is the > new mbuf structure introduced in DPDK 1.8, so I profiled L1 cache misses: > > Version L1 miss ratio > 1.7.1 6.5% > 1.8.0 13.8% > 2.0.0 13.4% > > > FWIW the performance results with my packet generator on the same 1.2 GHz > CPU core are: > > Version TP [Mpps] L1 cache miss ratio > 1.7 11.77 4.3% > 2.0 9.5 8.4% > > > The discussion about the original patch [2] which introduced the new mbuf > structure addresses this potential performance degradation and mentions that > it is somehow mitigated. > It even claims a 20% *increase* in performance in a specific scenario. > However, that doesn't seem to be the case for both l2fwd and my packet > generator. > > Any ideas how to fix this? A 25% loss in throughput prevents me from > upgrading to DPDK 2.0.0. I need the new lcore features and the 40 GBit > driver updates, so I can't stay on 1.7.1 forever. > > Paul > > > [1] https://github.com/emmericp/MoonGen > [2] http://comments.gmane.org/gmane.comp.networking.dpdk.devel/5155 -- Sincerely yours, Pavel Odintsov
