Hi Konstantin, Ruifeng, > -----Original Message----- > From: Ananyev, Konstantin <konstantin.anan...@intel.com> > Sent: Monday, April 8, 2019 3:00 PM > To: Ruifeng Wang (Arm Technology China) <ruifeng.w...@arm.com>; > Shreyansh Jain <shreyansh.j...@nxp.com>; dev@dpdk.org > Cc: nd <n...@arm.com> > Subject: RE: [dpdk-dev] [PATCH] examples/l3fwd: support separate buffer > pool per port > > > > > > > Hi Shreyansh, > > > > I tried this patch on MacchiatoBin + 82599 NIC. > > Compared with global-pool mode, per-port-pool mode showed slightly > lower performance in single core test. > > That was my thought too - for the case when queues from multiple ports > are handled by the same core > it probably would only slowdown things.
Thanks for your comments. This is applicable for cases where separate cores can handle separate ports - each with their pools. (somehow I felt that message in commit was adequate - I can rephrase if that is misleading) In case there is enough number of cores available for datapath, such segregation can result in better performance - possibly because of drop in pool and cache conflicts. At least on some of NXP SoC, this resulted in over 15% improvement. And, in other cases it didn't lead to any drop/negative-impact. > Wonder what is the use case for the patch and what is the performance > gain you observed? For hardware backed pools, hardware access and exclusion are expensive. By segregating pool/port/lcores it is possible to attain a conflict free path. This is the use-case this patch targets. And anyways, this is an optional feature. > Konstantin > > > In dual core test, both modes had nearly same performance. OK > > > > My setup only has two ports which is limited. > > Just want to know the per-port-pool mode has more performance gain > when many ports are bound to different cores? Yes, though not necessarily *many* - in my case, I had 4 ports and even then about ~10% improvement was directly visible. I increased the port count and I was able to touch about ~15%. I did pin each port to a separate core, though. But again, important point is that without this feature enabled, I didn't see any drop in performance. Did you observe any drop? > > > > Used commands: > > sudo ./examples/l3fwd/build/l3fwd -c 0x4 -w 0000:01:00.0 -w > 0000:01:00.1 -- -P -p 3 --config='(0,0,2),(1,0,2)' --per-port-pool > > sudo ./examples/l3fwd/build/l3fwd -c 0xc -w 0000:01:00.0 -w > 0000:01:00.1 -- -P -p 3 --config='(0,0,2),(1,0,3)' --per-port-pool > > > > Regards, > > /Ruifeng > > [...]
