On Thu, Apr 06, 2017 at 04:36:29AM +0530, Deepak Khandelwal wrote: > Hi, > > I am testing SCTP performance on 4.4.x mips kernel (Octeon 2 hardware) > I have a specific requirement of testing 130K packets per second with > each packet size of 278 bytes. Server(s) and Client(s) are running on > separate machines each with 16 CPU Core. > > I am running two instances of iperf3 Server and client in those > dedicated machines respectively. > Is there any dependency between two instances from SCTP PoV ? > > Case -1: when Running with one instance of Server and Client > > ./iperf3 --sctp -4 -c 18.18.18.1 -B 18.18.18.2 -p 45000 -V -l 278 -t 60 -A 10 > > > I am getting consistent bandwidth. > CPU usage of Client is 100 % That's good. > > > Case -2: when Running with two instances of Server and Client > > ./iperf3 --sctp -4 -c 18.18.18.1 -B 18.18.18.2 -p 45000 -V -l 278 -t 60 -A 10 > > ./iperf3 --sctp -4 -c 18.18.18.1 -B 18.18.18.2 -p 45020 -V -l 278 -t 60 -A 11 > > > the bandwidth is not consistent and sometimes even 0 . > CPU of both these process together reaches to 100% not individually. > so if one client CPU usage is 80% other one CPU usage is 20% > > I have pinned the servers and clients to dedicated CPU cores. and > softirq interrupts also are masked to these cores.(smp_affinity) > > I tried changing scheduling priority of these process to SCHED_RR > (earlier SCHED_OTHER) > but the situation is still the same. They are fighting over the same CPU on softirq handling and leading to packet drops (/proc/net/sctp/snmp will confirm the drops and T3 retransmits). Did you try enabling RFS and XPS? I don't know which NIC you're using but one that supports hashing SCTP is rare and this could help distribute the load better. If not, that's a good next step, specially RFS (or at least RSS). Marcelo -- To unsubscribe from this list: send the line "unsubscribe linux-sctp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
