[dpdk-dev] Performances are not scale with multiple ports

[Shinae Woo]

Thanks for sharing Naoto.

So in your experiments, the forwarding performance still does not reach the
line rate.

Your perf record shows that the cpu spend most of the time in polling for
receiving packets,
and no other heavy operation.
Even though the application polling packets in its best,
the forwarder miss some packets from elsewhere from the application-side.

The dpdk document shows that 160Mpps forwarding performance in 2 sockets,
but I can only reach the 13 Mpps in 2 ports.
Even doubling the number of ports to 4 ports, the performance is still less
than 17Mpps.

I want to know where is the bottleneck lies in my environments, or
how I can reprocuce the same performance as the dpdk published.

Thank you,
Shinae



On Tue, May 28, 2013 at 11:30 AM, Naoto MATSUMOTO
<n-matsumoto at sakura.ad.jp>wrote:

>
> FYI: Disruptive IP Networking with Intel DPDK on Linux
> http://slidesha.re/SeVFZo
>
>
> On Tue, 28 May 2013 11:26:30 +0900
> Shinae Woo <shinae2012 at gmail.com> wrote:
>
> > Hello, all.
> >
> > I play the dpdk-1.2.3r1 with examples.
> >
> > But I can not achieve the line-rate packet receive performance,
> > and the performance is not scale with multiple ports.
> >
> > For example, in example l2fwd, I have tested two cases with 2 ports, and
> 4
> > ports,
> > using belowed command line each
> >
> > ./build/l2fwd -cf -n3 -- -p3
> > ./build/l2fwd -cf -n3 -- -pf
> >
> > But both cases, the aggregated performance are not scale.
> >
> > == experiments environments ==
> > - Two Intel 82599 NICs (total 4 ports)
> > - Intel Xeon X5690  @ 3.47GHz * 2 (total 12 cores)
> > - 1024 * 2MB hugepages
> > - Linux 2.6.38-15-server
> > - Each ports receiving 10Gbps of traffic of 64 bytes packets, 14.88Mpps.
> >
> > *1. Packet forwarding performance*
> >
> > In 2 ports case,  receive performance is 13Mpps,
> > In 4 ports case,  not 26Mbps, only 16.8Mpps.
> >
> > Port statistics ====================================
> > Statistics for port 0 ------------------------------
> > Packets sent:                  4292256
> > Packets received:              6517396
> > Packets dropped:               2224776
> > Statistics for port 1 ------------------------------
> > Packets sent:                  4291840
> > Packets received:              6517044
> > Packets dropped:               2225556
> > Aggregate statistics ===============================
> > Total packets sent:            8584128
> > Total packets received:       13034472
> > Total packets dropped:         4450332
> > ====================================================
> >
> > Port statistics ====================================
> > Statistics for port 0 ------------------------------
> > Packets sent:                  1784064
> > Packets received:              2632700
> > Packets dropped:                848128
> > Statistics for port 1 ------------------------------
> > Packets sent:                  1784104
> > Packets received:              2632196
> > Packets dropped:                848596
> > Statistics for port 2 ------------------------------
> > Packets sent:                  3587616
> > Packets received:              5816344
> > Packets dropped:               2200176
> > Statistics for port 3 ------------------------------
> > Packets sent:                  3587712
> > Packets received:              5787848
> > Packets dropped:               2228684
> > Aggregate statistics ===============================
> > Total packets sent:           10743560
> > Total packets received:       16869152
> > Total packets dropped:         6125608
> > ====================================================
> >
> > *2. Packet receiving performance*
> > I fix the codes for only receiving packets (not forwarding),
> > the performance is still not scalable as each 13.3Mpps, 18Mpps.
> >
> > Port statistics ====================================
> > Statistics for port 0 ------------------------------
> > Packets sent:                        0
> > Packets received:              6678860
> > Packets dropped:                     0
> > Statistics for port 1 ------------------------------
> > Packets sent:                        0
> > Packets received:              6646120
> > Packets dropped:                     0
> > Aggregate statistics ===============================
> > Total packets sent:                  0
> > Total packets received:       13325012
> > Total packets dropped:               0
> > ====================================================
> >
> > Port statistics ====================================
> > Statistics for port 0 ------------------------------
> > Packets sent:                        0
> > Packets received:              3129624
> > Packets dropped:                     0
> > Statistics for port 1 ------------------------------
> > Packets sent:                        0
> > Packets received:              3131292
> > Packets dropped:                     0
> > Statistics for port 2 ------------------------------
> > Packets sent:                        0
> > Packets received:              6260908
> > Packets dropped:                     0
> > Statistics for port 3 ------------------------------
> > Packets sent:                        0
> > Packets received:              6238764
> > Packets dropped:                     0
> > Aggregate statistics ===============================
> > Total packets sent:                  0
> > Total packets received:       18760640
> > Total packets dropped:               0
> > ====================================================
> >
> > The question is that
> > 1. How I can achieve each port receiving full 14.88Mpps ?
> >     What might be the bottleneck in current environment?
> > 2. Why the performance using multiple ports is not scale?
> >     I guess doubling ports shows the doubling the receiving performance,
> >     but it shows not. I am curious about what is limiting the packet
> > receivng performance.
> >
> > Thanks,
> > Shinae
>
> --
> SAKURA Internet Inc. / Senior Researcher
> Naoto MATSUMOTO <n-matsumoto at sakura.ad.jp>
> SAKURA Internet Research Center <http://research.sakura.ad.jp/>
>
>
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