Re: [dpdk-dev] Best example for showing throughput?

[Patrick Mahan <mahan@mahan.org>]

On May 25, 2013, at 1:59 PM, Damien Millescamps <damien.millescamps@6wind.com> wrote:

> On 05/25/2013 09:23 PM, Damien Millescamps wrote:
>> Hi Patrick,
>> 
>> If you are using both ports of the same Niantics at the same time then
>> you won't be able to reach the line-rate on both port.
> 
> For a better explanation, you can refer to this post from Alexander
> Duyck from Intel on the linux network mailing list:
> 
> http://permalink.gmane.org/gmane.linux.network/207295
> 

Interesting article.

Okay, I attempted to find the bus rate of this card this morning (the output of lspci is below).

This shows me I am capable of 5GT/s raw which works out to 4 Gbps/lane with 8 lanes enabled which should, theoretically, give 32 Gbps.  Reading the article, the suggestion is that due to the smaller packet the overhead is contributing to more 50% of the PCIe bus traffic.  Given that I'm seeing a forwarding speed of only about 12.282 Mpps with ~17% drops for only in one direction (rss enabled, 7 queues enabled with 6 queues used).

So the overhead cost is almost 70%?

Can this ever do line rate?  Under what conditions? It has been my experience that the industry standard is testing throughput using these 64 byte packets.

Output of 'lspci -vvv -s 03:00.0':

03:00.0 Ethernet controller: Intel Corporation 82599EB 10-Gigabit SFI/SFP+ Network Connection (rev
 01)
        Subsystem: Intel Corporation Ethernet Server Adapter X520-2
        Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2
B- DisINTx+
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <P
ERR- INTx-
        Latency: 0, Cache Line Size: 64 bytes
        Interrupt: pin A routed to IRQ 48
        Region 0: Memory at d9080000 (64-bit, prefetchable) [size=512K]
        Region 2: I/O ports at ecc0 [size=32]
        Region 4: Memory at d91f8000 (64-bit, prefetchable) [size=16K]
        Capabilities: [40] Power Management version 3
                Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0+,D1-,D2-,D3hot+,D3cold-)
                Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=1 PME-
        Capabilities: [50] MSI: Enable- Count=1/1 Maskable+ 64bit+
                Address: 0000000000000000  Data: 0000
                Masking: 00000000  Pending: 00000000
        Capabilities: [70] MSI-X: Enable+ Count=64 Masked-
                Vector table: BAR=4 offset=00000000
                PBA: BAR=4 offset=00002000
        Capabilities: [a0] Express (v2) Endpoint, MSI 00
                DevCap: MaxPayload 512 bytes, PhantFunc 0, Latency L0s <512ns, L1 <64us
                        ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset+
                DevCtl: Report errors: Correctable- Non-Fatal+ Fatal+ Unsupported+
                        RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+ FLReset-
                        MaxPayload 256 bytes, MaxReadReq 512 bytes
                DevSta: CorrErr+ UncorrErr- FatalErr- UnsuppReq+ AuxPwr- TransPend-
                LnkCap: Port #0, Speed 5GT/s, Width x8, ASPM L0s, Latency L0 <1us, L1 <8us
                        ClockPM- Surprise- LLActRep- BwNot-
                LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- Retrain- CommClk+
                        ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
                LnkSta: Speed 5GT/s, Width x8, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
                DevCap2: Completion Timeout: Range ABCD, TimeoutDis+, LTR-, OBFF Not Supported
                DevCtl2: Completion Timeout: 65ms to 210ms, TimeoutDis-, LTR-, OBFF Disabled
                LnkCtl2: Target Link Speed: 5GT/s, EnterCompliance- SpeedDis-
                         Transmit Margin: Normal Operating Range, EnterModifiedCompliance- Complia
nceSOS-
                         Compliance De-emphasis: -6dB
                LnkSta2: Current De-emphasis Level: -6dB, EqualizationComplete-, EqualizationPhase
1-
                         EqualizationPhase2-, EqualizationPhase3-, LinkEqualizationRequest-
        Capabilities: [100 v1] Advanced Error Reporting
                UESta:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- Un
supReq- ACSViol-
                UEMsk:  DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt+ UnxCmplt+ RxOF- MalfTLP- ECRC- Un
supReq- ACSViol-
                UESvrt: DLP+ SDES- TLP+ FCP+ CmpltTO+ CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC+ Un
supReq- ACSViol-
                CESta:  RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr+
                CEMsk:  RxErr+ BadTLP+ BadDLLP+ Rollover+ Timeout+ NonFatalErr+
                AERCap: First Error Pointer: 00, GenCap+ CGenEn- ChkCap+ ChkEn-
        Capabilities: [140 v1] Device Serial Number 00-1b-21-ff-ff-6b-8d-d4
        Capabilities: [150 v1] Alternative Routing-ID Interpretation (ARI)
                ARICap: MFVC- ACS-, Next Function: 1
                ARICtl: MFVC- ACS-, Function Group: 0
        Capabilities: [160 v1] Single Root I/O Virtualization (SR-IOV)
                IOVCap: Migration-, Interrupt Message Number: 000
                IOVCtl: Enable- Migration- Interrupt- MSE- ARIHierarchy+
                IOVSta: Migration-
                Initial VFs: 64, Total VFs: 64, Number of VFs: 64, Function Dependency Link: 00
                VF offset: 128, stride: 2, Device ID: 10ed
                Supported Page Size: 00000553, System Page Size: 00000001
                Region 0: Memory at 00000000d0000000 (64-bit, non-prefetchable)
                Region 3: Memory at 00000000d0100000 (64-bit, non-prefetchable)
                VF Migration: offset: 00000000, BIR: 0
        Kernel driver in use: igb_uio
        Kernel modules: ixgbe

Thanks,

Patrick 

> Regards,
> -- 
> Damien Millescamps