[dpdk-dev] DPDK testpmd forwarding performace degradation

[dpdk-dev] DPDK testpmd forwarding performace degradation

[吴亚东]

65 bytes frame may degrade performace a lot.Thats related to DMA and cache.
When NIC dma packets to memory, NIC has to do read modify write if DMA size is partial cache line.So for 65 bytes, the first 64 bytes are ok. The next 1 byte NIC has to read the whole cache line, change one byte and update the cache line.
So in DPDK, CRC is not stripped and ethernet header aligned to cache line which causes ip header not aligned on 4 bytes.

 		 	   		  

Re: [dpdk-dev] DPDK testpmd forwarding performace degradation

[Alexander Belyakov]

Hello,

On Tue, Jan 27, 2015 at 5:49 AM, 吴亚东 <wuyd@outlook.com> wrote:

> 65 bytes frame may degrade performace a lot.Thats related to DMA and cache.
> When NIC dma packets to memory, NIC has to do read modify write if DMA
> size is partial cache line.So for 65 bytes, the first 64 bytes are ok. The
> next 1 byte NIC has to read the whole cache line, change one byte and
> update the cache line.
> So in DPDK, CRC is not stripped and ethernet header aligned to cache line
> which causes ip header not aligned on 4 bytes.
>
>
Extra cache line update indeed makes sense because performance is halved
with extra byte.

It is a little bit confusing, but the issue is not with switching from 64
bytes frames to 65 bytes frames, but with switching from 80 bytes frame to
81 bytes frame. Note that the issue disappears at 96 bytes frame size.

Alexander

Re: [dpdk-dev] DPDK testpmd forwarding performace degradation

[Alexander Belyakov]

On Thu, Jan 29, 2015 at 3:43 PM, Alexander Belyakov <abelyako@gmail.com>
wrote:

>
>
> On Wed, Jan 28, 2015 at 3:24 PM, Alexander Belyakov <abelyako@gmail.com>
> wrote:
>
>>
>>
>> On Tue, Jan 27, 2015 at 7:21 PM, De Lara Guarch, Pablo <
>> pablo.de.lara.guarch@intel.com> wrote:
>>
>>>
>>>
>>> > On Tue, Jan 27, 2015 at 10:51 AM, Alexander Belyakov
>>>
>>> > <abelyako@gmail.com> wrote:
>>>
>>> >
>>>
>>> > Hi Pablo,
>>>
>>> >
>>>
>>> > On Mon, Jan 26, 2015 at 5:22 PM, De Lara Guarch, Pablo
>>>
>>> > <pablo.de.lara.guarch@intel.com> wrote:
>>>
>>> > Hi Alexander,
>>>
>>> >
>>>
>>> > > -----Original Message-----
>>>
>>> > > From: dev [mailto:dev-bounces@dpdk.org <dev-bounces@dpdk.org>] On
>>> Behalf Of Alexander
>>>
>>> > Belyakov
>>>
>>> > > Sent: Monday, January 26, 2015 10:18 AM
>>>
>>> > > To: dev@dpdk.org
>>>
>>> > > Subject: [dpdk-dev] DPDK testpmd forwarding performace degradation
>>>
>>> > >
>>>
>>> > > Hello,
>>>
>>> > >
>>>
>>> > > recently I have found a case of significant performance degradation
>>> for our
>>>
>>> > > application (built on top of DPDK, of course). Surprisingly, similar
>>> issue
>>>
>>> > > is easily reproduced with default testpmd.
>>>
>>> > >
>>>
>>> > > To show the case we need simple IPv4 UDP flood with variable UDP
>>>
>>> > payload
>>>
>>> > > size. Saying "packet length" below I mean: Eth header length (14
>>> bytes) +
>>>
>>> > > IPv4 header length (20 bytes) + UPD header length (8 bytes) + UDP
>>> payload
>>>
>>> > > length (variable) + CRC (4 bytes). Source IP addresses and ports are
>>>
>>> > selected
>>>
>>> > > randomly for each packet.
>>>
>>> > >
>>>
>>> > > I have used DPDK with revisions 1.6.0r2 and 1.7.1. Both show the same
>>>
>>> > issue.
>>>
>>> > >
>>>
>>> > > Follow "Quick start" guide (http://dpdk.org/doc/quick-start) to
>>> build and
>>>
>>> > > run testpmd. Enable testpmd forwarding ("start" command).
>>>
>>> > >
>>>
>>> > > Table below shows measured forwarding performance depending on
>>>
>>> > packet
>>>
>>> > > length:
>>>
>>> > >
>>>
>>> > > No. -- UDP payload length (bytes) -- Packet length (bytes) --
>>> Forwarding
>>>
>>> > > performance (Mpps) -- Expected theoretical performance (Mpps)
>>>
>>> > >
>>>
>>> > > 1. 0 -- 64 -- 14.8 -- 14.88
>>>
>>> > > 2. 34 -- 80 -- 12.4 -- 12.5
>>>
>>> > > 3. 35 -- 81 -- 6.2 -- 12.38 (!)
>>>
>>> > > 4. 40 -- 86 -- 6.6 -- 11.79
>>>
>>> > > 5. 49 -- 95 -- 7.6 -- 10.87
>>>
>>> > > 6. 50 -- 96 -- 10.7 -- 10.78 (!)
>>>
>>> > > 7. 60 -- 106 -- 9.4 -- 9.92
>>>
>>> > >
>>>
>>> > > At line number 3 we have added 1 byte of UDP payload (comparing to
>>>
>>> > > previous
>>>
>>> > > line) and got forwarding performance halved! 6.2 Mpps against 12.38
>>> Mpps
>>>
>>> > > of
>>>
>>> > > expected theoretical maximum for this packet size.
>>>
>>> > >
>>>
>>> > > That is the issue.
>>>
>>> > >
>>>
>>> > > Significant performance degradation exists up to 50 bytes of UDP
>>> payload
>>>
>>> > > (96 bytes packet length), where it jumps back to theoretical maximum.
>>>
>>> > >
>>>
>>> > > What is happening between 80 and 96 bytes packet length?
>>>
>>> > >
>>>
>>> > > This issue is stable and 100% reproducible. At this point I am not
>>> sure if
>>>
>>> > > it is DPDK or NIC issue. These tests have been performed on Intel(R)
>>> Eth
>>>
>>> > > Svr Bypass Adapter X520-LR2 (X520LR2BP).
>>>
>>> > >
>>>
>>> > > Is anyone aware of such strange behavior?
>>>
>>> > I cannot reproduce the issue using two ports on two different 82599EB
>>> NICs,
>>>
>>> > using 1.7.1 and 1.8.0.
>>>
>>> > I always get either same or better linerate as I increase the packet
>>> size.
>>>
>>> >
>>>
>>> > Thank you for trying to reproduce the issue.
>>>
>>> >
>>>
>>> > Actually, have you tried using 1.8.0?
>>>
>>> >
>>>
>>> > I feel 1.8.0 is little bit immature and might require some post-release
>>>
>>> > patching. Even tespmd from this release is not forwarding packets
>>> properly
>>>
>>> > on my setup. It is up and running without visible errors/warnings,
>>> TX/RX
>>>
>>> > counters are ticking but I can not see any packets at the output.
>>>
>>>
>>>
>>> This is strange. Without  changing anything, forwarding works perfectly
>>> for me
>>>
>>> (so, RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC is enabled).
>>>
>>>
>>>
>>> >Please note, both 1.6.0r2 and 1.7.1 releases work (on the same setup)
>>> out-of-the-box just
>>>
>>> > fine with only exception of this mysterious performance drop.
>>>
>>> > So it will take some time to figure out what is wrong with dpdk-1.8.0.
>>>
>>> > Meanwhile we could focus on stable dpdk-1.7.1.
>>>
>>> >
>>>
>>> > Managed to get testpmd from dpdk-1.8.0 to work on my setup.
>>>
>>> > Unfortunately I had to disable RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC,
>>>
>>> > it is new comparing to 1.7.1 and somehow breaks testpmd forwarding. By
>>> the
>>>
>>> > way, simply disabling RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC in
>>>
>>> > common_linuxapp config file breaks the build - had to make
>>> quick'n'dirty fix
>>>
>>> > in struct igb_rx_queue as well.
>>>
>>> >
>>>
>>> > Anyway, issue is still here.
>>>
>>> >
>>>
>>> > Forwarding 80 bytes packets at 12.4 Mpps.
>>>
>>> > Forwarding 81 bytes packets at 7.2 Mpps.
>>>
>>> >
>>>
>>> > Any ideas?
>>>
>>> > As for X520-LR2 NIC - it is dual port bypass adapter with device id
>>> 155d. I
>>>
>>> > believe it should be treated as 82599EB except bypass feature. I put
>>> bypass
>>>
>>> > mode to "normal" in those tests.
>>>
>>>
>>>
>>> I have used a 82599EB first, and now a X520-SR2. Same results.
>>>
>>> I assume that X520-SR2 and X520-LR2 should give similar results
>>>
>>> (only thing that is changed is the wavelength, but the controller is the
>>> same).
>>>
>>>
>>>
>> It seems I found what was wrong, at least got a hint.
>>
>> My build server machine type differs from test setup. Until now it was OK
>> to build DPDK with -march=native.
>>
>> I found that building dpdk-1.8.0 with explicitly set core-avx-i (snb,
>> ivb) or bdver2 (amd) machine types almost eliminates performance drop. The
>> same goes for RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC option issues.
>>
>> It seems DPDK performance and stability depends on machine type more than
>> I was expecting.
>>
>> Thank you for your help.
>>
>>
> Mysteries are still here.
>
> While single RX queue forwarding shows almost no degradation now, multiple
> RX queues still do.
>
> Launching
>
> ./testpmd -c7 -n3 -- -i --rxq=2 --txq=2 --nb-cores=2 --nb-ports=2
>
> shows the following result:
>
> 80 bytes packets are being forwarded at 12.46Mpps rate (which is fine)
> 81 bytes packets are being forwarded at 7.5Mpps rate (which is weird)
>
> Pablo, could you please check on your setup if multiple RX queues shows no
> performance degradation depending on packet size?
>
> Additional information about packets I'm sending.
> 80 bytes packet is IPv4 UDP packet (with random source IP/port) and 34
> payload bytes.
> 81 bytes packet is IPv4 UDP packet (with random source IP/port) and 35
> payload bytes.
>
> Thank you,
> Alexander
>
>
Just FYI.

I have run more tests on multiple hardware configurations. It seems issue
appears only with AMD based servers.

I have tried two HP ProLiant DL385p G8 servers. One with AMD Opteron(TM)
Processor 6272 and one with AMD Opteron(tm) Processor 6376). Also I have
used dual port Intel(R) Eth Svr Bypass Adapter X520-LR2 (X520LR2BP) and two
single port Intel(R) Eth Converged Network Adapter X520-LR1 (E10G41BFLRBLK)
adapters.

All configurations based on these hardware pieces show significant
forwarding performance degradation depending on packet size.

Please take a look at the following image link to understand what I am
talking about. This diagram is based on 1.6.0r2, but I have tried other
versions including 1.8.0 and issue remains.

https://drive.google.com/file/d/0B8wI4oKPHe0DaUNKdEdVdnUyRXc/view?usp=sharing

But this is not the end. As soon as I switched to HP ProLiant DL380p Gen8
with Intel(R) Xeon(R) CPU E5-2690 on board everything started to work
perfectly - forwarding performance matches theoretical expectations.

At the moment I have no idea what is wrong with AMD platforms (or what i am
doing wrong).

If someone needs more details on these experiments or knows how to fix
that, please let me know.

Regards,
Alexander


>
>
>> Alexander
>>
>>  Pablo
>>>
>>> > Alexander
>>>
>>> >
>>>
>>> >
>>>
>>> > Pablo
>>>
>>> > >
>>>
>>> > > Regards,
>>>
>>> > > Alexander Belyakov
>>>
>>> >
>>>
>>> >
>>>
>>>
>>>
>>>
>>>
>>
>>
>

Re: [dpdk-dev] DPDK testpmd forwarding performace degradation

[Alexander Belyakov]

On Wed, Jan 28, 2015 at 3:24 PM, Alexander Belyakov <abelyako@gmail.com>
wrote:

>
>
> On Tue, Jan 27, 2015 at 7:21 PM, De Lara Guarch, Pablo <
> pablo.de.lara.guarch@intel.com> wrote:
>
>>
>>
>> > On Tue, Jan 27, 2015 at 10:51 AM, Alexander Belyakov
>>
>> > <abelyako@gmail.com> wrote:
>>
>> >
>>
>> > Hi Pablo,
>>
>> >
>>
>> > On Mon, Jan 26, 2015 at 5:22 PM, De Lara Guarch, Pablo
>>
>> > <pablo.de.lara.guarch@intel.com> wrote:
>>
>> > Hi Alexander,
>>
>> >
>>
>> > > -----Original Message-----
>>
>> > > From: dev [mailto:dev-bounces@dpdk.org <dev-bounces@dpdk.org>] On
>> Behalf Of Alexander
>>
>> > Belyakov
>>
>> > > Sent: Monday, January 26, 2015 10:18 AM
>>
>> > > To: dev@dpdk.org
>>
>> > > Subject: [dpdk-dev] DPDK testpmd forwarding performace degradation
>>
>> > >
>>
>> > > Hello,
>>
>> > >
>>
>> > > recently I have found a case of significant performance degradation
>> for our
>>
>> > > application (built on top of DPDK, of course). Surprisingly, similar
>> issue
>>
>> > > is easily reproduced with default testpmd.
>>
>> > >
>>
>> > > To show the case we need simple IPv4 UDP flood with variable UDP
>>
>> > payload
>>
>> > > size. Saying "packet length" below I mean: Eth header length (14
>> bytes) +
>>
>> > > IPv4 header length (20 bytes) + UPD header length (8 bytes) + UDP
>> payload
>>
>> > > length (variable) + CRC (4 bytes). Source IP addresses and ports are
>>
>> > selected
>>
>> > > randomly for each packet.
>>
>> > >
>>
>> > > I have used DPDK with revisions 1.6.0r2 and 1.7.1. Both show the same
>>
>> > issue.
>>
>> > >
>>
>> > > Follow "Quick start" guide (http://dpdk.org/doc/quick-start) to
>> build and
>>
>> > > run testpmd. Enable testpmd forwarding ("start" command).
>>
>> > >
>>
>> > > Table below shows measured forwarding performance depending on
>>
>> > packet
>>
>> > > length:
>>
>> > >
>>
>> > > No. -- UDP payload length (bytes) -- Packet length (bytes) --
>> Forwarding
>>
>> > > performance (Mpps) -- Expected theoretical performance (Mpps)
>>
>> > >
>>
>> > > 1. 0 -- 64 -- 14.8 -- 14.88
>>
>> > > 2. 34 -- 80 -- 12.4 -- 12.5
>>
>> > > 3. 35 -- 81 -- 6.2 -- 12.38 (!)
>>
>> > > 4. 40 -- 86 -- 6.6 -- 11.79
>>
>> > > 5. 49 -- 95 -- 7.6 -- 10.87
>>
>> > > 6. 50 -- 96 -- 10.7 -- 10.78 (!)
>>
>> > > 7. 60 -- 106 -- 9.4 -- 9.92
>>
>> > >
>>
>> > > At line number 3 we have added 1 byte of UDP payload (comparing to
>>
>> > > previous
>>
>> > > line) and got forwarding performance halved! 6.2 Mpps against 12.38
>> Mpps
>>
>> > > of
>>
>> > > expected theoretical maximum for this packet size.
>>
>> > >
>>
>> > > That is the issue.
>>
>> > >
>>
>> > > Significant performance degradation exists up to 50 bytes of UDP
>> payload
>>
>> > > (96 bytes packet length), where it jumps back to theoretical maximum.
>>
>> > >
>>
>> > > What is happening between 80 and 96 bytes packet length?
>>
>> > >
>>
>> > > This issue is stable and 100% reproducible. At this point I am not
>> sure if
>>
>> > > it is DPDK or NIC issue. These tests have been performed on Intel(R)
>> Eth
>>
>> > > Svr Bypass Adapter X520-LR2 (X520LR2BP).
>>
>> > >
>>
>> > > Is anyone aware of such strange behavior?
>>
>> > I cannot reproduce the issue using two ports on two different 82599EB
>> NICs,
>>
>> > using 1.7.1 and 1.8.0.
>>
>> > I always get either same or better linerate as I increase the packet
>> size.
>>
>> >
>>
>> > Thank you for trying to reproduce the issue.
>>
>> >
>>
>> > Actually, have you tried using 1.8.0?
>>
>> >
>>
>> > I feel 1.8.0 is little bit immature and might require some post-release
>>
>> > patching. Even tespmd from this release is not forwarding packets
>> properly
>>
>> > on my setup. It is up and running without visible errors/warnings, TX/RX
>>
>> > counters are ticking but I can not see any packets at the output.
>>
>>
>>
>> This is strange. Without  changing anything, forwarding works perfectly
>> for me
>>
>> (so, RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC is enabled).
>>
>>
>>
>> >Please note, both 1.6.0r2 and 1.7.1 releases work (on the same setup)
>> out-of-the-box just
>>
>> > fine with only exception of this mysterious performance drop.
>>
>> > So it will take some time to figure out what is wrong with dpdk-1.8.0.
>>
>> > Meanwhile we could focus on stable dpdk-1.7.1.
>>
>> >
>>
>> > Managed to get testpmd from dpdk-1.8.0 to work on my setup.
>>
>> > Unfortunately I had to disable RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC,
>>
>> > it is new comparing to 1.7.1 and somehow breaks testpmd forwarding. By
>> the
>>
>> > way, simply disabling RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC in
>>
>> > common_linuxapp config file breaks the build - had to make
>> quick'n'dirty fix
>>
>> > in struct igb_rx_queue as well.
>>
>> >
>>
>> > Anyway, issue is still here.
>>
>> >
>>
>> > Forwarding 80 bytes packets at 12.4 Mpps.
>>
>> > Forwarding 81 bytes packets at 7.2 Mpps.
>>
>> >
>>
>> > Any ideas?
>>
>> > As for X520-LR2 NIC - it is dual port bypass adapter with device id
>> 155d. I
>>
>> > believe it should be treated as 82599EB except bypass feature. I put
>> bypass
>>
>> > mode to "normal" in those tests.
>>
>>
>>
>> I have used a 82599EB first, and now a X520-SR2. Same results.
>>
>> I assume that X520-SR2 and X520-LR2 should give similar results
>>
>> (only thing that is changed is the wavelength, but the controller is the
>> same).
>>
>>
>>
> It seems I found what was wrong, at least got a hint.
>
> My build server machine type differs from test setup. Until now it was OK
> to build DPDK with -march=native.
>
> I found that building dpdk-1.8.0 with explicitly set core-avx-i (snb, ivb)
> or bdver2 (amd) machine types almost eliminates performance drop. The same
> goes for RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC option issues.
>
> It seems DPDK performance and stability depends on machine type more than
> I was expecting.
>
> Thank you for your help.
>
>
Mysteries are still here.

While single RX queue forwarding shows almost no degradation now, multiple
RX queues still do.

Launching

./testpmd -c7 -n3 -- -i --rxq=2 --txq=2 --nb-cores=2 --nb-ports=2

shows the following result:

80 bytes packets are being forwarded at 12.46Mpps rate (which is fine)
81 bytes packets are being forwarded at 7.5Mpps rate (which is weird)

Pablo, could you please check on your setup if multiple RX queues shows no
performance degradation depending on packet size?

Additional information about packets I'm sending.
80 bytes packet is IPv4 UDP packet (with random source IP/port) and 34
payload bytes.
81 bytes packet is IPv4 UDP packet (with random source IP/port) and 35
payload bytes.

Thank you,
Alexander



> Alexander
>
>  Pablo
>>
>> > Alexander
>>
>> >
>>
>> >
>>
>> > Pablo
>>
>> > >
>>
>> > > Regards,
>>
>> > > Alexander Belyakov
>>
>> >
>>
>> >
>>
>>
>>
>>
>>
>
>

Re: [dpdk-dev] DPDK testpmd forwarding performace degradation

[Alexander Belyakov]

On Tue, Jan 27, 2015 at 7:21 PM, De Lara Guarch, Pablo <
pablo.de.lara.guarch@intel.com> wrote:

>
>
> > On Tue, Jan 27, 2015 at 10:51 AM, Alexander Belyakov
>
> > <abelyako@gmail.com> wrote:
>
> >
>
> > Hi Pablo,
>
> >
>
> > On Mon, Jan 26, 2015 at 5:22 PM, De Lara Guarch, Pablo
>
> > <pablo.de.lara.guarch@intel.com> wrote:
>
> > Hi Alexander,
>
> >
>
> > > -----Original Message-----
>
> > > From: dev [mailto:dev-bounces@dpdk.org <dev-bounces@dpdk.org>] On
> Behalf Of Alexander
>
> > Belyakov
>
> > > Sent: Monday, January 26, 2015 10:18 AM
>
> > > To: dev@dpdk.org
>
> > > Subject: [dpdk-dev] DPDK testpmd forwarding performace degradation
>
> > >
>
> > > Hello,
>
> > >
>
> > > recently I have found a case of significant performance degradation
> for our
>
> > > application (built on top of DPDK, of course). Surprisingly, similar
> issue
>
> > > is easily reproduced with default testpmd.
>
> > >
>
> > > To show the case we need simple IPv4 UDP flood with variable UDP
>
> > payload
>
> > > size. Saying "packet length" below I mean: Eth header length (14
> bytes) +
>
> > > IPv4 header length (20 bytes) + UPD header length (8 bytes) + UDP
> payload
>
> > > length (variable) + CRC (4 bytes). Source IP addresses and ports are
>
> > selected
>
> > > randomly for each packet.
>
> > >
>
> > > I have used DPDK with revisions 1.6.0r2 and 1.7.1. Both show the same
>
> > issue.
>
> > >
>
> > > Follow "Quick start" guide (http://dpdk.org/doc/quick-start) to build
> and
>
> > > run testpmd. Enable testpmd forwarding ("start" command).
>
> > >
>
> > > Table below shows measured forwarding performance depending on
>
> > packet
>
> > > length:
>
> > >
>
> > > No. -- UDP payload length (bytes) -- Packet length (bytes) --
> Forwarding
>
> > > performance (Mpps) -- Expected theoretical performance (Mpps)
>
> > >
>
> > > 1. 0 -- 64 -- 14.8 -- 14.88
>
> > > 2. 34 -- 80 -- 12.4 -- 12.5
>
> > > 3. 35 -- 81 -- 6.2 -- 12.38 (!)
>
> > > 4. 40 -- 86 -- 6.6 -- 11.79
>
> > > 5. 49 -- 95 -- 7.6 -- 10.87
>
> > > 6. 50 -- 96 -- 10.7 -- 10.78 (!)
>
> > > 7. 60 -- 106 -- 9.4 -- 9.92
>
> > >
>
> > > At line number 3 we have added 1 byte of UDP payload (comparing to
>
> > > previous
>
> > > line) and got forwarding performance halved! 6.2 Mpps against 12.38
> Mpps
>
> > > of
>
> > > expected theoretical maximum for this packet size.
>
> > >
>
> > > That is the issue.
>
> > >
>
> > > Significant performance degradation exists up to 50 bytes of UDP
> payload
>
> > > (96 bytes packet length), where it jumps back to theoretical maximum.
>
> > >
>
> > > What is happening between 80 and 96 bytes packet length?
>
> > >
>
> > > This issue is stable and 100% reproducible. At this point I am not
> sure if
>
> > > it is DPDK or NIC issue. These tests have been performed on Intel(R)
> Eth
>
> > > Svr Bypass Adapter X520-LR2 (X520LR2BP).
>
> > >
>
> > > Is anyone aware of such strange behavior?
>
> > I cannot reproduce the issue using two ports on two different 82599EB
> NICs,
>
> > using 1.7.1 and 1.8.0.
>
> > I always get either same or better linerate as I increase the packet
> size.
>
> >
>
> > Thank you for trying to reproduce the issue.
>
> >
>
> > Actually, have you tried using 1.8.0?
>
> >
>
> > I feel 1.8.0 is little bit immature and might require some post-release
>
> > patching. Even tespmd from this release is not forwarding packets
> properly
>
> > on my setup. It is up and running without visible errors/warnings, TX/RX
>
> > counters are ticking but I can not see any packets at the output.
>
>
>
> This is strange. Without  changing anything, forwarding works perfectly
> for me
>
> (so, RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC is enabled).
>
>
>
> >Please note, both 1.6.0r2 and 1.7.1 releases work (on the same setup)
> out-of-the-box just
>
> > fine with only exception of this mysterious performance drop.
>
> > So it will take some time to figure out what is wrong with dpdk-1.8.0.
>
> > Meanwhile we could focus on stable dpdk-1.7.1.
>
> >
>
> > Managed to get testpmd from dpdk-1.8.0 to work on my setup.
>
> > Unfortunately I had to disable RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC,
>
> > it is new comparing to 1.7.1 and somehow breaks testpmd forwarding. By
> the
>
> > way, simply disabling RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC in
>
> > common_linuxapp config file breaks the build - had to make quick'n'dirty
> fix
>
> > in struct igb_rx_queue as well.
>
> >
>
> > Anyway, issue is still here.
>
> >
>
> > Forwarding 80 bytes packets at 12.4 Mpps.
>
> > Forwarding 81 bytes packets at 7.2 Mpps.
>
> >
>
> > Any ideas?
>
> > As for X520-LR2 NIC - it is dual port bypass adapter with device id
> 155d. I
>
> > believe it should be treated as 82599EB except bypass feature. I put
> bypass
>
> > mode to "normal" in those tests.
>
>
>
> I have used a 82599EB first, and now a X520-SR2. Same results.
>
> I assume that X520-SR2 and X520-LR2 should give similar results
>
> (only thing that is changed is the wavelength, but the controller is the
> same).
>
>
>
It seems I found what was wrong, at least got a hint.

My build server machine type differs from test setup. Until now it was OK
to build DPDK with -march=native.

I found that building dpdk-1.8.0 with explicitly set core-avx-i (snb, ivb)
or bdver2 (amd) machine types almost eliminates performance drop. The same
goes for RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC option issues.

It seems DPDK performance and stability depends on machine type more than I
was expecting.

Thank you for your help.

Alexander

 Pablo
>
> > Alexander
>
> >
>
> >
>
> > Pablo
>
> > >
>
> > > Regards,
>
> > > Alexander Belyakov
>
> >
>
> >
>
>
>
>
>

Re: [dpdk-dev] DPDK testpmd forwarding performace degradation

[De Lara Guarch, Pablo]

> On Tue, Jan 27, 2015 at 10:51 AM, Alexander Belyakov

> <abelyako@gmail.com<mailto:abelyako@gmail.com>> wrote:

>

> Hi Pablo,

>

> On Mon, Jan 26, 2015 at 5:22 PM, De Lara Guarch, Pablo

> <pablo.de.lara.guarch@intel.com<mailto:pablo.de.lara.guarch@intel.com>> wrote:

> Hi Alexander,

>

> > -----Original Message-----

> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Alexander

> Belyakov

> > Sent: Monday, January 26, 2015 10:18 AM

> > To: dev@dpdk.org<mailto:dev@dpdk.org>

> > Subject: [dpdk-dev] DPDK testpmd forwarding performace degradation

> >

> > Hello,

> >

> > recently I have found a case of significant performance degradation for our

> > application (built on top of DPDK, of course). Surprisingly, similar issue

> > is easily reproduced with default testpmd.

> >

> > To show the case we need simple IPv4 UDP flood with variable UDP

> payload

> > size. Saying "packet length" below I mean: Eth header length (14 bytes) +

> > IPv4 header length (20 bytes) + UPD header length (8 bytes) + UDP payload

> > length (variable) + CRC (4 bytes). Source IP addresses and ports are

> selected

> > randomly for each packet.

> >

> > I have used DPDK with revisions 1.6.0r2 and 1.7.1. Both show the same

> issue.

> >

> > Follow "Quick start" guide (http://dpdk.org/doc/quick-start) to build and

> > run testpmd. Enable testpmd forwarding ("start" command).

> >

> > Table below shows measured forwarding performance depending on

> packet

> > length:

> >

> > No. -- UDP payload length (bytes) -- Packet length (bytes) -- Forwarding

> > performance (Mpps) -- Expected theoretical performance (Mpps)

> >

> > 1. 0 -- 64 -- 14.8 -- 14.88

> > 2. 34 -- 80 -- 12.4 -- 12.5

> > 3. 35 -- 81 -- 6.2 -- 12.38 (!)

> > 4. 40 -- 86 -- 6.6 -- 11.79

> > 5. 49 -- 95 -- 7.6 -- 10.87

> > 6. 50 -- 96 -- 10.7 -- 10.78 (!)

> > 7. 60 -- 106 -- 9.4 -- 9.92

> >

> > At line number 3 we have added 1 byte of UDP payload (comparing to

> > previous

> > line) and got forwarding performance halved! 6.2 Mpps against 12.38 Mpps

> > of

> > expected theoretical maximum for this packet size.

> >

> > That is the issue.

> >

> > Significant performance degradation exists up to 50 bytes of UDP payload

> > (96 bytes packet length), where it jumps back to theoretical maximum.

> >

> > What is happening between 80 and 96 bytes packet length?

> >

> > This issue is stable and 100% reproducible. At this point I am not sure if

> > it is DPDK or NIC issue. These tests have been performed on Intel(R) Eth

> > Svr Bypass Adapter X520-LR2 (X520LR2BP).

> >

> > Is anyone aware of such strange behavior?

> I cannot reproduce the issue using two ports on two different 82599EB NICs,

> using 1.7.1 and 1.8.0.

> I always get either same or better linerate as I increase the packet size.

>

> Thank you for trying to reproduce the issue.

>

> Actually, have you tried using 1.8.0?

>

> I feel 1.8.0 is little bit immature and might require some post-release

> patching. Even tespmd from this release is not forwarding packets properly

> on my setup. It is up and running without visible errors/warnings, TX/RX

> counters are ticking but I can not see any packets at the output.



This is strange. Without  changing anything, forwarding works perfectly for me

(so, RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC is enabled).



>Please note, both 1.6.0r2 and 1.7.1 releases work (on the same setup) out-of-the-box just

> fine with only exception of this mysterious performance drop.

> So it will take some time to figure out what is wrong with dpdk-1.8.0.

> Meanwhile we could focus on stable dpdk-1.7.1.

>

> Managed to get testpmd from dpdk-1.8.0 to work on my setup.

> Unfortunately I had to disable RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC,

> it is new comparing to 1.7.1 and somehow breaks testpmd forwarding. By the

> way, simply disabling RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC in

> common_linuxapp config file breaks the build - had to make quick'n'dirty fix

> in struct igb_rx_queue as well.

>

> Anyway, issue is still here.

>

> Forwarding 80 bytes packets at 12.4 Mpps.

> Forwarding 81 bytes packets at 7.2 Mpps.

>

> Any ideas?

> As for X520-LR2 NIC - it is dual port bypass adapter with device id 155d. I

> believe it should be treated as 82599EB except bypass feature. I put bypass

> mode to "normal" in those tests.



I have used a 82599EB first, and now a X520-SR2. Same results.

I assume that X520-SR2 and X520-LR2 should give similar results

(only thing that is changed is the wavelength, but the controller is the same).



Pablo

> Alexander

>

>

> Pablo

> >

> > Regards,

> > Alexander Belyakov

>

>

Re: [dpdk-dev] DPDK testpmd forwarding performace degradation

[Alexander Belyakov]

On Tue, Jan 27, 2015 at 10:51 AM, Alexander Belyakov <abelyako@gmail.com>
wrote:

>
> Hi Pablo,
>
> On Mon, Jan 26, 2015 at 5:22 PM, De Lara Guarch, Pablo <
> pablo.de.lara.guarch@intel.com> wrote:
>
>> Hi Alexander,
>>
>> > -----Original Message-----
>> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Alexander Belyakov
>> > Sent: Monday, January 26, 2015 10:18 AM
>> > To: dev@dpdk.org
>> > Subject: [dpdk-dev] DPDK testpmd forwarding performace degradation
>> >
>> > Hello,
>> >
>> > recently I have found a case of significant performance degradation for
>> our
>> > application (built on top of DPDK, of course). Surprisingly, similar
>> issue
>> > is easily reproduced with default testpmd.
>> >
>> > To show the case we need simple IPv4 UDP flood with variable UDP payload
>> > size. Saying "packet length" below I mean: Eth header length (14 bytes)
>> +
>> > IPv4 header length (20 bytes) + UPD header length (8 bytes) + UDP
>> payload
>> > length (variable) + CRC (4 bytes). Source IP addresses and ports are
>> selected
>> > randomly for each packet.
>> >
>> > I have used DPDK with revisions 1.6.0r2 and 1.7.1. Both show the same
>> issue.
>> >
>> > Follow "Quick start" guide (http://dpdk.org/doc/quick-start) to build
>> and
>> > run testpmd. Enable testpmd forwarding ("start" command).
>> >
>> > Table below shows measured forwarding performance depending on packet
>> > length:
>> >
>> > No. -- UDP payload length (bytes) -- Packet length (bytes) -- Forwarding
>> > performance (Mpps) -- Expected theoretical performance (Mpps)
>> >
>> > 1. 0 -- 64 -- 14.8 -- 14.88
>> > 2. 34 -- 80 -- 12.4 -- 12.5
>> > 3. 35 -- 81 -- 6.2 -- 12.38 (!)
>> > 4. 40 -- 86 -- 6.6 -- 11.79
>> > 5. 49 -- 95 -- 7.6 -- 10.87
>> > 6. 50 -- 96 -- 10.7 -- 10.78 (!)
>> > 7. 60 -- 106 -- 9.4 -- 9.92
>> >
>> > At line number 3 we have added 1 byte of UDP payload (comparing to
>> > previous
>> > line) and got forwarding performance halved! 6.2 Mpps against 12.38 Mpps
>> > of
>> > expected theoretical maximum for this packet size.
>> >
>> > That is the issue.
>> >
>> > Significant performance degradation exists up to 50 bytes of UDP payload
>> > (96 bytes packet length), where it jumps back to theoretical maximum.
>> >
>> > What is happening between 80 and 96 bytes packet length?
>> >
>> > This issue is stable and 100% reproducible. At this point I am not sure
>> if
>> > it is DPDK or NIC issue. These tests have been performed on Intel(R) Eth
>> > Svr Bypass Adapter X520-LR2 (X520LR2BP).
>> >
>> > Is anyone aware of such strange behavior?
>>
>> I cannot reproduce the issue using two ports on two different 82599EB
>> NICs, using 1.7.1 and 1.8.0.
>> I always get either same or better linerate as I increase the packet size.
>>
>
> Thank you for trying to reproduce the issue.
>
>
>> Actually, have you tried using 1.8.0?
>>
>
> I feel 1.8.0 is little bit immature and might require some post-release
> patching. Even tespmd from this release is not forwarding packets properly
> on my setup. It is up and running without visible errors/warnings, TX/RX
> counters are ticking but I can not see any packets at the output. Please
> note, both 1.6.0r2 and 1.7.1 releases work (on the same setup)
> out-of-the-box just fine with only exception of this mysterious performance
> drop.
>
> So it will take some time to figure out what is wrong with dpdk-1.8.0.
> Meanwhile we could focus on stable dpdk-1.7.1.
>
>
Managed to get testpmd from dpdk-1.8.0 to work on my setup. Unfortunately I
had to disable RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC, it is new comparing to
1.7.1 and somehow breaks testpmd forwarding. By the way, simply disabling
RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC in common_linuxapp config file breaks
the build - had to make quick'n'dirty fix in struct igb_rx_queue as well.

Anyway, issue is still here.

Forwarding 80 bytes packets at 12.4 Mpps.
Forwarding 81 bytes packets at 7.2 Mpps.

Any ideas?

As for X520-LR2 NIC - it is dual port bypass adapter with device id 155d. I
> believe it should be treated as 82599EB except bypass feature. I put bypass
> mode to "normal" in those tests.
>
> Alexander
>
>
>>
>> Pablo
>> >
>> > Regards,
>> > Alexander Belyakov
>>
>
>
>

Re: [dpdk-dev] DPDK testpmd forwarding performace degradation

[Stephen Hemminger]

On Mon, 26 Jan 2015 13:17:48 +0300
Alexander Belyakov <abelyako@gmail.com> wrote:

> Hello,
> 
> recently I have found a case of significant performance degradation for our
> application (built on top of DPDK, of course). Surprisingly, similar issue
> is easily reproduced with default testpmd.
> 
> To show the case we need simple IPv4 UDP flood with variable UDP payload
> size. Saying "packet length" below I mean: Eth header length (14 bytes) +
> IPv4 header length (20 bytes) + UPD header length (8 bytes) + UDP payload
> length (variable) + CRC (4 bytes). Source IP addresses and ports are selected
> randomly for each packet.
> 
> I have used DPDK with revisions 1.6.0r2 and 1.7.1. Both show the same issue.
> 
> Follow "Quick start" guide (http://dpdk.org/doc/quick-start) to build and
> run testpmd. Enable testpmd forwarding ("start" command).
> 
> Table below shows measured forwarding performance depending on packet
> length:
> 
> No. -- UDP payload length (bytes) -- Packet length (bytes) -- Forwarding
> performance (Mpps) -- Expected theoretical performance (Mpps)

Did you try using git bisect to identify the problem.

Re: [dpdk-dev] DPDK testpmd forwarding performace degradation

[De Lara Guarch, Pablo]

Hi Alexander,

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Alexander Belyakov
> Sent: Monday, January 26, 2015 10:18 AM
> To: dev@dpdk.org
> Subject: [dpdk-dev] DPDK testpmd forwarding performace degradation
> 
> Hello,
> 
> recently I have found a case of significant performance degradation for our
> application (built on top of DPDK, of course). Surprisingly, similar issue
> is easily reproduced with default testpmd.
> 
> To show the case we need simple IPv4 UDP flood with variable UDP payload
> size. Saying "packet length" below I mean: Eth header length (14 bytes) +
> IPv4 header length (20 bytes) + UPD header length (8 bytes) + UDP payload
> length (variable) + CRC (4 bytes). Source IP addresses and ports are selected
> randomly for each packet.
> 
> I have used DPDK with revisions 1.6.0r2 and 1.7.1. Both show the same issue.
> 
> Follow "Quick start" guide (http://dpdk.org/doc/quick-start) to build and
> run testpmd. Enable testpmd forwarding ("start" command).
> 
> Table below shows measured forwarding performance depending on packet
> length:
> 
> No. -- UDP payload length (bytes) -- Packet length (bytes) -- Forwarding
> performance (Mpps) -- Expected theoretical performance (Mpps)
> 
> 1. 0 -- 64 -- 14.8 -- 14.88
> 2. 34 -- 80 -- 12.4 -- 12.5
> 3. 35 -- 81 -- 6.2 -- 12.38 (!)
> 4. 40 -- 86 -- 6.6 -- 11.79
> 5. 49 -- 95 -- 7.6 -- 10.87
> 6. 50 -- 96 -- 10.7 -- 10.78 (!)
> 7. 60 -- 106 -- 9.4 -- 9.92
> 
> At line number 3 we have added 1 byte of UDP payload (comparing to
> previous
> line) and got forwarding performance halved! 6.2 Mpps against 12.38 Mpps
> of
> expected theoretical maximum for this packet size.
> 
> That is the issue.
> 
> Significant performance degradation exists up to 50 bytes of UDP payload
> (96 bytes packet length), where it jumps back to theoretical maximum.
> 
> What is happening between 80 and 96 bytes packet length?
> 
> This issue is stable and 100% reproducible. At this point I am not sure if
> it is DPDK or NIC issue. These tests have been performed on Intel(R) Eth
> Svr Bypass Adapter X520-LR2 (X520LR2BP).
> 
> Is anyone aware of such strange behavior?

I cannot reproduce the issue using two ports on two different 82599EB NICs, using 1.7.1 and 1.8.0.
I always get either same or better linerate as I increase the packet size.
Actually, have you tried using 1.8.0? 

Pablo
> 
> Regards,
> Alexander Belyakov

[dpdk-dev] DPDK testpmd forwarding performace degradation

[Alexander Belyakov]

Hello,

recently I have found a case of significant performance degradation for our
application (built on top of DPDK, of course). Surprisingly, similar issue
is easily reproduced with default testpmd.

To show the case we need simple IPv4 UDP flood with variable UDP payload
size. Saying "packet length" below I mean: Eth header length (14 bytes) +
IPv4 header length (20 bytes) + UPD header length (8 bytes) + UDP payload
length (variable) + CRC (4 bytes). Source IP addresses and ports are selected
randomly for each packet.

I have used DPDK with revisions 1.6.0r2 and 1.7.1. Both show the same issue.

Follow "Quick start" guide (http://dpdk.org/doc/quick-start) to build and
run testpmd. Enable testpmd forwarding ("start" command).

Table below shows measured forwarding performance depending on packet
length:

No. -- UDP payload length (bytes) -- Packet length (bytes) -- Forwarding
performance (Mpps) -- Expected theoretical performance (Mpps)

1. 0 -- 64 -- 14.8 -- 14.88
2. 34 -- 80 -- 12.4 -- 12.5
3. 35 -- 81 -- 6.2 -- 12.38 (!)
4. 40 -- 86 -- 6.6 -- 11.79
5. 49 -- 95 -- 7.6 -- 10.87
6. 50 -- 96 -- 10.7 -- 10.78 (!)
7. 60 -- 106 -- 9.4 -- 9.92

At line number 3 we have added 1 byte of UDP payload (comparing to previous
line) and got forwarding performance halved! 6.2 Mpps against 12.38 Mpps of
expected theoretical maximum for this packet size.

That is the issue.

Significant performance degradation exists up to 50 bytes of UDP payload
(96 bytes packet length), where it jumps back to theoretical maximum.

What is happening between 80 and 96 bytes packet length?

This issue is stable and 100% reproducible. At this point I am not sure if
it is DPDK or NIC issue. These tests have been performed on Intel(R) Eth
Svr Bypass Adapter X520-LR2 (X520LR2BP).

Is anyone aware of such strange behavior?

Regards,
Alexander Belyakov