Re: [dpdk-users] Dpdk poor performance on virtual machine

[edgar helmut <helmut.edgar100@gmail.com>]

I tried this procedure as well as few others.
at all of the procedures the HugePages_Free or HugePages_Rsvd doesn't
change when creating the guest, though only AnonHugePages increases.
I am struggling with it for a while without real success.
I do suspect that this anonymous hugepages doesn't really make the job.

any idea?


On Tue, Dec 27, 2016 at 8:52 PM Stephen Hemminger <
stephen@networkplumber.org> wrote:

> On Tue, 27 Dec 2016 15:59:08 +0000
> edgar helmut <helmut.edgar100@gmail.com> wrote:
>
> > short explanation for how to read the comparison:
> > first row is packet length
> > throughput is half duplex, means:
> > second row is vm throughput of port 1 to 2 (port 2 to 1 has approximately
> > same throughput) in gbps.
> > third row is host throughput of port 1 to 2 (port 2 to 1 has
> approximately
> > same throughput) in gbps.
> >
> > i.e. on 1500 bytes packet size testpmd delivers ~9.82 gbps from port 1
> to 2
> > and another ~9.82 gbps from port 2 to 1, while at the vm it only delivers
> > ~3.9 gbps for each direction.
> >
> >
> > On Tue, Dec 27, 2016 at 5:52 PM edgar helmut <helmut.edgar100@gmail.com>
> > wrote:
> >
> > > Thanks. That's the document i am following.
> > > For the best i can only ask that the hugepages won't be shared with
> > > others, but it never reserve it from the pre allocated hugepages of the
> > > host.
> > > Did you have a chance to use hugepages for a guest
> > >
> > > as for the interfaces, i am using the virtio/vhost which creates the
> > > macvtap:
> > >     <interface type='direct' managed='yes'>
> > >         <source dev='ens6f0' mode='passthrough'/>
> > >         <model type='virtio'/>
> > >         <driver name='vhost' queues='2'/>
> > >         </driver>
> > >         <address type='pci' domain='0x0000' bus='0x04' slot='0x09'
> > > function='0x0'/>
> > >     </interface>
> > >
> > > The following is a performance comparison host vs. vm using testpmd. as
> > > you can see vm performance is poor.
> > >
> > > (sudo x86_64-native-linuxapp-gcc/app/testpmd -c 0x1f -n 3 -m 1024 --
> > > --coremask=0x1e --portmask=3 -i)
> > >
> > >
> > > 64 128 256 500 800 1000 1500
> > > vm 0.23 0.42 0.75 1.3 2.3 2.7 3.9
> > > host 3.6 6.35 8.3 9.5 9.7 9.8 9.82
> > >
> > > I have to improve it dramatically.
> > >
> > >
> > >
> > > On Mon, Dec 26, 2016 at 2:52 AM Hu, Xuekun <xuekun.hu@intel.com>
> wrote:
> > >
> > > Searching “hugepages” in https://libvirt.org/formatdomain.html
> > >
> > >
> > >
> > > If you are looking for to measure in and out packets through host,
> maybe
> > > you can look at vhost/virtio interface also.
> > >
> > >
> > >
> > > After your testing, if you can report the performace out with macvtap,
> > > that also helps us. J
> > >
> > >
> > >
> > >
> > >
> > > *From:* edgar helmut [mailto:helmut.edgar100@gmail.com]
> > > *Sent:* Saturday, December 24, 2016 11:53 PM
> > >
> > >
> > > *To:* Hu, Xuekun <xuekun.hu@intel.com>
> > > *Cc:* Wiles, Keith <keith.wiles@intel.com>; users@dpdk.org
> > > *Subject:* Re: [dpdk-users] Dpdk poor performance on virtual machine
> > >
> > >
> > >
> > > any idea how to reserve hugepages for a guest (and not
> > > transparent/anonymous hugepages) ?
> > >
> > > i am using libvirt and any backing method I am trying results with
> > > anonymous hugepage.
> > >
> > > disabling the transparent hugepages resulted without any hugepages.
> > >
> > > Thanks
> > >
> > >
> > >
> > > On Sat, Dec 24, 2016 at 10:06 AM edgar helmut <
> helmut.edgar100@gmail.com>
> > > wrote:
> > >
> > > I am looking for a mean to measure in and out packets to and from the
> vm
> > > (without asking the vm itself). While pure passthrough doesn't expose
> an
> > > interface to query for in/out pkts the macvtap exposes such an
> interface.
> > >
> > > As for the anonymous hugepages I was looking for a more flexible method
> > > and I assumed there is no much difference.
> > >
> > > I will make the test with reserved hugepages.
> > >
> > > However is there any knowledge about macvtap performance issues when
> > > delivering 5-6 gbps?
> > >
> > >
> > >
> > > Thanks
> > >
> > >
> > >
> > >
> > >
> > > On 24 Dec 2016 9:06 AM, "Hu, Xuekun" <xuekun.hu@intel.com> wrote:
> > >
> > > Now your setup has a new thing, “macvtap”. I don’t know what’s the
> > > performance of using macvtap. I only know it has much worse perf than
> the
> > > “real” pci pass-through.
> > >
> > >
> > >
> > > I also don’t know why you select such config for your setup, anonymous
> > > huge pages and macvtap. Any specific purpose?
> > >
> > >
> > >
> > > I think you should get a baseline first, then to get how much perf
> dropped
> > > if using anonymous hugepages or macvtap。
> > >
> > > 1.      Baseline: real hugepage + real pci pass-through
> > >
> > > 2.      Anon hugepages vs hugepages
> > >
> > > 3.      Real pci pass-through vs. macvtap
> > >
> > >
> > >
> > > *From:* edgar helmut [mailto:helmut.edgar100@gmail.com]
> > > *Sent:* Saturday, December 24, 2016 3:23 AM
> > > *To:* Hu, Xuekun <xuekun.hu@intel.com>
> > > *Cc:* Wiles, Keith <keith.wiles@intel.com>; users@dpdk.org
> > >
> > >
> > > *Subject:* Re: [dpdk-users] Dpdk poor performance on virtual machine
> > >
> > >
> > >
> > > Hello,
> > >
> > > I changed the setup but still performance are poor :( and I need your
> help
> > > to understand the root cause.
> > >
> > > the setup is (sorry for long description):
> > >
> > > (test equipment is pktgen using dpdk installed on a second physical
> > > machine coonected with 82599 NICs)
> > >
> > > host: Intel(R) Xeon(R) CPU E5-2640 v4 @ 2.40GHz with single socket ,
> > > ubuntu 16.04, with 4 hugepages of 1G each.
> > >
> > > hypervizor (kvm): QEMU emulator version 2.5.0
> > >
> > > guest: same cpu as host, created with 3 vcpus, using ubuntu 16.04
> > >
> > > dpdk: tried 2.2, 16.04, 16.07, 16.11 - using testpmd and 512 pages of
> 2M
> > > each.
> > >
> > > guest total memory is 2G and all of it is backed by the host with
> > > transparent hugepages (I can see the AnonHugePages consumed at guest
> > > creation). This memory includes the 512 hugepages for the testpmd
> > > application.
> > >
> > > I pinned and isolated the guest's vcpus (using kernel option isolcapu),
> > > and could see clearly that the isolation functions well.
> > >
> > >
> > >
> > > 2 x 82599 NICs connected as passthrough using macvtap interfaces to the
> > > guest, so the guest receives and forwards packets from one interface
> to the
> > > second and vice versa.
> > >
> > > at the guest I bind its interfaces using igb_uio.
> > >
> > > the testpmd at guest starts dropping packets at about ~800mbps between
> > > both ports bi-directional using two vcpus for forwarding (one for the
> > > application management and two for forwarding).
> > >
> > > at 1.2 gbps it drops a lot of packets.
> > >
> > > the same testpmd configuration on the host (between both 82599 NICs)
> > > forwards about 5-6gbps on both ports bi-directional.
> > >
> > > I assumed that forwarding ~5-6 gbps between two ports should be
> trivial,
> > > so it will be great if someone can share its configuration for a tested
> > > setup.
> > >
> > > Any further idea will be highly appreciated.
> > >
> > >
> > >
> > > Thanks.
> > >
> > >
> > >
> > > On Sat, Dec 17, 2016 at 2:56 PM edgar helmut <
> helmut.edgar100@gmail.com>
> > > wrote:
> > >
> > > That's what I afraid.
> > >
> > > In fact i need the host to back the entire guest's memory with
> hugepages.
> > >
> > > I will find the way to do that and make the testing again.
> > >
> > >
> > >
> > >
> > >
> > > On 16 Dec 2016 3:14 AM, "Hu, Xuekun" <xuekun.hu@intel.com> wrote:
> > >
> > > You said VM’s memory was 6G, while transparent hugepages was only used
> ~4G
> > > (4360192KB). So some were mapped to 4K pages.
> > >
> > >
> > >
> > > BTW, the memory used by transparent hugepage is not the hugepage you
> > > reserved in kernel boot option.
> > >
> > >
> > >
> > > *From:* edgar helmut [mailto:helmut.edgar100@gmail.com]
> > > *Sent:* Friday, December 16, 2016 1:24 AM
> > > *To:* Hu, Xuekun
> > > *Cc:* Wiles, Keith; users@dpdk.org
> > > *Subject:* Re: [dpdk-users] Dpdk poor performance on virtual machine
> > >
> > >
> > >
> > > in fact the vm was created with 6G RAM, its kernel boot args are
> defined
> > > with 4 hugepages of 1G each, though when starting the vm i noted that
> > > anonhugepages increased.
> > >
> > > The relevant qemu process id is 6074, and the following sums the
> amount of
> > > allocated AnonHugePages:
> > > sudo grep -e AnonHugePages  /proc/6074/smaps | awk  '{ if($2>0) print
> $2}
> > > '|awk '{s+=$1} END {print s}'
> > >
> > > which results with 4360192
> > >
> > > so not all the memory is backed with transparent hugepages though it is
> > > more than the amount of hugepages the guest supposed to boot with.
> > >
> > > How can I be sure that the required 4G hugepages are really allocated?,
> > > and not, for example, only 2G out of the 4G are allocated (and the
> rest 2
> > > are mapping of the default 4K)?
> > >
> > >
> > >
> > > thanks
> > >
> > >
> > >
> > > On Thu, Dec 15, 2016 at 4:33 PM, Hu, Xuekun <xuekun.hu@intel.com>
> wrote:
> > >
> > > Are you sure the anonhugepages size was equal to the total VM's memory
> > > size?
> > > Sometimes, transparent huge page mechanism doesn't grantee the app is
> using
> > > the real huge pages.
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: users [mailto:users-bounces@dpdk.org] On Behalf Of edgar helmut
> > > Sent: Thursday, December 15, 2016 9:32 PM
> > > To: Wiles, Keith
> > > Cc: users@dpdk.org
> > > Subject: Re: [dpdk-users] Dpdk poor performance on virtual machine
> > >
> > > I have one single socket which is Intel(R) Xeon(R) CPU E5-2640 v4 @
> > > 2.40GHz.
> > >
> > > I just made two more steps:
> > > 1. setting iommu=pt for better usage of the igb_uio
> > > 2. using taskset and isolcpu so now it looks like the relevant dpdk
> cores
> > > use dedicated cores.
> > >
> > > It improved the performance though I still see significant difference
> > > between the vm and the host which I can't fully explain.
> > >
> > > any further idea?
> > >
> > > Regards,
> > > Edgar
> > >
> > >
> > > On Thu, Dec 15, 2016 at 2:54 PM, Wiles, Keith <keith.wiles@intel.com>
> > > wrote:
> > >
> > > >
> > > > > On Dec 15, 2016, at 1:20 AM, edgar helmut <
> helmut.edgar100@gmail.com>
> > > > wrote:
> > > > >
> > > > > Hi.
> > > > > Some help is needed to understand performance issue on virtual
> machine.
> > > > >
> > > > > Running testpmd over the host functions well (testpmd forwards 10g
> > > > between
> > > > > two 82599 ports).
> > > > > However same application running on a virtual machine over same
> host
> > > > > results with huge degradation in performance.
> > > > > The testpmd then is not even able to read 100mbps from nic without
> > > drops,
> > > > > and from a profile i made it looks like a dpdk application runs
> more
> > > than
> > > > > 10 times slower than over host…
> > > >
> > > > Not sure I understand the overall setup, but did you make sure the
> > > NIC/PCI
> > > > bus is on the same socket as the VM. If you have multiple sockets on
> your
> > > > platform. If you have to access the NIC across the QPI it could
> explain
> > > > some of the performance drop. Not sure that much drop is this
> problem.
> > > >
> > > > >
> > > > > Setup is ubuntu 16.04 for host and ubuntu 14.04 for guest.
> > > > > Qemu is 2.3.0 (though I tried with a newer as well).
> > > > > NICs are connected to guest using pci passthrough, and guest's cpu
> is
> > > set
> > > > > as passthrough (same as host).
> > > > > On guest start the host allocates transparent hugepages
> (AnonHugePages)
> > > > so
> > > > > i assume the guest memory is backed with real hugepages on the
> host.
> > > > > I tried binding with igb_uio and with uio_pci_generic but both
> results
> > > > with
> > > > > same performance.
> > > > >
> > > > > Due to the performance difference i guess i miss something.
> > > > >
> > > > > Please advise what may i miss here?
> > > > > Is this a native penalty of qemu??
> > > > >
> > > > > Thanks
> > > > > Edgar
>
> Did you setup KVM host to run guest  in huge pages?
>
> https://access.redhat.com/solutions/36741
>