Hi Satish,
There are hard limitations in nova's code, I did not actually used more thant 8
queues:
def _get_max_tap_queues(self):
# NOTE(kengo.sakai): In kernels prior to 3.0,
# multiple queues on a tap interface is not supported.
# In kernels 3.x, the number of queues on a tap interface
# is limited to 8. From 4.0, the number is 256.
# See: https://bugs.launchpad.net/nova/+bug/1570631
kernel_version = int(os.uname()[2].split(".")[0])
if kernel_version <= 2:
return 1
elif kernel_version == 3:
return 8
elif kernel_version == 4:
return 256
else:
return None
> I am currently playing with those setting and trying to generate
traffic with hping3 tools, do you have any tool to test traffic
performance for specially udp style small packets.
Hping3 is good enough to reproduce it, we have app level test tool, but that is
not your case.
> Here i am trying to increase rx_queue_size & tx_queue_size but its not
working somehow. I have tired following.
Since you are not rocky code, it should only works in qemu.conf, maybe check if
this bug[1] affect you.
> Is there a way i can automate this last task to update queue number
action after reboot vm :) otherwise i can use cloud-init to make sure
all VM build with same config.
Cloud-init or rc.local could be the place to do that.
[1] https://bugzilla.redhat.com/show_bug.cgi?id=1541960
Regards,
Liping Mao
在 2018/9/17 04:09，“Satish Patel”<satish....@gmail.com> 写入:
Update on my last email.
I am able to achieve 150kpps with queue=8 and my goal is to do 300kpps
because some of voice application using 300kps.
Here i am trying to increase rx_queue_size & tx_queue_size but its not
working somehow. I have tired following.
1. add rx/tx size in /etc/nova/nova.conf in libvirt section - (didn't
work)
2. add /etc/libvirtd/qemu.conf - (didn't work)
I have try to edit virsh edit <XML> file but somehow my changes not
getting reflected, i did virsh define <XML> after change and hard
reboot guest but no luck.. how do i edit that option in xml if i want
to do that?
On Sun, Sep 16, 2018 at 1:41 PM Satish Patel <satish....@gmail.com> wrote:
>
> I successful reproduce this error with hping3 tool and look like
> multiqueue is our solution :) but i have few question you may have
> answer of that.
>
> 1. I have created two instance (vm1.example.com & vm2.example.com)
>
> 2. I have flood traffic from vm1 using "hping3 vm2.example.com
> --flood" and i have noticed drops on tap interface. ( This is without
> multiqueue)
>
> 3. Enable multiqueue in image and run same test and again got packet
> drops on tap interface ( I didn't update queue on vm2 guest, so
> definitely i was expecting packet drops)
>
> 4. Now i have try to update vm2 queue using ethtool and i got
> following error, I have 15vCPU and i was trying to add 15 queue
>
> [root@bar-mq ~]# ethtool -L eth0 combined 15
> Cannot set device channel parameters: Invalid argument
>
> Then i have tried 8 queue which works.
>
> [root@bar-mq ~]# ethtool -L eth0 combined 8
> combined unmodified, ignoring
> no channel parameters changed, aborting
> current values: tx 0 rx 0 other 0 combined 8
>
> Now i am not seeing any packet drops on tap interface, I have measure
> PPS and i was able to get 160kpps without packet drops.
>
> Question:
>
> 1. why i am not able to add 15 queue? ( is this NIC or driver
limitation?)
> 2. how do i automate "ethtool -L eth0 combined 8" command in instance
> so i don't need to tell my customer to do this manually?
> On Sun, Sep 16, 2018 at 11:53 AM Satish Patel <satish....@gmail.com>
wrote:
> >
> > Hi Liping,
> >
> > >> I think multi queue feature should help.（be careful to make sure the
ethtool update queue number action also did after reboot the vm）.
> >
> > Is there a way i can automate this last task to update queue number
> > action after reboot vm :) otherwise i can use cloud-init to make sure
> > all VM build with same config.
> > On Sun, Sep 16, 2018 at 11:51 AM Satish Patel <satish....@gmail.com>
wrote:
> > >
> > > I am currently playing with those setting and trying to generate
> > > traffic with hping3 tools, do you have any tool to test traffic
> > > performance for specially udp style small packets.
> > >
> > > I am going to share all my result and see what do you feel because i
> > > have noticed you went through this pain :) I will try every single
> > > option which you suggested to make sure we are good before i move
> > > forward to production.
> > > On Sun, Sep 16, 2018 at 11:25 AM Liping Mao (limao) <li...@cisco.com>
wrote:
> > > >
> > > > I think multi queue feature should help.（be careful to make sure
the ethtool update queue number action also did after reboot the vm）.
> > > >
> > > > Numa cpu pin and queue length will be a plus in my exp. You may
need yo have performance test in your situatuon，in my case cpu numa helpped the
app get very stable 720p/1080p transcoding performance. Not sure if your app
get benifit.
> > > >
> > > > You are not using L3，this will let you avoid a lot of performance
issue. And since only two instance with 80kpps packets，so in your case，HW
interface should not be bottleneck too. And your Nexus 5k/7k will not be
bottleneck for sure ;-)
> > > >
> > > >
> > > > Thanks，
> > > > Liping Mao
> > > >
> > > > > 在 2018年9月16日，23:09，Satish Patel <satish....@gmail.com> 写道：
> > > > >
> > > > > Thanks Liping,
> > > > >
> > > > > I am using libvertd 3.9.0 version so look like i am eligible take
> > > > > advantage of that feature. phew!
> > > > >
> > > > > [root@compute-47 ~]# libvirtd -V
> > > > > libvirtd (libvirt) 3.9.0
> > > > >
> > > > > Let me tell you how i am running instance on my openstack, my
compute
> > > > > has 32 core / 32G memory and i have created two instance on
compute
> > > > > node 15vcpu and 14G memory ( two instance using 30 vcpu core, i
have
> > > > > kept 2 core for compute node). on compute node i disabled
overcommit
> > > > > using ratio (1.0)
> > > > >
> > > > > I didn't configure NUMA yet because i wasn't aware of this
feature, as
> > > > > per your last post do you think numa will help to fix this issue?
> > > > > following is my numa view
> > > > >
> > > > > [root@compute-47 ~]# numactl --hardware
> > > > > available: 2 nodes (0-1)
> > > > > node 0 cpus: 0 1 2 3 4 5 6 7 16 17 18 19 20 21 22 23
> > > > > node 0 size: 16349 MB
> > > > > node 0 free: 133 MB
> > > > > node 1 cpus: 8 9 10 11 12 13 14 15 24 25 26 27 28 29 30 31
> > > > > node 1 size: 16383 MB
> > > > > node 1 free: 317 MB
> > > > > node distances:
> > > > > node 0 1
> > > > > 0: 10 20
> > > > > 1: 20 10
> > > > >
> > > > >
> > > > > I am not using any L3 router, i am using provide VLAN network and
> > > > > using Cisco Nexus switch for my L3 function so i am not seeing any
> > > > > bottleneck there.
> > > > >
> > > > > This is the 10G NIC i have on all my compute node, dual 10G port
with
> > > > > bonding (20G)
> > > > >
> > > > > 03:00.0 Ethernet controller: Broadcom Limited NetXtreme II
BCM57810 10
> > > > > Gigabit Ethernet (rev 10)
> > > > > 03:00.1 Ethernet controller: Broadcom Limited NetXtreme II
BCM57810 10
> > > > > Gigabit Ethernet (rev 10)
> > > > >
> > > > >
> > > > >> On Sun, Sep 16, 2018 at 10:50 AM Liping Mao (limao)
<li...@cisco.com> wrote:
> > > > >>
> > > > >> It is still possible to update rx and tx queues length if your
qemu and libvirt version is higher than the version recorded in [3]. （You
should possible to update directly in libvirt configuration if my memory is
correct）
> > > > >>
> > > > >> We also have some similar use case which run audio/vedio
serivcs. They are CPU consuming and have UDP small packets. Another possible
tunning is using CPU pin for the vm. you can use numa awared cpu feature to
get stable cpu performance ，vm network dropped packets sometimes because of the
vm cpu is too busy，with numa cpu it works better performance，our way is similar
with [a]. You need to create flavor with special metadata and dedicated Host
Agg for numa awared VMs. Dedicated CPU is very good for media service. It makes
the CPU performance stable.
> > > > >>
> > > > >> Another packet loss case we get is because of vm kernel, some of
our app are using 32bit OS, that cause memory issue, when traffic larger then
50kpps, it dropped a lot,sometimes,it even crash. In this case, 32bit os can
actually use very limited memory, we have to add swap for the vm. Hope your app
is using 64 bit OS. Because 32 bit could cause tons of trouble.
> > > > >>
> > > > >> BTW,if you are using vrouter on L3, you’d better to move
provider network(no vrouter). I did not tried DVR, but if you are running
without DVR, the L3 node will be bottleneck very quick. Especially default
iptables conntrack is 65535, you will reach to it and drop packet on L3, even
after you tun that value, it still hard to more that 1Mpps for your network
node.
> > > > >>
> > > > >> If your App more than 200kpps per compute node, you may be
better also have a look your physical network driver tx/rx configuration. Most
of the HW default value for tx/rx queues number and length are very poor,you
may start to get packet on eth interface on physical host when rx queue is full.
> > > > >>
> > > > >>
[a]https://redhatstackblog.redhat.com/2015/05/05/cpu-pinning-and-numa-topology-awareness-in-openstack-compute/
> > > > >>
> > > > >> Regards，
> > > > >> Liping Mao
> > > > >>
> > > > >> 在 2018年9月16日，21:18，Satish Patel <satish....@gmail.com> 写道：
> > > > >>
> > > > >> Hi Liping,
> > > > >>
> > > > >> Thank you for your reply,
> > > > >>
> > > > >> We notice packet drops during high load, I did try txqueue and
didn't help so I believe I am going to try miltiqueue.
> > > > >>
> > > > >> For SRIOV I have to look if I have support in my nic.
> > > > >>
> > > > >> We are using queens so I think queue size option not possible :(
> > > > >>
> > > > >> We are using voip application and traffic is udp so our pps rate
is 60k to 80k per vm instance.
> > > > >>
> > > > >> I will share my result as soon as I try multiqueue.
> > > > >>
> > > > >>
> > > > >>
> > > > >> Sent from my iPhone
> > > > >>
> > > > >> On Sep 16, 2018, at 2:27 AM, Liping Mao (limao)
<li...@cisco.com> wrote:
> > > > >>
> > > > >>
> > > > >> Hi Satish,
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> Did your packet loss happen always or it only happened when
heavy load?
> > > > >>
> > > > >>
> > > > >> AFAIK, if you do not tun anything, the vm tap can process about
50kpps before the tap device start to drop packets.
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> If it happened in heavy load, couple of things you can try:
> > > > >>
> > > > >>
> > > > >> 1) increase tap queue length, usually the default value is 500,
you can try larger. (seems like you already tried)
> > > > >>
> > > > >>
> > > > >> 2) Try to use virtio multi queues feature , see [1]. Virtio use
one queue for rx/tx in vm, with this feature you can get more queues. You can
check
> > > > >>
> > > > >>
> > > > >> 3) In rock version, you can use [2] to increase virtio queue
size, the default queues size is 256/512, you may increase it to 1024, this
would help to increase pps of the tap device.
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> If all these things can not get your network performance
requirement, you may need to move to use dpdk / sriov stuff to get more vm
performance.
> > > > >>
> > > > >>
> > > > >> I did not actually used them in our env, you may refer to [3]
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> [1]
https://specs.openstack.org/openstack/nova-specs/specs/liberty/implemented/libvirt-virtiomq.html
> > > > >>
> > > > >>
> > > > >> [2]
https://specs.openstack.org/openstack/nova-specs/specs/rocky/implemented/libvirt-virtio-set-queue-sizes.html
> > > > >>
> > > > >>
> > > > >> [3]
https://docs.openstack.org/ocata/networking-guide/config-sriov.html
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> Regards,
> > > > >>
> > > > >>
> > > > >> Liping Mao
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> 在 2018/9/16 13:07，“Satish Patel”<satish....@gmail.com> 写入:
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> [root@compute-33 ~]# ifconfig tap5af7f525-5f | grep -i drop
> > > > >>
> > > > >>
> > > > >> RX errors 0 dropped 0 overruns 0 frame 0
> > > > >>
> > > > >>
> > > > >> TX errors 0 dropped 2528788837 overruns 0 carrier 0
collisions 0
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> Noticed tap interface dropping TX packets and even after
increasing
> > > > >>
> > > > >>
> > > > >> txqueue from 1000 to 10000 nothing changed, still getting packet
> > > > >>
> > > > >>
> > > > >> drops.
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> On Sat, Sep 15, 2018 at 4:22 PM Satish Patel
<satish....@gmail.com> wrote:
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> Folks,
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> I need some advice or suggestion to find out what is going on
with my
> > > > >>
> > > > >>
> > > > >> network, we have notice high packet loss on openstack instance
and not
> > > > >>
> > > > >>
> > > > >> sure what is going on, same time if i check on host machine and
it has
> > > > >>
> > > > >>
> > > > >> zero packet loss.. this is what i did for test...
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> ping 8.8.8.8
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> from instance: 50% packet loss
> > > > >>
> > > > >>
> > > > >> from compute host: 0% packet loss
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> I have disabled TSO/GSO/SG setting on physical compute node but
still
> > > > >>
> > > > >>
> > > > >> getting packet loss.
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> We have 10G NIC on our network, look like something related to
tap
> > > > >>
> > > > >>
> > > > >> interface setting..
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >> _______________________________________________
> > > > >>
> > > > >>
> > > > >> Mailing list:
http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
> > > > >>
> > > > >>
> > > > >> Post to : openstack@lists.openstack.org
> > > > >>
> > > > >>
> > > > >> Unsubscribe :
http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
> > > > >>
> > > > >>
> > > > >>
> > > > >>
> > > > >>
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