Re: [dpdk-dev] L2fwd Performance issue with Virtual Machine

[Selvaganapathy Chidambaram <selvaganapathyc@gmail.com>]

Thanks Rashmin for your time and help!

So it looks like with the given hardware config, we could probably only
achieve around 8 Gbps in VM without using SRIOV. Once DPDK is used in
vSwitch design, we could gain more performance.


Thanks,
Selvaganapathy.C.


On Fri, Oct 4, 2013 at 11:02 AM, Patel, Rashmin N <rashmin.n.patel@intel.com
> wrote:

> Correction: "you would NOT get optimal performance benefit having PMD"
>
> Thanks,
> Rashmin
> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Patel, Rashmin N
> Sent: Friday, October 04, 2013 10:47 AM
> To: Selvaganapathy Chidambaram
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] L2fwd Performance issue with Virtual Machine
>
> Hi,
>
> If you are not using SRIOV or direct device assignment to VM, your traffic
> hits vSwitch(via vmware native ixgbe driver and network stack) in the ESX
> and switched to your E1000/VMXNET3 interface connected to a VM. The vSwitch
> is not optimized for PMD at present so you would get optimal performance
> benefit having PMD, I believe.
>
> For the RSS front, I would say you won't see much difference with RSS
> enabled for 1500 bytes frames. In fact, core is capable of handling such
> traffic in VM, but the bottleneck is in ESXi software switching layer,
> that's what my initial research shows across multiple hypervisors.
>
> Thanks,
> Rashmin
>
> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Selvaganapathy
> Chidambaram
> Sent: Thursday, October 03, 2013 2:39 PM
> To: dev@dpdk.org
> Subject: [dpdk-dev] L2fwd Performance issue with Virtual Machine
>
> Hello Everyone,
>
> I have tried to run DPDK sample application l2fwd(modified to support
> multiple queues) in my ESX Virtual Machine. I see that performance is not
> scaling with cores. [My apologies for the long email]
>
> *Setup:*
>
> Connected VM to two ports of Spirent with 10Gig link. Sent 10 Gig traffic
> of L3 packet of length 1500 bytes (with four different flows) from Spirent
> through one port and received at the second port. Also sent traffic from
> reverse direction so that net traffic is 20 Gbps. Haven't enabled SR-IOV or
>  Direct path I/O.
>
> *Emulated Driver:*
>
> With default emulated driver, I got 7.3 Gbps for 1 core. Adding multiple
> cores did not improve the performance. On debugging I noticed that function
> eth_em_infos_get() says RSS is not supported.
>
> *vmxnet3_usermap:*
>
> Then I tried extension vmxnet3_usermap and got 8.7 Gbps for 1 core. Again
> adding another core did not help. On debugging, I noticed that in vmxnet3
> kernel driver (in function vmxnet3_probe_device) , RSS is disabled if *
> adapter->is_shm* is non zero. In our case, its
> adapter->VMXNET3_SHM_USERMAP_DRIVER
> which is non zero.
>
> Before trying to enable it, I would like to know if there is any known
> limitation why RSS is not enabled in both the drivers. Please help me
> understand.
>
> *Hardware Configuration:*
> Hardware          : Intel Xeon 2.4 Ghz 4 CPUs
> Hyperthreading  : No
> RAM                 : 16 GB
> Hypervisor         : ESXi 5.1
> Ethernet            : Intel 82599EB 10 Gig SFP
>
>
> Guest VM         : 2 vCPU, 2 GB RAM
> GuestOS          : Centos 6.2 32 bit
>
> Thanks in advance for your time and help!!!
>
> Thanks,
> Selva.
>