|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Poor network performance between DomU with multiqueue support
Thanks for your reply, Wei.
I do the following testing just now and found the results as follows:
There are three DomUs (4U4G) are running on Host A (6U6G) and one DomU (4U4G)
is running on Host B (6U6G), I send packets from three DomUs to the DomU on
Host B simultaneously.
1. The "top" output of Host B as follows:
top - 09:42:11 up 1:07, 2 users, load average: 2.46, 1.90, 1.47
Tasks: 173 total, 4 running, 169 sleeping, 0 stopped, 0 zombie
%Cpu0 : 0.0 us, 0.0 sy, 0.0 ni, 97.3 id, 0.0 wa, 0.0 hi, 0.8 si, 1.9 st
%Cpu1 : 0.0 us, 27.0 sy, 0.0 ni, 63.1 id, 0.0 wa, 0.0 hi, 9.5 si, 0.4 st
%Cpu2 : 0.0 us, 90.0 sy, 0.0 ni, 8.3 id, 0.0 wa, 0.0 hi, 1.7 si, 0.0 st
%Cpu3 : 0.4 us, 1.4 sy, 0.0 ni, 95.4 id, 0.0 wa, 0.0 hi, 1.4 si, 1.4 st
%Cpu4 : 0.0 us, 60.2 sy, 0.0 ni, 39.5 id, 0.0 wa, 0.0 hi, 0.3 si, 0.0 st
%Cpu5 : 0.0 us, 2.8 sy, 0.0 ni, 89.4 id, 0.0 wa, 0.0 hi, 6.9 si, 0.9 st
KiB Mem: 4517144 total, 3116480 used, 1400664 free, 876 buffers
KiB Swap: 2103292 total, 0 used, 2103292 free. 2374656 cached Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
7440 root 20 0 0 0 0 R 71.10 0.000 8:15.38
vif4.0-q3-guest
7434 root 20 0 0 0 0 R 59.14 0.000 9:00.58
vif4.0-q0-guest
18 root 20 0 0 0 0 R 33.89 0.000 2:35.06
ksoftirqd/2
28 root 20 0 0 0 0 S 20.93 0.000 3:01.81 ksoftirqd/4
As shown above, only two netback related processes (vif4.0-*) are running with
high cpu usage, and the other 2 netback processes are idle. The "ps" result of
vif4.0-* processes as follows:
root 7434 50.5 0.0 0 0 ? R 09:23 11:29
[vif4.0-q0-guest]
root 7435 0.0 0.0 0 0 ? S 09:23 0:00
[vif4.0-q0-deall]
root 7436 0.0 0.0 0 0 ? S 09:23 0:00
[vif4.0-q1-guest]
root 7437 0.0 0.0 0 0 ? S 09:23 0:00
[vif4.0-q1-deall]
root 7438 0.0 0.0 0 0 ? S 09:23 0:00
[vif4.0-q2-guest]
root 7439 0.0 0.0 0 0 ? S 09:23 0:00
[vif4.0-q2-deall]
root 7440 48.1 0.0 0 0 ? R 09:23 10:55
[vif4.0-q3-guest]
root 7441 0.0 0.0 0 0 ? S 09:23 0:00
[vif4.0-q3-deall]
root 9724 0.0 0.0 9244 1520 pts/0 S+ 09:46 0:00 grep
--color=auto
2. The "rx" related content in /proc/interupts in receiver DomU (on Host B):
73: 2 0 2925405 0
xen-dyn-event eth0-q0-rx
75: 43 93 0 118
xen-dyn-event eth0-q1-rx
77: 2 3376 14 1983
xen-dyn-event eth0-q2-rx
79: 2414666 0 9 0
xen-dyn-event eth0-q3-rx
As shown above, it seems like that only q0 and q3 handles the interrupt
triggered by packet receving.
Any advise? Thanks.
----------
zhangleiqiang (Trump)
Best Regards
> -----Original Message-----
> From: Wei Liu [mailto:wei.liu2@xxxxxxxxxx]
> Sent: Tuesday, December 02, 2014 8:12 PM
> To: Zhangleiqiang (Trump)
> Cc: Wei Liu; zhangleiqiang; xen-devel@xxxxxxxxxxxxx; Luohao (brian); Xiaoding
> (B); Yuzhou (C); Zhuangyuxin
> Subject: Re: [Xen-devel] Poor network performance between DomU with
> multiqueue support
>
> On Tue, Dec 02, 2014 at 11:50:59AM +0000, Zhangleiqiang (Trump) wrote:
> > > -----Original Message-----
> > > From: xen-devel-bounces@xxxxxxxxxxxxx
> > > [mailto:xen-devel-bounces@xxxxxxxxxxxxx] On Behalf Of Wei Liu
> > > Sent: Tuesday, December 02, 2014 7:02 PM
> > > To: zhangleiqiang
> > > Cc: wei.liu2@xxxxxxxxxx; xen-devel@xxxxxxxxxxxxx
> > > Subject: Re: [Xen-devel] Poor network performance between DomU with
> > > multiqueue support
> > >
> > > On Tue, Dec 02, 2014 at 04:30:49PM +0800, zhangleiqiang wrote:
> > > > Hi, all
> > > > I am testing the performance of xen netfront-netback driver
> > > > that with
> > > multi-queues support. The throughput from domU to remote dom0 is
> > > 9.2Gb/s, but the throughput from domU to remote domU is only
> > > 3.6Gb/s, I think the bottleneck is the throughput from dom0 to local
> > > domU. However, we have done some testing and found the throughput
> > > from dom0 to local domU is 5.8Gb/s.
> > > > And if we send packets from one DomU to other 3 DomUs on
> > > > different
> > > host simultaneously, the sum of throughout can reach 9Gbps. It seems
> > > like the bottleneck is the receiver?
> > > > After some analysis, I found that even the max_queue of
> > > > netfront/back
> > > is set to 4, there are some strange results as follows:
> > > > 1. In domU, only one rx queue deal with softirq
> > >
> > > Try to bind irq to different vcpus?
> >
> > Do you mean we try to bind irq to different vcpus in DomU? I will try it
> > now.
> >
>
> Yes. Given the fact that you have two backend threads running while only one
> DomU vcpu is busy, it smells like misconfiguration in DomU.
>
> If this phenomenon persists after correctly binding irqs, you might want to
> check traffic is steering correctly to different queues.
>
> > >
> > > > 2. In dom0, only two netback queues process are scheduled,
> > > > other two
> > > process aren't scheduled.
> > >
> > > How many Dom0 vcpu do you have? If it only has two then there will
> > > only be two processes running at a time.
> >
> > Dom0 has 6 vcpus, and 6G memory. There are only one DomU running in
> Dom0 and so four netback processes are running in Dom0 (because the
> max_queue param of netback kernel module is set to 4).
> > The phenomenon is that only 2 of these four netback process were running
> with about 70% cpu usage, and another two use little CPU.
> > Is there a hash algorithm to determine which netback process to handle the
> input packet?
> >
>
> I think that's whatever default algorithm Linux kernel is using.
>
> We don't currently support other algorithms.
>
> Wei.
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |