* About ping latency in SR-IOV
@ 2010-10-29 8:31 XiaYubin
2010-10-29 21:58 ` Rose, Gregory V
0 siblings, 1 reply; 2+ messages in thread
From: XiaYubin @ 2010-10-29 8:31 UTC (permalink / raw)
To: Rose, Gregory V, Dong, Eddie; +Cc: xen-devel
Hi, Greg, Eddie,
I found that in SR-IOV + HVM environment, ping latency depends on ping interval.
The NIC is Intel 82576 (1000Mbps), server uses xen-4.0.1, domain-0 is
kernel-2.6.32
and HVM is kernel-2.6.31. The server and client are connected through
a 1000Mbps switch.
The data is as following:
# ping -i 1 192.168.0.21
PING 192.168.0.21 (192.168.0.21) 56(84) bytes of data.
64 bytes from 192.168.0.21: icmp_seq=1 ttl=64 time=0.117 ms
64 bytes from 192.168.0.21: icmp_seq=2 ttl=64 time=0.100 ms
64 bytes from 192.168.0.21: icmp_seq=3 ttl=64 time=0.102 ms
64 bytes from 192.168.0.21: icmp_seq=4 ttl=64 time=0.100 ms
64 bytes from 192.168.0.21: icmp_seq=5 ttl=64 time=0.105 ms
--- 192.168.0.21 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 3998ms
rtt min/avg/max/mdev = 0.100/0.104/0.117/0.014 ms
# ping -i 0 192.168.0.21
PING 192.168.0.21 (192.168.0.21) 56(84) bytes of data.
64 bytes from 192.168.0.21: icmp_seq=1 ttl=64 time=0.114 ms
64 bytes from 192.168.0.21: icmp_seq=2 ttl=64 time=0.418 ms
64 bytes from 192.168.0.21: icmp_seq=3 ttl=64 time=0.455 ms
64 bytes from 192.168.0.21: icmp_seq=4 ttl=64 time=0.456 ms
64 bytes from 192.168.0.21: icmp_seq=5 ttl=64 time=0.455 ms
--- 192.168.0.21 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 1ms
rtt min/avg/max/mdev = 0.114/0.379/0.456/0.135 ms, ipg/ewma 0.400/0.252 ms
The ping latency of PF (in domain-0) is about 0.08ms in both tests.
Is this caused by something related to interrupt throttle configuration?
If so, can we adjust its threshold?
Thanks!
--
Yubin
^ permalink raw reply [flat|nested] 2+ messages in thread
* RE: About ping latency in SR-IOV
2010-10-29 8:31 About ping latency in SR-IOV XiaYubin
@ 2010-10-29 21:58 ` Rose, Gregory V
0 siblings, 0 replies; 2+ messages in thread
From: Rose, Gregory V @ 2010-10-29 21:58 UTC (permalink / raw)
To: XiaYubin, Dong, Eddie; +Cc: xen-devel
Yes, it is dependent on the Interrupt Throttling setting. Use modinfo on the driver or check the readme for more information on how to use the module parameter.
- Greg
> -----Original Message-----
> From: XiaYubin [mailto:xiayubin@gmail.com]
> Sent: Friday, October 29, 2010 1:31 AM
> To: Rose, Gregory V; Dong, Eddie
> Cc: xen-devel@lists.xensource.com
> Subject: About ping latency in SR-IOV
>
> Hi, Greg, Eddie,
>
> I found that in SR-IOV + HVM environment, ping latency depends on ping
> interval.
>
> The NIC is Intel 82576 (1000Mbps), server uses xen-4.0.1, domain-0 is
> kernel-2.6.32
> and HVM is kernel-2.6.31. The server and client are connected through
> a 1000Mbps switch.
>
> The data is as following:
>
> # ping -i 1 192.168.0.21
>
> PING 192.168.0.21 (192.168.0.21) 56(84) bytes of data.
> 64 bytes from 192.168.0.21: icmp_seq=1 ttl=64 time=0.117 ms
> 64 bytes from 192.168.0.21: icmp_seq=2 ttl=64 time=0.100 ms
> 64 bytes from 192.168.0.21: icmp_seq=3 ttl=64 time=0.102 ms
> 64 bytes from 192.168.0.21: icmp_seq=4 ttl=64 time=0.100 ms
> 64 bytes from 192.168.0.21: icmp_seq=5 ttl=64 time=0.105 ms
>
> --- 192.168.0.21 ping statistics ---
> 5 packets transmitted, 5 received, 0% packet loss, time 3998ms
> rtt min/avg/max/mdev = 0.100/0.104/0.117/0.014 ms
>
> # ping -i 0 192.168.0.21
>
> PING 192.168.0.21 (192.168.0.21) 56(84) bytes of data.
> 64 bytes from 192.168.0.21: icmp_seq=1 ttl=64 time=0.114 ms
> 64 bytes from 192.168.0.21: icmp_seq=2 ttl=64 time=0.418 ms
> 64 bytes from 192.168.0.21: icmp_seq=3 ttl=64 time=0.455 ms
> 64 bytes from 192.168.0.21: icmp_seq=4 ttl=64 time=0.456 ms
> 64 bytes from 192.168.0.21: icmp_seq=5 ttl=64 time=0.455 ms
>
> --- 192.168.0.21 ping statistics ---
> 5 packets transmitted, 5 received, 0% packet loss, time 1ms
> rtt min/avg/max/mdev = 0.114/0.379/0.456/0.135 ms, ipg/ewma 0.400/0.252 ms
>
> The ping latency of PF (in domain-0) is about 0.08ms in both tests.
> Is this caused by something related to interrupt throttle configuration?
> If so, can we adjust its threshold?
>
> Thanks!
>
> --
> Yubin
^ permalink raw reply [flat|nested] 2+ messages in thread
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