Hello Everyone,
I''m using sar to monitor network throughput in a paravirtualized DomU
and
I''m seeing some odd values.
For example, if I run iperf on a 100 MBps network with another machine as
the client and either dom0 or domU as the server, I get the same results:
DomU$ iperf -s
[ 4] local 192.168.0.1 port 5001 connected with 10.20.129.175 port 37766
[ ID] Interval Transfer Bandwidth
[ 4] 0.0-10.1 sec 114 MBytes 94.1 Mbits/sec
Dom0$ iperf -s
[ 4] local 10.20.129.178 port 5001 connected with 10.20.129.175 port 58763
[ ID] Interval Transfer Bandwidth
[ 4] 0.0-10.1 sec 113 MBytes 94.1 Mbits/sec
But when measure the throughput with sar while running iperf, the results
are wrong in DomU:
DomU$ sar -n DEV 1 15
15:24:37 IFACE rxpck/s txpck/s rxkB/s txkB/s rxcmp/s
txcmp/s rxmcst/s
15:24:38 eth0 3177.30 1591.41 4651.67 102.58 0.00 0.00
0.00
15:24:39 eth0 5641.67 2822.22 8264.16 181.90 0.00 0.00
0.00
15:24:40 eth0 5684.62 2840.56 8327.07 183.08 0.00 0.00
0.00
15:24:41 eth0 5722.54 2856.34 8382.62 184.10 0.00 0.00
0.00
15:24:42 eth0 5684.62 2825.17 8327.07 182.09 0.00 0.00
0.00
15:24:43 eth0 5682.52 2843.36 8324.00 183.26 0.00 0.00
0.00
15:24:44 eth0 5721.83 2857.04 8381.59 184.15 0.00 0.00
0.00
15:24:45 eth0 5764.54 2878.01 8444.15 185.50 0.00 0.00
0.00
15:24:46 eth0 5641.67 2808.33 8264.16 181.01 0.00 0.00
0.00
15:24:47 eth0 5802.86 2892.14 8500.28 186.41 0.00 0.00
0.00
15:24:48 eth0 2343.27 1171.35 3430.90 75.50 0.00 0.00
0.00
15:24:49 eth0 0.00 0.00 0.00 0.00 0.00
0.00 0.00
15:24:50 eth0 0.00 0.00 0.00 0.00 0.00 0.00
0.00
15:24:51 eth0 0.00 0.00 0.00 0.00 0.00 0.00
0.00
15:24:52 eth0 0.50 0.50 0.01 0.02 0.00 0.00
0.00
Average: eth0 3410.19 1702.32 4995.05 109.72 0.00 0.00
0.00
During the test, sar gives roughly 8,5MB/s in rxkB/s, while it should be
11,76MB/s (94Mbps), as measured by iperf.
When I run the same measurements in Dom0 I get far better results:
15:29:02 IFACE rxpck/s txpck/s rxkB/s txkB/s rxcmp/s
txcmp/s rxmcst/s
15:29:02 eth0 20,00 0,00 2,38 0,00 0,00 0,00
0,00
15:29:03 eth0 5856,00 2938,00 8667,55 200,89 0,00
0,00 0,00
15:29:04 eth0 8125,00 4069,00 12029,87 278,15 0,00
0,00 0,00
15:29:05 eth0 8145,00 4073,00 12066,25 278,43 0,00
0,00 0,00
15:29:06 eth0 8121,00 4063,00 12027,94 277,74 0,00
0,00 0,00
15:29:07 eth0 8150,00 4055,00 12065,41 277,20 0,00
0,00 0,00
15:29:08 eth0 8122,00 4064,00 12029,42 277,81 0,00
0,00 0,00
15:29:09 eth0 8147,00 4079,00 12063,73 278,77 0,00
0,00 0,00
15:29:10 eth0 8123,00 4064,00 12029,34 277,88 0,00
0,00 0,00
15:29:11 eth0 8155,00 4096,00 12066,30 280,00 0,00
0,00 0,00
15:29:12 eth0 8129,00 4111,00 12029,02 281,03 0,00
0,00 0,00
15:29:13 eth0 3213,00 1631,00 4741,51 111,49 0,00
0,00 0,00
15:29:14 eth0 17,00 0,00 1,88 0,00
0,00 0,00 0,00
15:29:15 eth0 12,00 0,00 1,46 0,00
0,00 0,00 0,00
15:29:16 eth0 19,00 0,00 2,44 0,00
0,00 0,00 0,00
Average: eth0 5490,27 2749,53 8121,63 187,96 0,00
0,00 0,00
Has anyone seen something like this?
DomU executes a Debian Squeeze 64 bits OS. Dom0 is provided by Xen 4.0.1.
Thanks,
Ricardo José Pfitscher
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Ricardo Jose Pfitscher
2012-Nov-09 12:06 UTC
Re: sar incorrect network measurement in DomU
Noone? 2012/11/7 Ricardo Jose Pfitscher <ricardo.pfitscher@gmail.com>> Hello Everyone, > > I''m using sar to monitor network throughput in a paravirtualized DomU and > I''m seeing some odd values. > > For example, if I run iperf on a 100 MBps network with another machine as > the client and either dom0 or domU as the server, I get the same results: > > DomU$ iperf -s > [ 4] local 192.168.0.1 port 5001 connected with 10.20.129.175 port 37766 > [ ID] Interval Transfer Bandwidth > [ 4] 0.0-10.1 sec 114 MBytes 94.1 Mbits/sec > > Dom0$ iperf -s > [ 4] local 10.20.129.178 port 5001 connected with 10.20.129.175 port 58763 > [ ID] Interval Transfer Bandwidth > [ 4] 0.0-10.1 sec 113 MBytes 94.1 Mbits/sec > > But when measure the throughput with sar while running iperf, the results > are wrong in DomU: > > DomU$ sar -n DEV 1 15 > > 15:24:37 IFACE rxpck/s txpck/s rxkB/s txkB/s rxcmp/s > txcmp/s rxmcst/s > 15:24:38 eth0 3177.30 1591.41 4651.67 102.58 0.00 > 0.00 0.00 > 15:24:39 eth0 5641.67 2822.22 8264.16 181.90 0.00 > 0.00 0.00 > 15:24:40 eth0 5684.62 2840.56 8327.07 183.08 0.00 > 0.00 0.00 > 15:24:41 eth0 5722.54 2856.34 8382.62 184.10 0.00 > 0.00 0.00 > 15:24:42 eth0 5684.62 2825.17 8327.07 182.09 0.00 > 0.00 0.00 > 15:24:43 eth0 5682.52 2843.36 8324.00 183.26 0.00 > 0.00 0.00 > 15:24:44 eth0 5721.83 2857.04 8381.59 184.15 0.00 > 0.00 0.00 > 15:24:45 eth0 5764.54 2878.01 8444.15 185.50 0.00 > 0.00 0.00 > 15:24:46 eth0 5641.67 2808.33 8264.16 181.01 0.00 > 0.00 0.00 > 15:24:47 eth0 5802.86 2892.14 8500.28 186.41 0.00 > 0.00 0.00 > 15:24:48 eth0 2343.27 1171.35 3430.90 75.50 0.00 > 0.00 0.00 > 15:24:49 eth0 0.00 0.00 0.00 0.00 0.00 > 0.00 0.00 > 15:24:50 eth0 0.00 0.00 0.00 0.00 0.00 > 0.00 0.00 > 15:24:51 eth0 0.00 0.00 0.00 0.00 0.00 > 0.00 0.00 > 15:24:52 eth0 0.50 0.50 0.01 0.02 0.00 > 0.00 0.00 > Average: eth0 3410.19 1702.32 4995.05 109.72 0.00 > 0.00 0.00 > > During the test, sar gives roughly 8,5MB/s in rxkB/s, while it should be > 11,76MB/s (94Mbps), as measured by iperf. > > When I run the same measurements in Dom0 I get far better results: > > 15:29:02 IFACE rxpck/s txpck/s rxkB/s txkB/s rxcmp/s > txcmp/s rxmcst/s > 15:29:02 eth0 20,00 0,00 2,38 0,00 0,00 > 0,00 0,00 > 15:29:03 eth0 5856,00 2938,00 8667,55 200,89 0,00 > 0,00 0,00 > 15:29:04 eth0 8125,00 4069,00 12029,87 278,15 0,00 > 0,00 0,00 > 15:29:05 eth0 8145,00 4073,00 12066,25 278,43 0,00 > 0,00 0,00 > 15:29:06 eth0 8121,00 4063,00 12027,94 277,74 0,00 > 0,00 0,00 > 15:29:07 eth0 8150,00 4055,00 12065,41 277,20 0,00 > 0,00 0,00 > 15:29:08 eth0 8122,00 4064,00 12029,42 277,81 0,00 > 0,00 0,00 > 15:29:09 eth0 8147,00 4079,00 12063,73 278,77 0,00 > 0,00 0,00 > 15:29:10 eth0 8123,00 4064,00 12029,34 277,88 0,00 > 0,00 0,00 > 15:29:11 eth0 8155,00 4096,00 12066,30 280,00 0,00 > 0,00 0,00 > 15:29:12 eth0 8129,00 4111,00 12029,02 281,03 0,00 > 0,00 0,00 > 15:29:13 eth0 3213,00 1631,00 4741,51 111,49 0,00 > 0,00 0,00 > 15:29:14 eth0 17,00 0,00 1,88 0,00 > 0,00 0,00 0,00 > 15:29:15 eth0 12,00 0,00 1,46 0,00 > 0,00 0,00 0,00 > 15:29:16 eth0 19,00 0,00 2,44 0,00 > 0,00 0,00 0,00 > Average: eth0 5490,27 2749,53 8121,63 187,96 0,00 > 0,00 0,00 > > Has anyone seen something like this? > > DomU executes a Debian Squeeze 64 bits OS. Dom0 is provided by Xen 4.0.1. > > Thanks, > > Ricardo José Pfitscher > > > >-- Ricardo José Pfitscher _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users