Re: [Xen-API] Flood test with xen/openvswitch

[George Shuklin <george.shuklin@xxxxxxxxx>]

temporary solution: add more active cpus to dom0.
echo 1 >/sys/devices/system/cpu/cpu1/online
echo 1 >/sys/devices/system/cpu/cpu2/online
echo 1 >/sys/devices/system/cpu/cpu3/online

Ð ÐÑ., 07/09/2011 Ð 13:29 +0200, SÃbastien Riccio ÐÐÑÐÑ:
> Hi,
> 
> I just did a test to see how openvswitch handle a flood from a virtual 
> machine on a xen
> host using it as the networking layer.
> 
> I just issued a :
> 
> vm1# hping3  -S -L 0 -p 80 -i u100 192.168.1.1
> 
> options I used are:
> -S set SYN tcp flag
> -L set ACK tcp flag
> -p destination port
> -i u100 = interval between packets in micro seconds
> 
> This results in a cpu usage up to 97% by the ovs-vswitchd process in the 
> dom0.
> Letting it go for a few minutes turns the whole xen host unresponsive to 
> network access
> and must then be accessed from the local console.
> 
> Is that an excepted behavior ? I know the test is quite agressive but 
> any customer could issue such a flood
> and render the whole host unreachable. Are there workarounds ?
> 
> Thanks for your help.
> 
> Best regards,
> SÃbastien
> 
> part of the openvswitch logs when issuing the flood:
> 
> Sep 07 13:13:26|01523|poll_loop|WARN|wakeup due to [POLLIN] on fd 18 
> (NETLINK_GENERIC<->NETLINK_GENERIC) at ../lib/netlink-socket.c:668 (85% 
> CPU usage)
> Sep 07 13:13:26|01524|poll_loop|WARN|wakeup due to [POLLIN] on fd 21 
> (NETLINK_GENERIC<->NETLINK_GENERIC) at ../lib/netlink-socket.c:668 (85% 
> CPU usage)
> Sep 07 13:13:27|01525|poll_loop|WARN|Dropped 5136 log messages in last 1 
> seconds (most recently, 1 seconds ago) due to excessive rate
> Sep 07 13:13:27|01526|poll_loop|WARN|wakeup due to [POLLIN] on fd 18 
> (NETLINK_GENERIC<->NETLINK_GENERIC) at ../lib/netlink-socket.c:668 (85% 
> CPU usage)
> Sep 07 13:13:27|01527|poll_loop|WARN|wakeup due to [POLLIN] on fd 21 
> (NETLINK_GENERIC<->NETLINK_GENERIC) at ../lib/netlink-socket.c:668 (85% 
> CPU usage)
> Sep 07 13:13:28|01528|poll_loop|WARN|Dropped 5815 log messages in last 1 
> seconds (most recently, 1 seconds ago) due to excessive rate
> Sep 07 13:13:28|01529|poll_loop|WARN|wakeup due to [POLLIN] on fd 18 
> (NETLINK_GENERIC<->NETLINK_GENERIC) at ../lib/netlink-socket.c:668 (85% 
> CPU usage)
> Sep 07 13:13:28|01530|poll_loop|WARN|wakeup due to [POLLIN] on fd 21 
> (NETLINK_GENERIC<->NETLINK_GENERIC) at ../lib/netlink-socket.c:668 (85% 
> CPU usage)
> Sep 07 13:13:29|01531|poll_loop|WARN|Dropped 8214 log messages in last 1 
> seconds (most recently, 1 seconds ago) due to excessive rate
> Sep 07 13:13:29|01532|poll_loop|WARN|wakeup due to [POLLIN] on fd 18 
> (NETLINK_GENERIC<->NETLINK_GENERIC) at ../lib/netlink-socket.c:668 (82% 
> CPU usage)
> Sep 07 13:13:29|01533|poll_loop|WARN|wakeup due to [POLLIN] on fd 21 
> (NETLINK_GENERIC<->NETLINK_GENERIC) at ../lib/netlink-socket.c:668 (82% 
> CPU usage)
> Sep 07 13:13:30|01534|poll_loop|WARN|Dropped 5068 log messages in last 1 
> seconds (most recently, 1 seconds ago) due to excessive rate
> Sep 07 13:13:30|01535|poll_loop|WARN|wakeup due to [POLLIN] on fd 18 
> (NETLINK_GENERIC<->NETLINK_GENERIC) at ../lib/netlink-socket.c:668 (82% 
> CPU usage)
> Sep 07 13:13:30|01536|poll_loop|WARN|wakeup due to [POLLIN] on fd 21 
> (NETLINK_GENERIC<->NETLINK_GENERIC) at ../lib/netlink-socket.c:668 (82% 
> CPU usage)
> Sep 07 13:13:31|01537|poll_loop|WARN|Dropped 5008 log messages in last 1 
> seconds (most recently, 1 seconds ago) due to excessive rate
> Sep 07 13:13:31|01538|poll_loop|WARN|wakeup due to [POLLIN] on fd 18 
> (NETLINK_GENERIC<->NETLINK_GENERIC) at ../lib/netlink-socket.c:668 (82% 
> CPU usage)
> Sep 07 13:13:31|01539|poll_loop|WARN|wakeup due to [POLLIN] on fd 21 
> (NETLINK_GENERIC<->NETLINK_GENERIC) at ../lib/netlink-socket.c:668 (82% 
> CPU usage)
> Sep 07 13:13:32|01540|poll_loop|WARN|Dropped 4841 log messages in last 1 
> seconds (most recently, 1 seconds ago) due to excessive rate
> Sep 07 13:13:32|01541|poll_loop|WARN|wakeup due to 40-ms timeout at 
> ../ofproto/ofproto-dpif.c:622 (83% CPU usage)
> Sep 07 13:13:32|01542|poll_loop|WARN|wakeup due to [POLLIN] on fd 18 
> (NETLINK_GENERIC<->NETLINK_GENERIC) at ../lib/netlink-socket.c:668 (83% 
> CPU usage)
> Sep 07 13:13:33|01543|poll_loop|WARN|Dropped 92 log messages in last 1 
> seconds (most recently, 1 seconds ago) due to excessive rate
> Sep 07 13:13:33|01544|poll_loop|WARN|wakeup due to [POLLIN] on fd 18 
> (NETLINK_GENERIC<->NETLINK_GENERIC) at ../lib/netlink-socket.c:668 (83% 
> CPU usage)
> Sep 07 13:13:33|01545|poll_loop|WARN|wakeup due to [POLLIN] on fd 21 
> (NETLINK_GENERIC<->NETLINK_GENERIC) at ../lib/netlink-socket.c:668 (83% 
> CPU usage)
> Sep 07 13:13:34|01546|poll_loop|WARN|Dropped 27 log messages in last 1 
> seconds (most recently, 1 seconds ago) due to excessive rate
> Sep 07 13:13:34|01547|poll_loop|WARN|wakeup due to 53-ms timeout at 
> ../lib/mac-learning.c:294 (83% CPU usage)
> Sep 07 13:13:34|01548|poll_loop|WARN|wakeup due to [POLLIN] on fd 18 
> (NETLINK_GENERIC<->NETLINK_GENERIC) at ../lib/netlink-socket.c:668 (83% 
> CPU usage)
> 
> 
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