[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-users] XEN 4.3.1 network performance issue
> On Tue, Dec 24, 2013 at 05:06:37PM +0200, NiX wrote: >> Hi. I am running a XEN VM in PV mode. This VM has four cores enabled. VM >> network config is as follows: >> >> vif = ["ip=127.0.0.1,mac=XX:XX:XX:XX:XX:XX,bridge=br0,rate=100Mb/s"] >> >> Dom0 is dual XEON X5450 with 16GB of RAM. >> >> I can barely zmap at 10mbps ~ 12k packets/second on this VM >> > > My google-fu tells me that zmap sends out gigantic amount of TCP SYN > packets in its default configuration. It is possible the ring size > between frontend and backend is the bottleneck. Data copying from > frontend to backend might also be a problem. > > You can probably patch your Dom0 and DomU kernel with multi-page ring > support to see if it makes it better. > > Wei. > I was not able neither to exceed 10k packets/second with a lightweight equivalent software and netback/0 fully utilized one 3GHz core. Of course I had tweaked both host/vm network because the default limits somewhat cannot properly handle 10k or more packets/second due to the default 1k open files limit and so forth Well you know, basic users can manage with 1k packets and/or connections second but I am not a basic user ;) Is there any handy link on how to use multi-page ring feature. I am going to test that. I think this is something to test/compare with another virtualization software's as well. I had tweaks as follows on both host/guest: cat /etc/security/limits.conf root hard nofile 102400 root soft nofile 102400 ulimit -a open files (-n) 102400 cat /etc/sysctl.conf net.ipv4.tcp_moderate_rcvbuf = 0 net.ipv4.tcp_window_scaling = 1 net.ipv4.tcp_timestamps = 0 net.ipv4.tcp_sack = 1 net.ipv4.tcp_fack = 1 net.ipv4.tcp_dsack = 1 net.ipv4.tcp_app_win = 8 net.ipv4.tcp_adv_win_scale = 1 net.ipv4.tcp_frto = 1 net.ipv4.tcp_no_metrics_save = 1 net.ipv4.ip_no_pmtu_disc = 1 net.core.rmem_max = 8388608 net.core.wmem_max = 8388608 net.core.rmem_default = 4129093 net.core.wmem_default = 4129093 net.ipv4.tcp_rmem = 4129093 6566366 8388608 net.ipv4.tcp_wmem = 4129093 6566366 8388608 net.ipv4.tcp_mem = 8388608 8388608 8388608 net.core.netdev_max_backlog = 3000 net.core.optmem_max = 200000 vm.min_free_kbytes = 16384 net.ipv4.tcp_low_latency = 0 net.ipv4.route.flush = 1 net.ipv4.netfilter.ip_conntrack_max = 4194304 # Force gc to clean-up quickly net.ipv4.neigh.default.gc_interval = 3600 # Set ARP cache entry timeout net.ipv4.neigh.default.gc_stale_time = 3600 # Setup DNS threshold for arp net.ipv4.neigh.default.gc_thresh3 = 4096 net.ipv4.neigh.default.gc_thresh2 = 2048 net.ipv4.neigh.default.gc_thresh1 = 1024 _______________________________________________ Xen-users mailing list Xen-users@xxxxxxxxxxxxx http://lists.xen.org/xen-users
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