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Bad performance x 2 when using net.bpf.zerocopy_enable=1 on FreeBSD 9.1
From: elof () sentor se
Date: Tue, 19 Feb 2013 16:41:55 +0100 (CET)
I just found something strange: How to reproduce: On a default installed FreeBSD 9.1 (amd64) machine I run the latest snort (compiled from ports). Snort is running fine (as a daemon). I replay a test-pcap with 1 000 000 packets at high speed. 'netstat -B' says: Pid Netif Flags Recv Drop Match Sblen Hblen Command 875 pflog0 p--s--l 0 0 0 0 0 pflogd 1757 mon0 p--s--- 999988 0 999988 0 0 snort So far everything's good. 0 drops. (the 12 missing packets were dropped externally (in a hub)) I stop snort. It terminates just fine within a second or two. Now I run: sysctl net.bpf.zerocopy_enable=1 Then I start snort again. Problem #1: I replay the same 1 000 000 packets at the same speed. 'netstat -B' now show: Pid Netif Flags Recv Drop Match Sblen Hblen Command 875 pflog0 p--s--l 0 0 0 0 0 pflogd 1912 mon0 p--s--- 999978 159417 999978 2096329 2095593 snort Aw! 159417 drops (16%)! This is reproduceable every time. Problem #2: When I now try to terminate the snort process, it won't die. It doesn't even start to syslog that it is shutting down. Nothing happen at all. After a few minutes I give up and kill it with -9. This problem only seem to appear if the monitoring NIC is completely silent (as mine are when I don't replay any test packets). If/when I start replaying some packets again, the snort process that I tried to kill (without -9) now finally terminates. Any ideas what is happening here? /Elof ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_feb _______________________________________________ Snort-devel mailing list Snort-devel () lists sourceforge net https://lists.sourceforge.net/lists/listinfo/snort-devel Archive: http://sourceforge.net/mailarchive/forum.php?forum_name=snort-devel Please visit http://blog.snort.org for the latest news about Snort!
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- Bad performance x 2 when using net.bpf.zerocopy_enable=1 on FreeBSD 9.1 elof (Feb 19)