Date: Mon, 11 Jul 2016 12:37:21 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 211003] net.inet.tcp.delayed_ack=0 and local TCP traffic Message-ID: <bug-211003-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D211003 Bug ID: 211003 Summary: net.inet.tcp.delayed_ack=3D0 and local TCP traffic Product: Base System Version: 10.2-STABLE Hardware: Any OS: Any Status: New Severity: Affects Many People Priority: --- Component: kern Assignee: freebsd-bugs@FreeBSD.org Reporter: moko@moko.ru We have many FreeBSD installations and some of them historically have the following settings in /etc/sysctl.conf: net.inet.tcp.delayed_ack=3D0 net.inet.tcp.recvspace=3D8192 net.inet.tcp.sendspace=3D150000 After upgrading to 10.2 we've run into an issue - local http requests were delaying after every 8kb of data for 5 seconds. lynx --mime_header "http://<server ip>/any file around 200kb" first we get 4Kb (incuding headers) 5 seconds delay (exact value, not an approximate) next 8Kb 5 seconds delay next 8Kb ... and so on. Everything is fine if the file is requested remotely, only local requests h= ave such delays. Nginx or apache - both have the delays. We also where able to reproduce the delays in virtualized environment. There are no issues with t= his sysctl settings in FreeBSD 8.X and FreeBSD 9.X. Setting net.inet.tcp.sendspace=3D4096 "hides" the issue. Increasing net.inet.tcp.recvspace to more then 32664 also "hides" the issue. Restoring net.inet.tcp.delayed_ack to default 1 also "hides" the issue but there are still some performance issues if net.inet.tcp.recvspace is low: >sysctl net.inet.tcp.recvspace=3D8192 >time lynx --mime_header "local file around 200 kb" > /dev/null 0.009u 0.000s 0:01.41 0.0% 0+0k 0+0io 0pf+0w >sysctl net.inet.tcp.recvspace=3D32768 >time lynx --mime_header "local file around 200 kb" > /dev/null 0.009u 0.000s 0:00.01 0.0% 0+0k 0+0io 0pf+0w --=20 You are receiving this mail because: You are the assignee for the bug.=
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