Date: Sat, 29 May 2021 09:52:34 +0000 From: bugzilla-noreply@freebsd.org To: net@FreeBSD.org Subject: [Bug 256217] [tcp] High system load because of interrupts with RACK Message-ID: <bug-256217-7501-pXGVi00VtT@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-256217-7501@https.bugs.freebsd.org/bugzilla/> References: <bug-256217-7501@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D256217 --- Comment #7 from Christos Chatzaras <chris@cretaforce.gr> --- I was able to reproduce the issue with a "test" server && 10 VPS running Li= nux. On each VPS I run wrk (benchmarking tool): wrk -c 1000 -d 3600s http://url This creates 10000 concurrent connections to "test" server. Also in my nginx.conf I replace "keepalive_timeout 60;" with "keepalive_tim= eout 0;" so connections are not reused which helps to show more interrupts faste= r. Then I kill all "wrk" and after 1 minute: sockstat -sSPtcp | grep rack | wc -l 7421 At that moment "top" shows 20% interrupts and "netstat 1" show 1-10 packets= / sec which I believe is my ssh session, so no activity. Also at that moment = tcp "rack" states were FIN_WAIT_1 and CLOSING. After few minutes most "rack" connections close and "top" shows ~ 0.7% interrupts. At that moment I had 4 stuck connections in LAST_ACK state whic= h I drop using "tcpdrop -s LAST_ACK" and finally "top" shows ~ 0.0% interrupts. If it helps I can give root access to the "test" server. --=20 You are receiving this mail because: You are the assignee for the bug.=
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