Date: Wed, 06 Mar 2024 18:12:20 +0000 From: bugzilla-noreply@freebsd.org To: fs@FreeBSD.org Subject: [Bug 275594] High CPU usage by arc_prune; analysis and fix Message-ID: <bug-275594-3630-kSrNFxQK1r@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-275594-3630@https.bugs.freebsd.org/bugzilla/> References: <bug-275594-3630@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D275594 --- Comment #73 from Anton Saietskii <vsasjason@gmail.com> --- (In reply to Mark Millard from comment #72) TBH, I didn't really get what do you mean by "kind" of hang, but perhaps following will be helpful: (Vanilla releng/13.3 currently.) Machine is running a few daemons with very stable memory footprint (built-in ones, like sshd, ntpd + couple of 3rd party, like net/wifibox, net-p2p/transmission daemon). Nothing related to memory has been tuned, and there's always ~2-3G of free RAM and zero swap usage. Then I start `poudriere bulk`, and as soon as some big distfile (e.g. firef= ox, libreoffice) begins extraction to tmpfs, arc_prune+vnlru start recklessly e= at CPU^W^W^W do their job trying to evict some ARC for me. System becomes slow= and stuttering followed by a full unresponsiveness =E2=80=94 network stops, dis= k activity stops, no reaction on physical console. After several minutes (I guess when distfile finishes extraction), everythi= ng returns to normal like nothing happened with no any log messages. Then poudriere build continues with eventual arc_prune+vnlru running as tmpfs be= ing filled with object files produced by compiler. No a single byte of swap usa= ge observed during this. So, it's like what you described, but for me issue hits faster and harder. Looks like CPU just have no time to execute anything beyond those 2 and possibly some other kernel threads. --=20 You are receiving this mail because: You are the assignee for the bug.=
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