From owner-freebsd-bugs@freebsd.org Sun Aug 26 05:09:28 2018 Return-Path: Delivered-To: freebsd-bugs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id E7DAE10A22FE for ; Sun, 26 Aug 2018 05:09:27 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mailman.ysv.freebsd.org (mailman.ysv.freebsd.org [IPv6:2001:1900:2254:206a::50:5]) by mx1.freebsd.org (Postfix) with ESMTP id 857F87126D for ; Sun, 26 Aug 2018 05:09:27 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.ysv.freebsd.org (Postfix) id 49F0A10A22FD; Sun, 26 Aug 2018 05:09:27 +0000 (UTC) Delivered-To: bugs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 2840010A22FC for ; Sun, 26 Aug 2018 05:09:27 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.ysv.freebsd.org (mxrelay.ysv.freebsd.org [IPv6:2001:1900:2254:206a::19:3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mxrelay.ysv.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id BC9EC7126C for ; Sun, 26 Aug 2018 05:09:26 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2001:1900:2254:206a::16:76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.ysv.freebsd.org (Postfix) with ESMTPS id F1D5C23B31 for ; Sun, 26 Aug 2018 05:09:25 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id w7Q59Pt8046983 for ; Sun, 26 Aug 2018 05:09:25 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id w7Q59Pm5046982 for bugs@FreeBSD.org; Sun, 26 Aug 2018 05:09:25 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 230903] remount root readonly slow on Alix Date: Sun, 26 Aug 2018 05:09:25 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: 11.2-STABLE X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: sthalik@tehran.lain.pl X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: bugs@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.27 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 26 Aug 2018 05:09:28 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D230903 Bug ID: 230903 Summary: remount root readonly slow on Alix Product: Base System Version: 11.2-STABLE Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: sthalik@tehran.lain.pl Hey, On this Alix machine, mounting root readonly after mounting it read-write is slow, as in: % mount -w / % time mount -r / # 15-20 seconds A workaround is to mount the partition async in which case the remount is almost instant. My typical workflow is to mount read-write, break something, then remount read-only for the sake of fsck(8). The original Alix series use a Compact Flash -> ATA controller. I've observ= ed this behavior with multiple CF cards. Typical WCHAN is `biowr', `wdrain' or both. This behavior persists since at least FreeBSD 10 series. Note, the CF storage isn't that slow, see: cat /usr/lib/* > /dev/null 0.10s user 1.21s system 46% cpu 2.821 total cat /usr/bin/* > /dev/null 0.12s user 3.09s system 67% cpu 4.756 total There are some nasty things in KERNCONF, only to reduce logspam and save ti= me otherwise spent probing for nonexistent controllers. The Alix series have n= one of these controllers: -->-- include GENERIC [trivia] nooptions SMP nooptions APIC_IO nodevice acpi nodevice xenpci # fix build nooptions XENHVM # idem nodevice hyperv # idem --<-- I can attach various config files (sysctl.conf, rc.conf, dmesg.boot, fstab, KERNCONF) if necessary but they look sane other than the aforementioned KERNCONF. cheers, sh --=20 You are receiving this mail because: You are the assignee for the bug.=