From owner-svn-src-head@freebsd.org Sat Feb 16 17:08:37 2019 Return-Path: Delivered-To: svn-src-head@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 0537B14EE9A6 for ; Sat, 16 Feb 2019 17:08:37 +0000 (UTC) (envelope-from ian@freebsd.org) Received: from outbound2m.ore.mailhop.org (outbound2m.ore.mailhop.org [54.149.155.156]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 6C76C927F4 for ; Sat, 16 Feb 2019 17:08:36 +0000 (UTC) (envelope-from ian@freebsd.org) ARC-Seal: i=1; a=rsa-sha256; t=1550336852; cv=none; d=outbound.mailhop.org; s=arc-outbound20181012; b=henHUf6VFkdwnmr76G8G50qRCuAHNwRkSw2kaRcYK0yCnQbBH8SDijkiAq1XEYu/7Na+ORHE4Ckwr F9j5ikuLyklgQ8cmAxRrlUYCice8+UR9oJZnAxjG28La/8hmOsnuXpDVV0OCGZmKBwGGedtjKbd9WT x9p5kU+Eep6Z2X2/Jiqh/V9PipeK34TeMx7wzyHi/OSs8mrJ7Yj0R9jY+4L2CcIXqGF4ecSFcTzl1N iuhugetEbKy8OEjW35P8/SUCm6kRlYuWUMxqxr+CtEfiPbrh2gKxNhy6WQVfuHEoH9cuPl7Hq1MFEY ZXxfXut7pbOGKlRdSgK6MXS1+Fi1m1Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=outbound.mailhop.org; s=arc-outbound20181012; h=content-transfer-encoding:mime-version:content-type:references:in-reply-to: date:cc:to:from:subject:message-id:dkim-signature:from; bh=YGyRdnV7WGIpWjQsL1LIzz+eccunxi3pgOy7dO5VpB0=; b=OVwK+VDR3z+1RWkO0O426kuB6SPoScySQbkN1shGdF59YKtHJiR3I7lr5t6+cxwlRanBiWM8dYbFN /5XIaHblJO4TbFCPvvO0LnPEtEE31CXfNyeqzzNcUvhcdNWDCWbWO2sef/k4cJ1KbfjmGwNyL5EgFx YiInA+RKLKeJ2OhTpR92T7ag6oTnn8CzkQntksBZGyZBBF8Q/tcLNwxASuj6/dqCyk1uWpjh0VmQIn xsZ7l500XvJfWIO4FDtf5s0O5ayEJCdPUqQ1mxbGlVN8qVMRJXlo+dweu4320Xd7n8PVkff3TVGdK+ 2SMgQcMoi9zMQdcJ46QDFdvG0ZHhrmA== ARC-Authentication-Results: i=1; outbound4.ore.mailhop.org; spf=softfail smtp.mailfrom=freebsd.org smtp.remote-ip=67.177.211.60; dmarc=none header.from=freebsd.org; arc=none header.oldest-pass=0; DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=outbound.mailhop.org; s=dkim-high; h=content-transfer-encoding:mime-version:content-type:references:in-reply-to: date:cc:to:from:subject:message-id:from; bh=YGyRdnV7WGIpWjQsL1LIzz+eccunxi3pgOy7dO5VpB0=; b=uXracKMj92CKtK0ddv27+US78a3mHEH22S+A13Yk+2SEj/sNhGXZ5xzFS51V6dRlNi0N02fiVMgX2 W+FBcDAG9xnDir2T+QIdEo05jP2vnliXe9pGq6s1z7yFNeZ0AG9Cq2EQ517QaPj7xYdvePwRm4Nmo7 dfXvFve/JNSAgMtSQSNWQ9YQAYFiPEJMBXaLHFSVXCcTrGfDzK3D9KJB61lvWD7/pg3xb9s82Glxvd Yz2AQVWj1OegiQt4U8HR29J9fY5ARhIhgIf/x7+umLYRmidZRBNyLpM3YVcg8aoUrfJ9kr1g88g8eN ruX8TdeMnYvnSjJ/6Wn4491BH+Jo86Q== X-MHO-RoutePath: aGlwcGll X-MHO-User: 57cb0605-320d-11e9-befd-af03bedce89f X-Report-Abuse-To: https://support.duocircle.com/support/solutions/articles/5000540958-duocircle-standard-smtp-abuse-information X-Originating-IP: 67.177.211.60 X-Mail-Handler: DuoCircle Outbound SMTP Received: from ilsoft.org (unknown [67.177.211.60]) by outbound4.ore.mailhop.org (Halon) with ESMTPSA id 57cb0605-320d-11e9-befd-af03bedce89f; Sat, 16 Feb 2019 17:07:31 +0000 (UTC) Received: from rev (rev [172.22.42.240]) by ilsoft.org (8.15.2/8.15.2) with ESMTP id x1GH8WrC072882; Sat, 16 Feb 2019 10:08:32 -0700 (MST) (envelope-from ian@freebsd.org) Message-ID: <259b30371291398891b48c38fc8231e7422f47e4.camel@freebsd.org> Subject: Re: svn commit: r344188 - in head: lib/libc/sys sys/vm From: Ian Lepore To: Bruce Evans , Gleb Smirnoff Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Date: Sat, 16 Feb 2019 10:08:32 -0700 In-Reply-To: <20190217011341.S833@besplex.bde.org> References: <201902152336.x1FNaNUo039321@repo.freebsd.org> <20190217011341.S833@besplex.bde.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5 FreeBSD GNOME Team Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 6C76C927F4 X-Spamd-Bar: ------ Authentication-Results: mx1.freebsd.org X-Spamd-Result: default: False [-6.98 / 15.00]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; NEURAL_HAM_SHORT(-0.98)[-0.983,0]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; REPLY(-4.00)[] X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 16 Feb 2019 17:08:37 -0000 On Sun, 2019-02-17 at 02:58 +1100, Bruce Evans wrote: > Slowness is relative. In FreeBSD-1, floppy disk devices were still in > use and were especially slow. Now hard disks are slow relative to fast > SSDs. But the number of buffers was unchanged. It is still essentially > unchanged except for vn pager pbufs. The hard disks can complete 128 > i/o's for a full queue much faster than a floppy disk, so the relative > slowness might be similar, but now there are more subsystems and some > systems have many more disks. The modern replacement for a floppy disk in this regard is an sdcard. When doing large numbers of random writes, such as untarring a snapshot of rootfs to a ufs filesystem on sdcard, gstat will show ms/w values anywhere from 30,000 to 90,000 depending on the card. It stays that way throughout the operation, and IO to all other disks on the system essentially comes to a standstill. This is true whether the card is in a native sdhci controller or a usb-attached multiformat reader/burner. -- Ian