Date: Thu, 9 Jan 2020 10:57:58 +0100 (CET) From: Wojciech Puchar <wojtek@puchar.net> To: Conrad Meyer <cem@freebsd.org> Cc: Konstantin Belousov <kostikbel@gmail.com>, Hans Petter Selasky <hps@selasky.org>, Rick Macklem <rmacklem@uoguelph.ca>, Wojciech Puchar <wojtek@puchar.net>, "freebsd-hackers@freebsd.org" <freebsd-hackers@freebsd.org> Subject: Re: maximum MAXBSIZE Message-ID: <alpine.BSF.2.20.2001091057420.96836@puchar.net> In-Reply-To: <CAG6CVpUrGyov12nQSKhofCPw5fAiXgDGChxf3-aFu1fKpirJTQ@mail.gmail.com> References: <alpine.BSF.2.20.2001072210410.21107@puchar.net> <d79078c4-f1cb-93b9-ee6e-f689936c1e01@selasky.org> <YQBPR0101MB1427EEDE94AA6E34B49C3C09DD3F0@YQBPR0101MB1427.CANPRD01.PROD.OUTLOOK.COM> <20200108105136.0d54ebce@ernst.home> <alpine.BSF.2.20.2001081452360.44533@puchar.net> <20200108141810.GX23031@kib.kiev.ua> <CAG6CVpUrGyov12nQSKhofCPw5fAiXgDGChxf3-aFu1fKpirJTQ@mail.gmail.com>
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2MB MAXPHYS was what i have set for over 3 years without problems. On Wed, 8 Jan 2020, Conrad Meyer wrote: > Bufs are dynamically allocated from uma now, and perhaps a middle ground BSIZE is worth considering? Would 1MB and 2kB bufs (1kB > 32-bit) be awful? > > Cheers, > Conrad > > On Wed, Jan 8, 2020 at 06:18 Konstantin Belousov <kostikbel@gmail.com> wrote: > On Wed, Jan 08, 2020 at 02:52:57PM +0100, Wojciech Puchar wrote: > > sorry i made a mistake - i change MAXPHYS not MAXBSIZE. > > > > 16MB works for now without problems > MAXPHYS 16MB means that sizeof(struct buf) is around 32K (16K on 32bit). > > > > > On Wed, 8 Jan 2020, Gary Jennejohn wrote: > > > > > On Tue, 7 Jan 2020 22:47:54 +0000 > > > Rick Macklem <rmacklem@uoguelph.ca> wrote: > > > > > > > Hans Petter Selasky wrote: > > > > > On 2020-01-07 22:12, Wojciech Puchar wrote: > > > > > > default MAXBSIZE is 128kB. badly low for todays magnetic disks. > > > > > > > > > > > > i have it set to 2MB on all computers that have magnetic disks. Great > > > > > > improvement with large files. especially when more than one are > > > > > > read/wrote in parallel. And no problems experienced > > > > > > > > > > > > But for optimal performance MAXBSIZE should be transfered in few times > > > > > > longer than average seek time. todays disk do 200-250MB/s so 2MB is > > > > > > transfered below 10ms. > > > > > > > > > > > > 8-16MB seems like good choice. is there any reason not to set it that high? > > > > > > > > > > Old disk may not support it, especially USB 1.0/2.0 disks. > > > > I also thought it was limited to MAXPHYS, but maybe I'm only thinking of the NFS > > > > specific case? > > > > > > > > > > There's a comment in param.h that it should not exceed MAXPHYS to be > > > on the safe side. How old that comment is I can't say and that may > > > not be the case today. > > > > > > MAXBSIZE is only 64KiB in my param.h. > > > > > > I have to agree with HPS. There are many old bridge-chips still in > > > use and problems with a large MAXBSIZE might occur. It's certainly > > > not uncommon to see capacity limitations - I have a docking station > > > which can't see more than 3TB. > > > > > > -- > > > Gary Jennejohn > > > > > > > > _______________________________________________ > > freebsd-hackers@freebsd.org mailing list > > https://lists.freebsd.org/mailman/listinfo/freebsd-hackers > > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org" > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org" > > > From owner-freebsd-hackers@freebsd.org Thu Jan 9 14:14:36 2020 Return-Path: <owner-freebsd-hackers@freebsd.org> Delivered-To: freebsd-hackers@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 42C941EF6DF for <freebsd-hackers@mailman.nyi.freebsd.org>; Thu, 9 Jan 2020 14:14:36 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: from mail-qk1-x72e.google.com (mail-qk1-x72e.google.com [IPv6:2607:f8b0:4864:20::72e]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1O1" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 47tp5l2bB0z4BJv for <freebsd-hackers@freebsd.org>; Thu, 9 Jan 2020 14:14:35 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: by mail-qk1-x72e.google.com with SMTP id k6so6060214qki.5 for <freebsd-hackers@freebsd.org>; Thu, 09 Jan 2020 06:14:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bsdimp-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=N/YAohDje5wqg0z4wWLXOqqy27XUFukLKDn7iEXkbiQ=; b=rLr0GeSuaeMsCG4DT4+GLhnWqfYrkySkhuC9GWN7bcl3rcsERNz3AfLDeXfAqaqRuh 3UgziXvG+RcYg5LWEBJYagew5CgR3t9t8gJVjU6mhhqklSjSdWJ4hm1obW/iI2/OHJQf CmSyqKcpQK8Xb40CIDsy0/hMGBOjEpDWhcPQEQiyxQomeqqPFg6mPoO6SZLIVOjr4cg4 0CeGAiGiuQarb7P+umHAdLqq2m98Lj+c3DtsazAHBDUm78qB/fPie6TBIPINHi8ZqIvM Q48Aecl2c8loHT2qF6F6sDHO3YuI+FLPScv3BGtPvVDizlv3WPweJmafB9AbByvxlxPs DbBQ== X-Google-DKIM-Signature: v=1; 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IP_SCORE(-2.65)[ip: (-9.21), ipnet: 2607:f8b0::/32(-2.12), asn: 15169(-1.85), country: US(-0.05)]; ASN(0.00)[asn:15169, ipnet:2607:f8b0::/32, country:US]; FROM_NEQ_ENVFROM(0.00)[imp@bsdimp.com,wlosh@bsdimp.com]; RCVD_TLS_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2] Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.29 X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Technical Discussions relating to FreeBSD <freebsd-hackers.freebsd.org> List-Unsubscribe: <https://lists.freebsd.org/mailman/options/freebsd-hackers>, <mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe> List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers/>; List-Post: <mailto:freebsd-hackers@freebsd.org> List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help> List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, <mailto:freebsd-hackers-request@freebsd.org?subject=subscribe> X-List-Received-Date: Thu, 09 Jan 2020 14:14:36 -0000 Netflix runs our entire network at MAXPHYS=8MB since we're doing huge reads off HDD. Warner On Thu, Jan 9, 2020 at 2:58 AM Wojciech Puchar <wojtek@puchar.net> wrote: > 2MB MAXPHYS was what i have set for over 3 years without problems. > > On Wed, 8 Jan 2020, Conrad Meyer wrote: > > > Bufs are dynamically allocated from uma now, and perhaps a middle ground > BSIZE is worth considering? Would 1MB and 2kB bufs (1kB > > 32-bit) be awful? > > > > Cheers, > > Conrad > > > > On Wed, Jan 8, 2020 at 06:18 Konstantin Belousov <kostikbel@gmail.com> > wrote: > > On Wed, Jan 08, 2020 at 02:52:57PM +0100, Wojciech Puchar wrote: > > > sorry i made a mistake - i change MAXPHYS not MAXBSIZE. > > > > > > 16MB works for now without problems > > MAXPHYS 16MB means that sizeof(struct buf) is around 32K (16K on > 32bit). > > > > > > > > On Wed, 8 Jan 2020, Gary Jennejohn wrote: > > > > > > > On Tue, 7 Jan 2020 22:47:54 +0000 > > > > Rick Macklem <rmacklem@uoguelph.ca> wrote: > > > > > > > > > Hans Petter Selasky wrote: > > > > > > On 2020-01-07 22:12, Wojciech Puchar wrote: > > > > > > > default MAXBSIZE is 128kB. badly low for todays magnetic > disks. > > > > > > > > > > > > > > i have it set to 2MB on all computers that have magnetic > disks. Great > > > > > > > improvement with large files. especially when more than > one are > > > > > > > read/wrote in parallel. And no problems experienced > > > > > > > > > > > > > > But for optimal performance MAXBSIZE should be > transfered in few times > > > > > > > longer than average seek time. todays disk do > 200-250MB/s so 2MB is > > > > > > > transfered below 10ms. > > > > > > > > > > > > > > 8-16MB seems like good choice. is there any reason not > to set it that high? > > > > > > > > > > > > Old disk may not support it, especially USB 1.0/2.0 disks. > > > > > I also thought it was limited to MAXPHYS, but maybe I'm only > thinking of the NFS > > > > > specific case? > > > > > > > > > > > > > There's a comment in param.h that it should not exceed MAXPHYS > to be > > > > on the safe side. How old that comment is I can't say and > that may > > > > not be the case today. > > > > > > > > MAXBSIZE is only 64KiB in my param.h. > > > > > > > > I have to agree with HPS. There are many old bridge-chips > still in > > > > use and problems with a large MAXBSIZE might occur. It's > certainly > > > > not uncommon to see capacity limitations - I have a docking > station > > > > which can't see more than 3TB. > > > > > > > > -- > > > > Gary Jennejohn > > > > > > > > > > > _______________________________________________ > > > freebsd-hackers@freebsd.org mailing list > > > https://lists.freebsd.org/mailman/listinfo/freebsd-hackers > > > To unsubscribe, send any mail to " > freebsd-hackers-unsubscribe@freebsd.org" > > _______________________________________________ > > freebsd-hackers@freebsd.org mailing list > > https://lists.freebsd.org/mailman/listinfo/freebsd-hackers > > To unsubscribe, send any mail to " > freebsd-hackers-unsubscribe@freebsd.org" > > > > > > > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org" >
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