From owner-freebsd-hackers@freebsd.org Sun Dec 2 07:43:49 2018 Return-Path: Delivered-To: freebsd-hackers@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 91C581313E48 for ; Sun, 2 Dec 2018 07:43:49 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: from mail-qt1-x832.google.com (mail-qt1-x832.google.com [IPv6:2607:f8b0:4864:20::832]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id CF82F88B6E for ; Sun, 2 Dec 2018 07:43:48 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: by mail-qt1-x832.google.com with SMTP id i7so10507704qtj.10 for ; Sat, 01 Dec 2018 23:43:48 -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=CxxDX5/01e5FU+jGbBSZ+CMpM59eqwJb7fqNXp80joU=; b=JQ9mBhypaI8fzNKSo9cqVzrcdrPfSfT1/yZkTE14sz2jmB75QG1I+lcGo9Xi/5XOjq dzjVT3WIsnqI9W65nva1N6U19HuQRin+J45+3S5ByZ9s/mUVhd5XjgO1EDtQK1EzX33d bOR6O31jKOZPlJwx1gBQohnhpwMU+pVKK3kwC+c8NC4emg7p8LoQLXpq9KdGWnJd5vtZ tfZH/L4wOnqplcDGONYp3KTmSStiBDl765gZLMLqzHpkkix7OEBva0/QXFmbyL0O/D8g aF3n+d+wjIxLCXrL/6HHNmz1HY9z2HRWY8vaCkPpXKgfKynlvy/mMnsr3f1pEk603+0M +lhQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=CxxDX5/01e5FU+jGbBSZ+CMpM59eqwJb7fqNXp80joU=; b=r6J84BtnOgpAnTh6RHJZ0bX/+nLmwBnwj5VX+soVtfyE/RjrVM6PKs53FI/zLy2TGn Ft/pXc4kYxCQ1FHdem4UgubKiq+1CMJ5gPPc+RLwifsxrnUa2WBBUWLO+r5JV2Ce/RT2 zOjEGNbFfzXdv/H7WKKGBL4HSAA24XtdMzUoT+sp7oD0PUFv3w3ocLwKkjcdzBtsyY/F 2TpCOF+yYI8FzOdmorKS5n0txIz8MXJf2Xtxgefw1/RZydQ1i5IwZeDPPLZXjluLb8iF K3BYl5eLFzcGDentJeqfssg2Y3QTIKgHt5ojbPCo9AS0HQpufyh3BgteNSm+sx16KDOi ABMg== X-Gm-Message-State: AA+aEWanrjzp6Pc+a/VuAVUKa/b1cBjpgUQc3UpEgxO2EQeCJgo9jESR 0U79vghNKlfetYKxXVSscm0fziVPNchgxbjJ5Vw4dA== X-Google-Smtp-Source: AFSGD/X5bcfoHvZiHGGeQtJP0Q+G8YeGnufcgIGAXsY/bESnJjrGdpTDGXkTS9ex7iKTecfNBxV2+OmWFkAdlExTn5A= X-Received: by 2002:aed:3881:: with SMTP id k1mr10906855qte.345.1543736623171; Sat, 01 Dec 2018 23:43:43 -0800 (PST) MIME-Version: 1.0 References: <7e69211c-6ffb-6155-b17a-a845c0b3586d@grosbein.net> <20181201.093153.893601099798031027.ish@amail.plala.or.jp> <1c7139bd-258c-e7d2-2572-052da3803b3b@freebsd.org> <20181201.202332.546134930481017424.ish@amail.plala.or.jp> <12404.1543699424@critter.freebsd.dk> <20181201222424.0ae8abfd@gumby.homeunix.com> <1177.1543704042@critter.freebsd.dk> <60912.1543734235@critter.freebsd.dk> In-Reply-To: <60912.1543734235@critter.freebsd.dk> From: Warner Losh Date: Sun, 2 Dec 2018 00:43:31 -0700 Message-ID: Subject: Re: How to use trim command ?,Re: How to use trim command ? To: Poul-Henning Kamp Cc: RW , "freebsd-hackers@freebsd.org" X-Rspamd-Queue-Id: CF82F88B6E X-Spamd-Result: default: False [-3.90 / 15.00]; ARC_NA(0.00)[]; TO_DN_EQ_ADDR_SOME(0.00)[]; R_DKIM_ALLOW(-0.20)[bsdimp-com.20150623.gappssmtp.com]; NEURAL_HAM_MEDIUM(-1.00)[-0.999,0]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[3]; TO_DN_SOME(0.00)[]; NEURAL_HAM_LONG(-1.00)[-0.998,0]; MIME_GOOD(-0.10)[multipart/alternative,text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-hackers@freebsd.org]; DMARC_NA(0.00)[bsdimp.com]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_SOME(0.00)[]; MX_GOOD(-0.01)[cached: ALT1.aspmx.l.google.com]; DKIM_TRACE(0.00)[bsdimp-com.20150623.gappssmtp.com:+]; RCVD_IN_DNSWL_NONE(0.00)[2.3.8.0.0.0.0.0.0.0.0.0.0.0.0.0.0.2.0.0.4.6.8.4.0.b.8.f.7.0.6.2.list.dnswl.org : 127.0.5.0]; NEURAL_HAM_SHORT(-0.97)[-0.971,0]; R_SPF_NA(0.00)[]; FORGED_SENDER(0.30)[imp@bsdimp.com,wlosh@bsdimp.com]; SUBJECT_ENDS_QUESTION(1.00)[]; RCVD_TLS_LAST(0.00)[]; ASN(0.00)[asn:15169, ipnet:2607:f8b0::/32, country:US]; FROM_NEQ_ENVFROM(0.00)[imp@bsdimp.com,wlosh@bsdimp.com]; IP_SCORE(-1.92)[ip: (-6.52), ipnet: 2607:f8b0::/32(-1.68), asn: 15169(-1.30), country: US(-0.09)]; FREEMAIL_CC(0.00)[googlemail.com] X-Rspamd-Server: mx1.freebsd.org 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 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 02 Dec 2018 07:43:49 -0000 On Sun, Dec 2, 2018 at 12:03 AM Poul-Henning Kamp wrote: > -------- > In message < > CANCZdfrb0gWAhSUAVvs0pBjezWgh3c_kHjriknC02KZF+MVE9A@mail.gmail.com>, > Warner Losh writes: > > >Erase has become super expensive with QLC nand. And many SSDs are trying > to > >use simpler, smaller data structures to implement its LUTs. > > They may not have a choice, there are patent-issues in this space. > > Still, I would avoid any SSD which has issues in this space for normal > filesystem operations. > Good advice, if you can afford the more expensive NAND... Cost reduction efforts have lead me to try to make such NAND suck less. Warner