From owner-dev-commits-src-all@freebsd.org Tue Feb 9 03:20:24 2021 Return-Path: Delivered-To: dev-commits-src-all@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 293A752CE7B for ; Tue, 9 Feb 2021 03:20:24 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: from mail-qt1-x82f.google.com (mail-qt1-x82f.google.com [IPv6:2607:f8b0:4864:20::82f]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 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 4DZSnh0Qv1z3rNn for ; Tue, 9 Feb 2021 03:20:23 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: by mail-qt1-x82f.google.com with SMTP id v3so12039604qtw.4 for ; Mon, 08 Feb 2021 19:20:23 -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=k5uYUfh05w0MoiaqOWuTbf0lu8lKPwDKSD0WCHOv1J8=; b=OsQCU/Z/BtpiJP2zr+ZHx/xvy72lbRUVzvFNjjfptqp2WkCjttFZC8hitu/spYRbTP lZOJSQHGecKU4U2yhr8f1/id2T/ZOsuc8moY/bs7oh3tORiR9T5gh9n2QasXqDPzTnyp 8eqG3CUAM9+FlIRIv1tDtPRS+vp5ZkTT7jH2DsmZ1s2DwaNJAfmj1jgLbqAmJij0PRtf /5B5VKeirrPRvTY2iJFeEWEstRKFw+bT/3+ARAahH7+iug9V7gxu/BxFpZwiYL9jAtaM r/K3lIHuaX6kQbPvAkkMyWKnoH6aAUqgk/q/IFYiGB+kJm7slnD+PWtFREJyCCYs2XBL rX9Q== 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=k5uYUfh05w0MoiaqOWuTbf0lu8lKPwDKSD0WCHOv1J8=; b=GqiTuLWVjaIEspDo+qcfISHhPPF8eIObUtj7ENUD5sdO1cfDdMpdEBKk1tF9884hDu Vw2XDHhk6snoYlq4QMc1HPQ6pD8SG2H6KX/aYNqopag4cmy7B8+FCZEdndclAIqLQGT/ lvkPS86B9PB5uQq7Sc4U3OxCsv7yM/MwhhRIAavWXukYzBgYagBUYENCCYTieTPr2UDV FsSag+n5ZiHGJFAaoLjVf6Tb6yzB4MDy2lWRRtRJhg3GIRwbyC4rUZeqGolicxBdUn6a 2TpRIqiwFv7Ze/K9uyWx+21pbniz6BuGBxjXU+SyfHUrNaSZyFUwD/x5vurJa7jv4fy2 RADA== X-Gm-Message-State: AOAM532HIja6nz7gLCIw/Y0knZMAFIGd+lduqPL6izXl3kOBBE22IHhS kW4n3lOENQ6IwkP7HJzlhZlo3dZuuUwk3pdVjd2xixHjR4nq7g== X-Google-Smtp-Source: ABdhPJz2+zz4blMWkUBzooQnlXsBNyIFXScysukKh3sy8TfEtH8Z80gIzox3Ak0iEo3+wgrO+1Wau/k8uSFXJiexc1U= X-Received: by 2002:aed:2de2:: with SMTP id i89mr18252790qtd.73.1612840822629; Mon, 08 Feb 2021 19:20:22 -0800 (PST) MIME-Version: 1.0 References: <202102081915.118JFXkJ067892@gitrepo.freebsd.org> <3E64387A-42DD-4470-8893-5B774F19754E@freebsd.org> <8E61EA5C-39D1-49CC-8319-06E9192FF735@freebsd.org> In-Reply-To: From: Warner Losh Date: Mon, 8 Feb 2021 20:20:11 -0700 Message-ID: Subject: Re: git: af366d353b84 - main - amd64: implement strlen in assembly To: Kevin Bowling Cc: Jessica Clarke , Mateusz Guzik , "dev-commits-src-all@freebsd.org" , "dev-commits-src-main@freebsd.org" , "src-committers@freebsd.org" X-Rspamd-Queue-Id: 4DZSnh0Qv1z3rNn X-Spamd-Bar: ---- Authentication-Results: mx1.freebsd.org; none X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[] Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.34 X-BeenThere: dev-commits-src-all@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commit messages for all branches of the src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 09 Feb 2021 03:20:24 -0000 Kevin, I'm sure that you think you are being reasonable. But you sure are coming off as attacking Jessica and I for a polite request to adhere to documented project norms. It's not unreasonable to make a request. You are proposing a crazy and unreasonable standard by attacking Jessica and I with the "would you have reviewed it?" line. I personally look at every single src review. I don't comment on them all. I don't know if I can until I take a look, but I at least read the summaries. It's cool that mjg has gone ahead and rewritten strlen. However, that's not a blank check to ignore project norms, nor for others to attack those that suggest it. The code is only about 50 lines of assembler, well within the range of code that often gets a good review. Suggesting that it would have benefitted from a review is not picking on mjg. Anyway, this is the last thing I'll post here... These threads get way out of hand, so if you want to post a rebuttal, I'll give you the last word. Warner On Mon, Feb 8, 2021 at 5:18 PM Kevin Bowling wrote: > I understand your position and Warner=E2=80=99s from the documentation. = The > problem which is not described is that frustration is asymptotically high= er > in the other direction without volunteering to do work. As another examp= le > I could reply and ask for unit tests for any change (tests are obviously > helpful too) but unless I am willing to help it is just a suggestion and > should not be sent as a command. If you are willing to do such reviews > timely, or have command of someone who will, I will coordinate with mjg a= nd > person. Otherwise it=E2=80=99s volunteering other people=E2=80=99s time = and reduces the > willpower to fix these performance areas. > > The head model supports occasional break and revert. I think this is > important given the resources FreeBSD has available, since a lot of the > less glamorous work is unpaid and underpaid. > > Picking on mjg for this is suspicious given how frequently breakage > happens by anyone right now juxtaposed to his track record of improvement= s > and quickness to address issues or revert where issue arose. > > Regards, > Kevin > > On Mon, Feb 8, 2021 at 4:19 PM Jessica Clarke wrote: > >> > On 8 Feb 2021, at 23:13, Kevin Bowling >> wrote: >> > >> > FreeBSD does not require pre-commit approval unless called out >> > specifically. Are you volunteering to review the changes, and if so >> > where is your guidance? These messages are otherwise unhelpful. >> >> It is not a hard requirement, but it is strongly encouraged. Section 7 >> of the committer's guide says: >> >> =E2=80=A2 All non-trivial changes should be reviewed before they= are >> committed to the repository. >> >> This was a non-trivial change. I was particularly frustrated to see >> this commit go in without review having previously called out mjg@ for >> not getting any reviews for his (now reverted) previous strlen change. >> >> Jess >> >> > On Mon, Feb 8, 2021 at 12:37 PM Jessica Clarke >> wrote: >> >> >> >> On 8 Feb 2021, at 19:15, Mateusz Guzik wrote: >> >>> >> >>> The branch main has been updated by mjg: >> >>> >> >>> URL: >> https://cgit.FreeBSD.org/src/commit/?id=3Daf366d353b84bdc4e730f0fc563853= abc338271c >> >>> >> >>> commit af366d353b84bdc4e730f0fc563853abc338271c >> >>> Author: Mateusz Guzik >> >>> AuthorDate: 2021-02-08 17:01:48 +0000 >> >>> Commit: Mateusz Guzik >> >>> CommitDate: 2021-02-08 19:15:21 +0000 >> >>> >> >>> amd64: implement strlen in assembly >> >>> >> >>> The C variant in libkern performs excessive branching to find the >> >>> non-zero byte instead of using the bsfq instruction. The same code >> >>> patched to use it is still slower than the routine implemented her= e >> >>> as the compiler keeps neglecting to perform certain optimizations >> >>> (like using leaq). >> >>> >> >>> On top of that the routine can is a starting point for copyinstr >> >>> which operates on words instead of bytes. >> >>> >> >>> Tested with glibc test suite. >> >>> >> >>> Sample results (calls/s): >> >>> >> >>> Haswell: >> >>> $(perl -e "print 'A' x 3"): >> >>> stock: 211198039 >> >>> patched:338626619 >> >>> asm: 465609618 >> >>> >> >>> $(perl -e "print 'A' x 100"): >> >>> stock: 83151997 >> >>> patched: 98285919 >> >>> asm: 120719888 >> >>> >> >>> AMD EPYC 7R32: >> >>> $(perl -e "print 'A' x 3"): >> >>> stock: 282523617 >> >>> asm: 491498172 >> >>> >> >>> $(perl -e "print 'A' x 100"): >> >>> stock: 114857172 >> >>> asm: 112082057 >> >> >> >> No Reviewed by? More than one pair of eyes on non-trivial assembly is >> >> almost always a good idea. >> >> >> >> Jess >> >> >> >> _______________________________________________ >> >> dev-commits-src-main@freebsd.org mailing list >> >> https://lists.freebsd.org/mailman/listinfo/dev-commits-src-main >> >> To unsubscribe, send any mail to " >> dev-commits-src-main-unsubscribe@freebsd.org" >> >>