From nobody Thu Jun 23 15:26:43 2022 X-Original-To: freebsd-hackers@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 1C81F87E928 for ; Thu, 23 Jun 2022 15:27:02 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: from mail-vk1-xa2c.google.com (mail-vk1-xa2c.google.com [IPv6:2607:f8b0:4864:20::a2c]) (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 1D4" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4LTPHn3625z4p7T for ; Thu, 23 Jun 2022 15:27:01 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: by mail-vk1-xa2c.google.com with SMTP id b4so6561176vkh.6 for ; Thu, 23 Jun 2022 08:27:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bsdimp-com.20210112.gappssmtp.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=qxFxv8IvLG+ov6ZRo0DoGnhRxmG3ZMd9j093J1e69fI=; b=njM8QFzMRbV5AAzG+krrWcjh+zEBvwtgEPTk7yERpaozVb4TlkHY+Y3nkHzLS45T48 81kLaG1AOb83/NoedOhdtWhJ+exlGdvfhUTKwNj70Q9b8kuUUiFQU0TnsGSja/8Omn4g v0Usx1xndNT4Qf+jevF61jxqf0LRuGcWyhoEs3FOwWszge7vQTZQYK0kPU8KkUrpzh3v QD6+wH2LqNgMKoxBeUYc206hx9jGdXUMtElTgfMNF8xg9bUrizTNKOEdMd6IyaJWagJx cKDc1P3DI/6Qq6M7BWGh7nkdlNbNqR+9Ojwj0CjGEDOmaWbi58MUVRIyYwr41spHlBF6 fhqQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=qxFxv8IvLG+ov6ZRo0DoGnhRxmG3ZMd9j093J1e69fI=; b=7YrQipxGU+gqJnqvL5qJ04vJfqGGYOx+dRG8FDpAah1Un0mMMHdIR8pG367xUeK+7/ Jupw2NdYHHFpM6RchvvbZbGt7P5Gn31T6T0mKF9599206tJpwaeNSzOCJg0Nm4OS7anB ty/8L0HMSRflIlug6vQ3AJcLlyMei8xHSN7leT9YxKqe7UGn15xASCzasm7Vx4OSCoWd tfWzV3JHASNsxPQaQ177fwwxtVBD2uAxl8Ym7IIIPLK30EOoeuHGmIs3uH2Zqxq8sbQ6 qJnBQPsnvOF36VZbdrS48AbYW4GveUhhHLcSbKgPBp9LLkst9tY+Hmy1SyoyyQUZZhcR F2Cw== X-Gm-Message-State: AJIora8CnZ62nOSsblU6KRY5gdGlr604cHGjRps4G9GkLHe7TSdmd8Nd PPBR3jvyI4n1OEqgigsOW5jJBIZmOE7m8YygydIQ3w== X-Google-Smtp-Source: AGRyM1vGJutcCJ/L2UukbX6VUAa2dLLN39ITwYe0K03FvbnemA5Pjhyxctn142N+bTEZJrbsBj+FnKWuRLJcokDGC/0= X-Received: by 2002:a05:6122:143a:b0:36c:177c:4f97 with SMTP id o26-20020a056122143a00b0036c177c4f97mr10799953vkp.23.1655998015079; Thu, 23 Jun 2022 08:26:55 -0700 (PDT) List-Id: Technical discussions relating to FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-hackers List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-hackers@freebsd.org MIME-Version: 1.0 References: <20211126160454.3eb827365a02103169ab9adc@bidouilliste.com> <20220621201924.e9b96876c947140ac1f3b7a4@bidouilliste.com> <3d09c86a-9840-f8bf-4725-8098d958a01d@plan-b.pwste.edu.pl> <202206211901.25LJ1uBd067376@critter.freebsd.dk> <20220622044923.6e2fac81c1e8205872d9de11@bidouilliste.com> <6b7997d6-f8ed-c4e4-91eb-da9b20eb0a14@grosbein.net> In-Reply-To: <6b7997d6-f8ed-c4e4-91eb-da9b20eb0a14@grosbein.net> From: Warner Losh Date: Thu, 23 Jun 2022 09:26:43 -0600 Message-ID: Subject: Re: Reasons for keeping sc(4) and libvgl ? To: Eugene Grosbein Cc: Steve Kargl , Stefan Blachmann , Emmanuel Vadot , Ed Maste , Poul-Henning Kamp , FreeBSD Hackers Content-Type: multipart/alternative; boundary="000000000000701be205e21f1552" X-Rspamd-Queue-Id: 4LTPHn3625z4p7T X-Spamd-Bar: - Authentication-Results: mx1.freebsd.org; dkim=pass header.d=bsdimp-com.20210112.gappssmtp.com header.s=20210112 header.b=njM8QFzM; dmarc=none; spf=none (mx1.freebsd.org: domain of wlosh@bsdimp.com has no SPF policy when checking 2607:f8b0:4864:20::a2c) smtp.mailfrom=wlosh@bsdimp.com X-Spamd-Result: default: False [-1.98 / 15.00]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-0.99)[-0.988]; R_DKIM_ALLOW(-0.20)[bsdimp-com.20210112.gappssmtp.com:s=20210112]; FROM_HAS_DN(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; NEURAL_HAM_LONG(-1.00)[-0.999]; MIME_GOOD(-0.10)[multipart/alternative,text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-hackers@freebsd.org]; DMARC_NA(0.00)[bsdimp.com]; TO_MATCH_ENVRCPT_SOME(0.00)[]; TO_DN_ALL(0.00)[]; DKIM_TRACE(0.00)[bsdimp-com.20210112.gappssmtp.com:+]; NEURAL_HAM_SHORT(-1.00)[-0.996]; RCPT_COUNT_SEVEN(0.00)[7]; RCVD_IN_DNSWL_NONE(0.00)[2607:f8b0:4864:20::a2c:from]; MLMMJ_DEST(0.00)[freebsd-hackers]; FORGED_SENDER(0.30)[imp@bsdimp.com,wlosh@bsdimp.com]; R_SPF_NA(0.00)[no SPF record]; MIME_TRACE(0.00)[0:+,1:+,2:~]; SUBJECT_ENDS_QUESTION(1.00)[]; 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)[]; FREEMAIL_CC(0.00)[troutmask.apl.washington.edu,gmail.com,bidouilliste.com,freebsd.org,phk.freebsd.dk] X-ThisMailContainsUnwantedMimeParts: N --000000000000701be205e21f1552 Content-Type: text/plain; charset="UTF-8" On Tue, Jun 21, 2022 at 11:46 PM Eugene Grosbein wrote: > 22.06.2022 12:34, Warner Losh wrote: > > > On Tue, Jun 21, 2022, 10:59 PM Steve Kargl < > sgk@troutmask.apl.washington.edu > > wrote: > > > > On Tue, Jun 21, 2022 at 10:55:01PM -0600, Warner Losh wrote: > > > On Tue, Jun 21, 2022, 9:47 PM Stefan Blachmann < > sblachmann@gmail.com > wrote: > > > > > > > I would kindly ask to stop pushing for removal of sc. > > > > > > > > > > It will die soon enough if it doesn't become giant locked soon... > > > > > > Warner > > > > > > > Are you deleting vt, too? > > > > > > The project likely has resources to remove giant from only one console > driver. That will almost certainly be vt. > > Then sc(4) should stay giant-locked until vt(4) implements all features > called-for sc. > After all, sc is not network nor I/O "hot path". > Giant is being removed entirely, and with it all straggler drivers that aren't converted by the removal date. There's no fixed date for this, at the present time, but I'm about to commit changes that make it impossible for new code to reference Giant. Having Giant, at all, causes slow downs elsewhere in the system, which is why we're pushing to remove it entirely. sc(4) has lots of giant use, and is intertwingled with atkbdc, atkbd and ms in ways that are tricky to unwind (though some work to unwind ms has been committed). "All" features won't be a gating factor, unfortunately, unless somebody steps up and (a) does them or (b) actively funds the work. vt(4) is complete enough that straggler issues won't gate a future sc(4) removal when Giant goes away. Especially since many of the issues are on hard to obtain platforms and/or cards that aren't entirely mainstream. In an ideal world, we'd not have to make such choices, but the project must and it's better to be honest about it than to give people false hope. Warner --000000000000701be205e21f1552 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


=
On Tue, Jun 21, 2022 at 11:46 PM Euge= ne Grosbein <eugen@grosbein.net> wrote:
22.= 06.2022 12:34, Warner Losh wrote:

> On Tue, Jun 21, 2022, 10:59 PM Steve Kargl <sgk@troutmask.apl.washington= .edu <mailto:sgk@troutmask.apl.washington.edu>> wrote:
>
>=C2=A0 =C2=A0 =C2=A0On Tue, Jun 21, 2022 at 10:55:01PM -0600, Warner Lo= sh wrote:
>=C2=A0 =C2=A0 =C2=A0> On Tue, Jun 21, 2022, 9:47 PM Stefan Blachmann= <sblachmann@g= mail.com <mailto:sblachmann@gmail.com>> wrote:
>=C2=A0 =C2=A0 =C2=A0>
>=C2=A0 =C2=A0 =C2=A0> > I would kindly ask to stop pushing for re= moval of sc.
>=C2=A0 =C2=A0 =C2=A0> >
>=C2=A0 =C2=A0 =C2=A0>
>=C2=A0 =C2=A0 =C2=A0> It will die soon enough if it doesn't beco= me giant locked soon...
>=C2=A0 =C2=A0 =C2=A0>
>=C2=A0 =C2=A0 =C2=A0> Warner
>=C2=A0 =C2=A0 =C2=A0>
>
>=C2=A0 =C2=A0 =C2=A0Are you deleting vt, too?
>
>
> The project likely has resources to remove giant from only one console= driver. That will almost certainly be vt.

Then sc(4) should stay giant-locked until vt(4) implements all features cal= led-for sc.
After all, sc is not network nor I/O "hot path".
=

Giant is being removed entirely, and with it all stragg= ler drivers that aren't converted by the removal date.
There&= #39;s no fixed date for this, at the present time, but I'm about to com= mit changes that make it impossible
for new code to reference Gia= nt. Having Giant, at all, causes slow downs elsewhere in the system, which<= /div>
is why we're pushing to remove it entirely. sc(4) has lots of= giant use, and is intertwingled with atkbdc, atkbd
and ms in way= s that are tricky to unwind (though some work to unwind ms has been committ= ed).

"All" features won't be a gatin= g factor, unfortunately, unless somebody steps up and (a) does them
or (b) actively funds the work. vt(4) is complete enough that straggler = issues won't gate a future sc(4)
removal when Giant goes away= . Especially since many of the issues are on hard to obtain platforms
=
and/or cards that aren't entirely mainstream. In an ideal world, w= e'd not have to make such choices,
but the project must and i= t's better to be honest about it than to give people false hope.
<= div>
Warner
--000000000000701be205e21f1552--