From nobody Sat May 18 16:37:23 2024 X-Original-To: dev-commits-src-main@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 4VhTyW1r31z5L6SV for ; Sat, 18 May 2024 16:37:39 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: from mail-lf1-x131.google.com (mail-lf1-x131.google.com [IPv6:2a00:1450:4864:20::131]) (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 4VhTyW0r54z4GGQ for ; Sat, 18 May 2024 16:37:39 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Authentication-Results: mx1.freebsd.org; none Received: by mail-lf1-x131.google.com with SMTP id 2adb3069b0e04-5238cb1e3bbso1882362e87.3 for ; Sat, 18 May 2024 09:37:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bsdimp-com.20230601.gappssmtp.com; s=20230601; t=1716050256; x=1716655056; darn=freebsd.org; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=QQFB2q0gAoQr9/XMNQDXCI4Rc5un2TKSc/bJtOOvqTE=; b=ci3WSZMjLcF/M+mvNnbB9c4PSenDU7adujLPuxtoBgYhJHag+dHo+KbmR1dMwaKOHv vUWpJ39hO9ZpzDnXdoLI9JZ6pMSL6TBfs+biBmfFID4FSeLc7g6WM9feQs+W9ZB/8yhv rzAmMvN9fp9x9U3lXNyvK5sjJByKck4uV6UFcJ37X5/XeYwBe0qTDTXtZxkYV2dkoprF tW8CstI2ko32e2dirYztSRE53Q9OgzcvyiiYuCQUZyswLohM8OO1Gl0hfbyotnfPC2NO HuwYVqeVlNxrLh7++rM2F5HmypUsq65uWMlXmCuKpQ5kXSEajUK3WI7+lhcuOuSEm4ac DddQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1716050256; x=1716655056; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=QQFB2q0gAoQr9/XMNQDXCI4Rc5un2TKSc/bJtOOvqTE=; b=htpBbIE6IrrYLztVDNHWfXT+DOJ1MzGxVmAIlYXtS73Vpt2il3jFuwvJIJxLi3HR71 n+npFgrLq2qUITcrBS/eA0ETQw03zDE6xClKv8cWnJJqUzGgbMXVmtKXJNmZyl8iNiPK nfyT4BtK0DUjfDfMsytoLc/sfBGv5e+vQ/7fTEplC4q5wgSvd5TGXjfGojm2MzELubQq jjaKOIjo2JiFjnCZeaHYYgBRU6B1Weui0jgekxbp5ILHWFPle05wgUVGwox/o2hPkrZi ryG922Vz7/aUArhL6omOydCrReHikAhbmOo6TrUHjcg8JkGPKenkWH50nVaGLUIeSJ1t TMDw== X-Forwarded-Encrypted: i=1; AJvYcCXGKHcbWrrz8eBT1CtC2TwEWUZDQntrpp8uhTB+oJJQlR/woPfINmKmvjBFvjbG7kp33V6q4qEjo4Pv8pCXb/WSV1AQJQjAKnqMXR9SXZm7Rw== X-Gm-Message-State: AOJu0Yw8rJSV/xYqwPVuAU25lGWV6X0j0YHHAArympjxVenaLv8Rzy1q 1n/kQNOy8ETzWrd5o1GbnrRULdmg7fZKhyN0+FDzibukHhaZNpW6tMRe2MgP2hpOzOO7QM/V2jw 302QXVMXZcHKZhK/8k8r2+8vnjtwPc+lBhm3Q+A== X-Google-Smtp-Source: AGHT+IEMJGZ+MWz8NBfqGZLQ8iEZnhdVOXFLlFgeAqYY47Zovwh482GLqZFrvSCiZUJiWitZp17lvX8zoEj4dC7n/nQ= X-Received: by 2002:a05:6512:3194:b0:523:b19a:25fe with SMTP id 2adb3069b0e04-523b19a28a8mr7174655e87.6.1716050255404; Sat, 18 May 2024 09:37:35 -0700 (PDT) List-Id: Commit messages for the main branch of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-main List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-main@freebsd.org Sender: owner-dev-commits-src-main@FreeBSD.org MIME-Version: 1.0 References: <202405181551.44IFpenT061023@gitrepo.freebsd.org> <0100018f8c718fa1-b3f56c7f-bc2b-42c3-9a8a-03cd3a5e08d2-000000@email.amazonses.com> In-Reply-To: <0100018f8c718fa1-b3f56c7f-bc2b-42c3-9a8a-03cd3a5e08d2-000000@email.amazonses.com> From: Warner Losh Date: Sat, 18 May 2024 10:37:23 -0600 Message-ID: Subject: Re: git: 3bb5428ad643 - main - rc.conf.5: remove obsolete advice about kld_list To: Colin Percival Cc: Alan Somers , src-committers , "" , "" Content-Type: multipart/alternative; boundary="000000000000e406050618bd1521" X-Spamd-Bar: ---- X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[]; ASN(0.00)[asn:15169, ipnet:2a00:1450::/32, country:US] X-Rspamd-Queue-Id: 4VhTyW0r54z4GGQ --000000000000e406050618bd1521 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Sat, May 18, 2024, 10:03=E2=80=AFAM Colin Percival wrote: > On 5/18/24 08:51, Alan Somers wrote: > > commit 3bb5428ad643e38dd755c8d66c8ac2ae8f7575b5 > > > > rc.conf.5: remove obsolete advice about kld_list > > > > Loading modules via kld_list is no longer substantially faster tha= n > via > > loader.conf. > Where did you benchmark this? I can believe that performance is similar > using UEFI, but on systems booting with BIOS doing I/O from the loader is > very slow because the 20-bit address space forces us to use small I/Os. > The performance problem was there was no buffer cache in the boot loader at all. BIOS is still a little slower, but ot that much slower on anything made in the last decade.... It used to be like 10-20s faster. Now it's less than a second, even for BIOS booting. And UEFI is about the same. The block cache is responsible for most of this. And BIOS doesn't matter so much these days: it is still in use, but few people use it and the IO speed when they do is DMA speeds not REPS INB speeds. Plus it causes some memory fragmentation and there are subtle bugs with it (like kld_list=3D"uhid ums" working but kld_list=3D"ums uhid" failing). Warner --=20 > Colin Percival > FreeBSD Release Engineering Lead & EC2 platform maintainer > Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoi= d > --000000000000e406050618bd1521 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


On Sat, May 18, 2024, 10:03=E2=80=AFAM Colin Percival = <cperciva@tarsnap.com> wrote:
On 5/18/24 08:51, Alan Somers wrote:
> commit 3bb5428ad643e38dd755c8d66c8ac2ae8f7575b5
>
>=C2=A0 =C2=A0 =C2=A0 rc.conf.5: remove obsolete advice about kld_list >=C2=A0 =C2=A0 =C2=A0
>=C2=A0 =C2=A0 =C2=A0 Loading modules via kld_list is no longer substant= ially faster than via
>=C2=A0 =C2=A0 =C2=A0 loader.conf.
Where did you benchmark this?=C2=A0 I can believe that performance is simil= ar
using UEFI, but on systems booting with BIOS doing I/O from the loader is very slow because the 20-bit address space forces us to use small I/Os.
=

The = performance problem was there was no buffer cache in the boot loader at all= . BIOS is still a little slower, but=C2=A0 ot that much slower on anything = made in the last decade....

It used to be like 10-20s faster. Now it's less than a second, even= for BIOS booting. And UEFI is about the same. The block cache is responsib= le for most of this. And BIOS doesn't matter so much these days: it is = still in use, but few people use it and the IO speed when they do is DMA sp= eeds not REPS INB speeds.

Plus it causes some memory fragmentation and there are subtle bugs with i= t (like kld_list=3D"uhid ums" working but kld_list=3D"ums uh= id" failing).

Warne= r

--
Colin Percival
FreeBSD Release Engineering Lead & EC2 platform maintainer
Founder, Tarsnap | www.tarsnap.com | Online backups = for the truly paranoid
--000000000000e406050618bd1521--