From nobody Thu Sep 1 23:36:44 2022 X-Original-To: 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 4MJcwC3vK8z4b2vj for ; Thu, 1 Sep 2022 23:39:55 +0000 (UTC) (envelope-from david@catwhisker.org) Received: from mx.catwhisker.org (mx.catwhisker.org [107.204.234.170]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4MJcwB4Ttgz44dm for ; Thu, 1 Sep 2022 23:39:54 +0000 (UTC) (envelope-from david@catwhisker.org) Received: from albert.catwhisker.org (localhost [127.0.0.1]) by albert.catwhisker.org (8.16.1/8.15.2) with ESMTP id 281NdrFn066473 for ; Thu, 1 Sep 2022 23:39:53 GMT (envelope-from david@albert.catwhisker.org) Received: (from david@localhost) by albert.catwhisker.org (8.16.1/8.16.1/Submit) id 281NdrNQ066472 for hackers@freebsd.org; Thu, 1 Sep 2022 16:39:53 -0700 (PDT) (envelope-from david) Resent-From: David Wolfskill Resent-Date: Thu, 1 Sep 2022 16:39:53 -0700 Resent-Message-ID: Resent-To: hackers@freebsd.org X-Original-To: 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 4MJcrh4LJKz4b2fS for ; Thu, 1 Sep 2022 23:36:52 +0000 (UTC) (envelope-from david@catwhisker.org) Received: from mx.catwhisker.org (mx.catwhisker.org [107.204.234.170]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4MJcrg3yq9z44dh for ; Thu, 1 Sep 2022 23:36:51 +0000 (UTC) (envelope-from david@catwhisker.org) Received: from albert.catwhisker.org (localhost [127.0.0.1]) by albert.catwhisker.org (8.16.1/8.15.2) with ESMTP id 281NaiC5066410; Thu, 1 Sep 2022 23:36:44 GMT (envelope-from david@albert.catwhisker.org) Received: (from david@localhost) by albert.catwhisker.org (8.16.1/8.16.1/Submit) id 281Nai0a066409; Thu, 1 Sep 2022 16:36:44 -0700 (PDT) (envelope-from david) Date: Thu, 1 Sep 2022 16:36:44 -0700 From: David Wolfskill To: hackers@freebsd.org Subject: Reasonable/sane limits for kern.msgbufsize? Message-ID: List-Id: Technical discussions relating to FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-hackers List-Help: List-Post: List-Subscribe: List-Unsubscribe: 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 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="RuaTJOZqeFO4W2mx" Content-Disposition: inline X-ThisMailContainsUnwantedMimeParts: N X-Rspamd-Queue-Id: 4MJcwB4Ttgz44dm X-Spamd-Bar: ---- Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=pass (mx1.freebsd.org: domain of david@catwhisker.org designates 107.204.234.170 as permitted sender) smtp.mailfrom=david@catwhisker.org X-Spamd-Result: default: False [-4.56 / 15.00]; SIGNED_PGP(-2.00)[]; SUBJECT_ENDS_QUESTION(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_MEDIUM(-1.00)[-1.000]; NEURAL_HAM_SHORT(-1.00)[-1.000]; MIME_GOOD(-0.20)[multipart/signed,text/plain]; R_SPF_ALLOW(-0.20)[+ip4:107.204.234.170:c]; MAILLIST(-0.15)[generic]; HAS_LIST_UNSUB(-0.01)[]; ARC_NA(0.00)[]; MLMMJ_DEST(0.00)[hackers@freebsd.org]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+,1:+,2:~]; R_DKIM_NA(0.00)[]; ASN(0.00)[asn:7018, ipnet:107.192.0.0/12, country:US]; DMARC_NA(0.00)[catwhisker.org]; RCVD_TLS_LAST(0.00)[]; RCPT_COUNT_ONE(0.00)[1]; FROM_HAS_DN(0.00)[]; FREEFALL_USER(0.00)[david]; MID_RHS_MATCH_FROMTLD(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; TO_DN_NONE(0.00)[]; PREVIOUSLY_DELIVERED(0.00)[hackers@freebsd.org]; RCVD_COUNT_SEVEN(0.00)[7] X-ThisMailContainsUnwantedMimeParts: N --RuaTJOZqeFO4W2mx Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Empirically, I have found that for dmesg.boot to contain the full dmesg =66rom a verbose boot on one of my machines, starting from: ---<>--- APIC: Using the MADT enumerator. Copyright (c) 1992-2021 The FreeBSD Project. =2E.. I need to increase kern.msgbufsize to above 200KiB (204800); so far, 262144 (256KiB) seems to work for stable/12. (Actual size of /var/run/dmesg.boot just now was 216929 -- 212KiB.) Note that the default value is 96KiB (98304). In this particular case, the machine has 256GiB RAM -- but kernel address space (I expect) remains a constrained resource. How much trouble am I asking for if I set kern.msgbufsize=3D262144 in /boot/laoder.conf? It might be cool to be able to do that only for a verbose boot, and have a somewhat more reasonable value for a non-verbose boot.... [Rationale: I build FreeBSD often -- tracking head, stable/13 and (currently) stable/12 daily. I place salient information on a Web site; that includes a copy of /var/run/dmesg.boot -- from a verbose boot. But I noted a while back that much of the first part of the latter was missing; I only found out "how much" a few minutes ago.] Peace, david --=20 David H. Wolfskill david@catwhisker.org See "Truth Social"? Read it as "Pravda" -- and adjust expectations accordi= ngly. See https://www.catwhisker.org/~david/publickey.gpg for my public key. --RuaTJOZqeFO4W2mx Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iNUEARYKAH0WIQSr0Kzv+UJRY3wfOii0+6PfV4Ix1AUCYxFCDF8UgAAAAAAuAChp c3N1ZXItZnByQG5vdGF0aW9ucy5vcGVucGdwLmZpZnRoaG9yc2VtYW4ubmV0QUJE MEFDRUZGOTQyNTE2MzdDMUYzQTI4QjRGQkEzREY1NzgyMzFENAAKCRC0+6PfV4Ix 1Hu+AP4gw5agBu/cxC8BJEXbMzoT8ZGkbCt3JFYPVGKa/x5AtgEA3gXfX9oAb8Qj bXKCc9GF1tmb+fQySp92HEkbS7xmZgQ= =bf91 -----END PGP SIGNATURE----- --RuaTJOZqeFO4W2mx--