Date: Mon, 7 Sep 2015 23:29:44 +0200 From: Pawel Jakub Dawidek <pjd@FreeBSD.org> To: Warner Losh <imp@bsdimp.com> Cc: "freebsd-arch@freebsd.org" <arch@FreeBSD.org> Subject: Re: exporting INVARIANTS easily Message-ID: <20150907212943.GB1778@garage.freebsd.pl> In-Reply-To: <EC6B1705-8189-436C-9E47-20E8A4AF8488@bsdimp.com> References: <EC6B1705-8189-436C-9E47-20E8A4AF8488@bsdimp.com>
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--24zk1gE8NUlDmwG9 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Aug 26, 2015 at 11:20:06AM -0600, Warner Losh wrote: > Greetings, >=20 > Many of the performance eating features are exported via some kind of sys= ctl, usually > patterned after the case of witness as debug.foo. INVARIANTS isn=E2=80=99= t one of those > features. >=20 > https://reviews.freebsd.org/D3488 >=20 > implements debug.invariants. Please comment. >=20 > I=E2=80=99d thought about adding it to the kern.features sysctl, but thou= ght better of it since it > isn=E2=80=99t a facility that people can use. >=20 > If you include the kernel config in the kernel, you can get this informat= ion via > config -x | grep INVARIANTS > but not all kernels do that. This is more robust. >=20 > I also know that you can load some modules compiled INVARIANTS when the b= ase > kernel isn=E2=80=99t built that way and this won=E2=80=99t reflect that. = There=E2=80=99s no good want to include > that information and is an uncommon use case. >=20 > Our use case? We have a raft of test machines. Most run without INVARIANT= S since > we want to characterize the performance of the release under test. Some a= re running > INVARIANTS since we want to test the robustness as well, even at the expe= nse of > some performance. To ensure we don=E2=80=99t accidentally include INVARIA= NTS systems > in the performance number, we=E2=80=99ve adding a key to an internal data= base that=E2=80=99s driven > off this sysctl. >=20 > Comments? As long as the ultimate goal is to have INVARIANTS in GENERIC I'm all for it! I use to run even production machines with INVARIANTS, which was helpful to catch VirtualBox's kernel memory corruption, but we've moved to GENERIC since I wanted to use freebsd-update. Having INVARIANTS in GENERIC would be great. --=20 Pawel Jakub Dawidek http://www.wheelsystems.com FreeBSD committer http://www.FreeBSD.org Am I Evil? Yes, I Am! http://mobter.com --24zk1gE8NUlDmwG9 Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCgAGBQJV7gHHAAoJEJVLhSuxKFt1JicP/RfLmso/BftpGykpO2hJPuuJ sNqQjroFMlrQrIzu/rAWrJ7PPffgDdmCtmAZ4+cpVRUodU7A15ZIXdNghGgaIhhy aplcV1uT967vpYWMTjJ1UPNi2qWLTcV2Dp0EoGCCUshUXN9M+43UJSEEd1fokywd fFRlLA5yazUnerDoZmetHanNEcumKhb7QFdAcYpBAxkBV5j3O5jEFXrE+/K7PbBy sdH1YWBf1j8VSvBrLMlQRC52GNBHYnlSWaobfOj1ng5hRrh/g+1XDoYOqPQerNSg PO+mlAsL0NgjvBY7aVc1PBAsj+ytK1HyDyf9/W3jz4J0WPJshnn7Z20S64aLfxXg IhSWkbd1ApGXDz5PunsLxmfsKPWGeaNUmZiP+pluajd5/4q799bXjBPCm+ZdnXdR K1NdTPBQ/ED8jXRmbgfqKFGDLQXelAI4lu9z8Y9iBB+oEIi9nHflN83TZSoal5Rd Rf0QDXcgnH+U9gBBClEgiLP/oqTQnto2tTMI4pDYzbOQ9Keb6wKfWRkCziyuUqMY Pi+r6MoWi5rvNEipvFMMoykrYD+bPXOD441yzrHbA3w4SJH4xuQ7uCE/9S89Y2zS uHOFzkL979RJ/RK1wkT72C5bjGzfzwXPiolWqlvwzwKd1xH15o9Dmuq+KK71FVel wVMa7nTJTxkjQoUsQ3ru =diDM -----END PGP SIGNATURE----- --24zk1gE8NUlDmwG9--
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