Date: Mon, 12 Dec 2016 22:29:44 -0700 From: Warner Losh <wlosh@bsdimp.com> To: Peter Jeremy <peter@rulingia.com> Cc: Warner Losh <imp@bsdimp.com>, Ed Schouten <ed@nuxi.nl>, FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: Sysctl as a Service, or: making sysctl(3) more friendly for monitoring systems Message-ID: <B9B40604-B8E6-42A8-B5CB-41EDAE025911@bsdimp.com> In-Reply-To: <20161213052759.GP61036@server.rulingia.com> References: <CABh_MKk87hJTsu1ETX8Ffq9E8gqRPELeSEKzf1jKk_wwUROgAw@mail.gmail.com> <eea0aa41-2bbc-0ddc-d951-f495c5ba2341@freebsd.org> <200A5D70-24CE-4843-B99D-E10A2AF4F68F@FreeBSD.org> <CABh_MKkAoTj4wA9oTz-fK0rokgMfuiUWpLt6t=qRXy6vvCh7rg@mail.gmail.com> <CANCZdfrjsLdMoZ9Eg19-mEbyxUefJxUmeq=cT_bagrJqzWnUOg@mail.gmail.com> <20161213052759.GP61036@server.rulingia.com>
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--Apple-Mail=_15F5C561-94BD-43D4-A6BE-9BDA98F3F57C Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii > On Dec 12, 2016, at 10:27 PM, Peter Jeremy <peter@rulingia.com> wrote: >=20 > On 2016-Dec-12 17:57:07 -0700, Warner Losh <imp@bsdimp.com> wrote: >> On Mon, Dec 12, 2016 at 6:34 AM, Ed Schouten <ed@nuxi.nl> wrote: >>> $ time ./prometheus_sysctl_exporter | wc -l >>> 0.00 real 0.00 user 0.00 sys >>> 3162 >>>=20 >>> If our sysctl tree would get substantially larger at some point, we >>> should of course revisit this. >>=20 >> That sounds cool. I'd love to see what you came up with to get those = results. >=20 > I think that's impressive as well. >=20 >> While we're here... there's one thing I'd love to see from a >> hypothetical /dev/sysctl... When a sysctl value changes (or some >> subset), I'd like it to appear on a read-channel. That way, I could >> monitor temperature w/o needing to constantly poll for changes, for >> example. >=20 > That sounds like a job for kqueue(2), though it would need to be = plumbed > through. The biggest problem I see is that nothing in the sysctl = mechanism > has any way of reporting that a value has changed and so consumers of = that > data should re-check. This means that you'd probably just wind up = polling > in the kernel. It does if you had a read-channel :) > Note that Prometheus is designed around regularly polling the systems = it's > monitoring so this sort of functionality wouldn't benefit it. True. Warner --Apple-Mail=_15F5C561-94BD-43D4-A6BE-9BDA98F3F57C Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQIcBAEBCgAGBQJYT4dJAAoJEGwc0Sh9sBEAkpMQAOBhtysDd5i/F68ZAexjHOHb CTeFvurGrJiLxygoJKHavuT5m+Onf8Oz4/zAFokw2Tcxe1wBtBlR6buAZ7Wqfo6S T6rmVPWP5U26F+mDWB57taqHPg5Ja8AfVvFTqSQi5wDGm0MvhhaH4w8MikgFOJ/l B2AlwJqFE7v/RLexpH7q57glPJY5Jj06OpDSIP2c4LaS+/8Mb2qZzoEHs8rNrBtk J0a36M1yAzp7sS7gO7zXJ0mH94xOojCl8p/AI+hQZV7bedk08YMQoetC+ZTIb/3n bA8nr1d8uxUJ8PSRGZX+FkuBefMb+Cc63VkMH9TvARf70ee6nSQYa1PVWofhssy9 7tkArgbKtQrg5pQEVmC8BOnHj28H7Ae3FEu8Esst945UTJa+pb3ZGustGdj9zwcL OK4EfGVTGN4EXPgqw6Ym/HPp28R+uz5RItPlpxannqaGTdJGvE0WMihUB7TAPAi2 IStamgs2wPY7BCZ5ixZQLbd5c0vF2jKoNDWIiGWnMqF98boSX+s5l0Gk+g6MDE8W lTA+lY0Je+XZFBKsFbEoUDH9pKTUUWKRbc1PRY4AgmOA6gRC2qD6dSHJmfXCP5yT XPlZN6q99TL8fP1pLgsl1pk1CjsD+BZq6D+2AE+tvGU/xAXKRVcUEAZv0SO9Sdrt Wy+lHinIFFRsbjENICeA =0KpV -----END PGP SIGNATURE----- --Apple-Mail=_15F5C561-94BD-43D4-A6BE-9BDA98F3F57C--
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