Date: Wed, 26 Aug 2015 11:20:06 -0600 From: Warner Losh <imp@bsdimp.com> To: "freebsd-arch@freebsd.org" <arch@FreeBSD.org> Subject: exporting INVARIANTS easily Message-ID: <EC6B1705-8189-436C-9E47-20E8A4AF8488@bsdimp.com>
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[-- Attachment #1 --] Greetings, Many of the performance eating features are exported via some kind of sysctl, usually patterned after the case of witness as debug.foo. INVARIANTS isn’t one of those features. https://reviews.freebsd.org/D3488 implements debug.invariants. Please comment. I’d thought about adding it to the kern.features sysctl, but thought better of it since it isn’t a facility that people can use. If you include the kernel config in the kernel, you can get this information via config -x | grep INVARIANTS but not all kernels do that. This is more robust. I also know that you can load some modules compiled INVARIANTS when the base kernel isn’t built that way and this won’t reflect that. There’s no good want to include that information and is an uncommon use case. Our use case? We have a raft of test machines. Most run without INVARIANTS since we want to characterize the performance of the release under test. Some are running INVARIANTS since we want to test the robustness as well, even at the expense of some performance. To ensure we don’t accidentally include INVARIANTS systems in the performance number, we’ve adding a key to an internal database that’s driven off this sysctl. Comments? Warner [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Comment: GPGTools - https://gpgtools.org iQIcBAEBCgAGBQJV3fVGAAoJEGwc0Sh9sBEAfNIQALys9LOQgbaztLjuACdJe7NH gpVlHIbcrwAk6+hFmIEVOvRHbwryCoTpII4I2dQexD8Or3NEzXzCXhmzTXY91NQ8 ud/rR74JekcALMPP4MkX+qCY/OeoSsE6MOFepcrctRAeujZvDa6y7FLeyhl7acHr xBLSsr+mPk2IFgYImTaiEvcz3zZxVp2jentW8LoPSQGlnRguypqLgoSnZiRb5sow dIuk+Qt6iQhvqIXXzceJJj3bfDaMp52aeGKn02fq5oZDLRCD/SHs4wjUymMb5tP6 uUnF6zQz8bKcGmLf/3OqIzCm58lbMiif4rGN9BpgXpyMv7vd62tb3yIVruY3nV83 MTVMW2TfAqyyY9liZhFdQtHsoxKv/qXX8xXZjv56OU/VSvM53sT09Q+cVeVcY8d0 a00++wgwHyzl5Bqe5H+TPsOpNgUeE8Jfq24KxToqU21YCw+S/iPt6nVa3mCye4GQ 9PJaruTaSAvvFoE8PivAWTJ7Ro53bzIrKFyJDFjANIOr+zk61fd/YOuJ/LZZGD4E Je8MUKJEYKPk7YfQKrjcgEdC2+CQpUzlXSHaok7DXRdIwt8l7ozlUqL6/qobtj0W rAOJl4C4wBcZCITZGjL5qtFvBsPMdXCluhajsNtis4vZwQf3fyI022g6DY3osvCw XoV1XnTbuJNT3Rf7UBQM =D55O -----END PGP SIGNATURE-----help
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