Date: Tue, 17 Oct 2006 14:02:18 +0930 From: Greg 'groggy' Lehey <grog@FreeBSD.org> To: Olivier Nicole <on@cs.ait.ac.th> Cc: freebsd-questions@FreeBSD.org Subject: Re: User vs Kernel mode Message-ID: <20061017043218.GP96445@wantadilla.lemis.com> In-Reply-To: <200610170252.k9H2qHaD012527@banyan.cs.ait.ac.th> References: <200610170235.k9H2ZElx012419@banyan.cs.ait.ac.th> <20061017024102.GO96445@wantadilla.lemis.com> <200610170252.k9H2qHaD012527@banyan.cs.ait.ac.th>
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--N5iGxCIPT7YMRg16 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tuesday, 17 October 2006 at 9:52:17 +0700, Olivier Nicole wrote: >> Processes always start in kernel mode, because they're started by the >> kernel. They typically spend most of their time in kernel mode (for >> example, whenever they're idle or waiting for I/O). An active process >> may switch back and forward between kernel mode and user mode >> thousands of times a second. > > Thanks for the clarification. > >> Maybe you should describe your problem. > > The application has been working fine for almost 3 years, along with > Apache, going through RELENG upgrade without problem. > > Now I start noticing that Apache hangs (sig 11), A hang is when the system stops reacting. Signal 11 is not a hang: it's a segmentation violation, which means that the program has performed a specific kind of illegal operation. In the case of a program that used to work well, this almost invariably means that you have hardware problems. > 2 options: > > - I added memory in the machine and the meory is causing problems. Yes, this is possible > - I changed my application a little bit and it started eating > other processes. This is less likely. > So I'd like to be sure that my application cannot eat other > processes, so i could eliminate one cause. Don't even think about this at the moment. If you have just installed new memory and these problems occur, try taking it out again and seeing if the problem goes away. Greg -- When replying to this message, please copy the original recipients. If you don't, I may ignore the reply or reply to the original recipients. For more information, see http://www.lemis.com/questions.html See complete headers for address and phone numbers. --N5iGxCIPT7YMRg16 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.3 (FreeBSD) iD8DBQFFNFzSIubykFB6QiMRAgf/AKCuzhRMrv1SkVhZWxGUJdkErzZS5QCfSEP3 mT9qt5Au/h4hsLyyEnI0C9I= =s0Uv -----END PGP SIGNATURE----- --N5iGxCIPT7YMRg16--
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