Date: Fri, 31 Mar 2006 16:28:15 +0200 From: Alexander Leidinger <Alexander@Leidinger.net> To: babkin@users.sourceforge.net Cc: Joao Barros <joao.barros@gmail.com>, src-committers@FreeBSD.org, Peter Jeremy <peterjeremy@optushome.com.au>, "Christian S.J. Peron" <csjp@FreeBSD.org>, cvs-all@FreeBSD.org, Robert Watson <rwatson@FreeBSD.org>, cvs-src@FreeBSD.org Subject: Re: Re: cvs commit: src/usr.sbin/syslogd syslogd.c Message-ID: <20060331162815.5qhte5ct4co4o0ww@netchild.homeip.net> In-Reply-To: <2893454.4353801143813632253.JavaMail.root@vms169.mailsrvcs.net> References: <2893454.4353801143813632253.JavaMail.root@vms169.mailsrvcs.net>
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Sergey Babkin <babkin@verizon.net> wrote: > >> Robert Watson <rwatson@FreeBSD.org> wrote: >> >>> The cost to check for free space is the cost of a fstatfs() system >>> call on the file descriptor of the log file. This should be handled >>> without touching the disk, so while it's not a cheap system call >>> compared to, say, getpid(), as it acquires locks and enters VFS, it's >>> a lot cheaper than any disk I/O operation. Optional is good, if only >>> because sometimes people do actually want logging to fill the disk, >>> and that's been the behavior historically :-). >> >> Do you know if a kqueue based solution is cheaper? > > Probably should not matter. Syslog writes data to disk > synchronously, right? So anything not involving a disk > access is negligible in cost compared to the main action > of writing the log entry. Regarding syslogd: yes. Regarding the overal system: maybe. Regarding an overloaded server: every cycle matters. When you can get the same (features, quality, nice design, ...) cheaper, why not choose the cheaper one? I don't ask for premature optimization, I just ask for not bloating something in the first place (if the difference in the amount of work is small). Bye, Alexander. -- http://www.Leidinger.net Alexander @ Leidinger.net: PGP ID = B0063FE7 http://www.FreeBSD.org netchild @ FreeBSD.org : PGP ID = 72077137 If you don't say it, they can't repeat it.
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