cvs commit: src/usr.sbin/syslogd syslogd.c
rwatson at FreeBSD.org
Fri Mar 31 16:31:11 UTC 2006
On Fri, 31 Mar 2006, Alexander Leidinger wrote:
>>> 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).
I think you'll find the cost of an fstatfs() call is so low that the cost of
setting up monitoring is appreciably similar. I think the right thing to do,
if worried, is to prototype the architecturally simple solution, and then see
if there's a problem. Premature optimization is what happens when you
complicate software in order to solve a performance problem that doesn't
exist, possibly resulting in slower software, and certainly resulting in
harder to maintain software. :-) I'm pretty sure you'll find that the cost
of fstatfs() is basically unmeasurable in this context.
Robert N M Watson
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