cvs commit: src/usr.sbin/syslogd syslogd.c
babkin at verizon.net
Fri Mar 31 14:00:33 UTC 2006
>Robert Watson <rwatson at 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.
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