Shalom,
If I'm guessing which perf logs you are talking about, the answer is yes. If you set log size to 200 MB, when that limit is reached the file will either be trimmed or a new log file created and perhaps a backup kept.
A trim of a log file normally takes out the oldest data first. It depends on whether you are using sam to do the trim or your own shell script.
Another technique I used was this.
cp logfile
> logfile
That clears it after taking a copy.
SEP
Steven E Protter
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
Twitter: http://twitter.com/hpuxlinux
Founder http://newdatacloud.com