Date: Tue, 17 Mar 2009 11:17:55 -0400 From: Mari Kotlov <mkotlov@gmail.com> To: freebsd-performance@freebsd.org Subject: sysctl with KERN_BOOTTIME option vs. gettimeofday() Message-ID: <3edc36610903170817t7ab70c16tdeed1cb3a99e9a52@mail.gmail.com>
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Hi everyone, I am doing a port of C++ code from Windows to FreeBSD and need to replace function GetTickCount(), which is used mostly for the purposes of obtaining elapsed time (e.g. as a millisecond timer). As I understand it, there are two ways to do that: 1) via sysctl() function with CTL_KERN&KERN_BOOTTIME options and 2) via gettimeofday(). In both case, struct timeval is returned, so I can compute the difference between the two times and get the elapsed time. I am wondering if anyone could tell me performance implications of using sysctl() function call to obtain system boot time vs. gettimeofday(). Is one better than the other? More efficient? Are there advantages or disadvantages to using either of these two methods? Any insight would be appreciated. Thanks very much in advance, Mari.
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