> On Jun 12, 2015, at 4:01 AM, Andriy Gapon <a...@freebsd.org> wrote: > > Author: avg > Date: Fri Jun 12 10:01:24 2015 > New Revision: 284297 > URL: https://svnweb.freebsd.org/changeset/base/284297 > > Log: > several lockstat improvements > > 0. For spin events report time spent spinning, not a loop count. > While loop count is much easier and cheaper to obtain it is hard > to reason about the reported numbers, espcially for adaptive locks > where both spinning and sleeping can happen. > So, it's better to compare apples and apples. >
This causes spinning to be exceptionally more expensive just by having KDTRACE_HOOKS enabled, whether or not Dtrace is actually in use. It makes it undesirable to deploy with Dtrace by default since it impacts performance. Is there a way to make the expensive collection optional, or only enable when dtrace is using the lockstat module? Also have you seen the other recent performance complaint related to this commit? Thanks, Scott _______________________________________________ svn-src-head@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
