Date: Fri, 20 May 2005 13:55:56 -0500 From: Dan Nelson <dnelson@allantgroup.com> To: Kris Kennaway <kris@obsecurity.org> Cc: freebsd-stable@freebsd.org Subject: Re: panic in recent RELENG_5 tcp code path Message-ID: <20050520185556.GB51092@dan.emsphone.com> In-Reply-To: <20050520183738.GA53549@xor.obsecurity.org> References: <20050515120007.GA777@obiwan.tataz.chchile.org> <20050518155130.H87264@carver.gumbysoft.com> <20050519125639.GK818@obiwan.tataz.chchile.org> <20050520080435.GB26938@cell.sick.ru> <20050520131031.GU818@obiwan.tataz.chchile.org> <20050520131536.GA30219@cell.sick.ru> <20050520183738.GA53549@xor.obsecurity.org>
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In the last episode (May 20), Kris Kennaway said: > On Fri, May 20, 2005 at 05:15:36PM +0400, Gleb Smirnoff wrote: > > On Fri, May 20, 2005 at 03:10:32PM +0200, Jeremie Le Hen wrote: > > J> I'm going to recompile my kernel with INVARIANTS but I wonder in > > J> which order of magniture it will slow my kernel down. In other > > J> words, what does INVARIANTS do concretely, shall I expect a > > J> performance drop like WITNESS does ? > > > > No. The performance loss is _much_ less significant than in WITNESS > > case. You probably will not notice it. > > Actually, INVARIANTS causes about a 10% penalty on wall clock time on > 5.x and above. Which is a lot less of a hit than WITNESS is, to be sure. WITNESS is like walking in mud :) Do you know if INVARIANT_SUPPORT by itself is enough to cause the 10% slowdown? That turns on LOCK_DEBUG, which in turn disables inlining of mutex macros. -- Dan Nelson dnelson@allantgroup.com
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