On Fri, May 20, 2005 at 01:55:56PM -0500, Dan Nelson wrote: > 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.
I haven't benchmarked that, but it would be interesting to know. Kris
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