Date: Fri, 20 May 2005 11:57:03 -0700 From: Kris Kennaway <kris@obsecurity.org> To: Dan Nelson <dnelson@allantgroup.com> Cc: Kris Kennaway <kris@obsecurity.org> Subject: Re: panic in recent RELENG_5 tcp code path Message-ID: <20050520185703.GA53904@xor.obsecurity.org> In-Reply-To: <20050520185556.GB51092@dan.emsphone.com> 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> <20050520185556.GB51092@dan.emsphone.com>
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--X1bOJ3K7DJ5YkBrT Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable 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=20 > > > J> words, what does INVARIANTS do concretely, shall I expect a=20 > > > J> performance drop like WITNESS does ? > > >=20 > > > No. The performance loss is _much_ less significant than in WITNESS > > > case. You probably will not notice it. > >=20 > > Actually, INVARIANTS causes about a 10% penalty on wall clock time on > > 5.x and above. >=20 > 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 --X1bOJ3K7DJ5YkBrT Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (FreeBSD) iD8DBQFCjjL+Wry0BWjoQKURAkrZAKD5/pIjyuecvXhCdVHG18YDbPj5dQCgmw8s Hom2U7XJqw3RjvFVfappmkI= =ErMN -----END PGP SIGNATURE----- --X1bOJ3K7DJ5YkBrT--
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