Date: Fri, 6 May 2005 13:26:25 -0700 From: Kris Kennaway <kris@obsecurity.org> To: Steve Ames <steve@energistic.com> Cc: Kris Kennaway <kris@obsecurity.org> Subject: Re: Benchmarking mpsafevfs with parallel tarball extraction Message-ID: <20050506202625.GA95077@xor.obsecurity.org> In-Reply-To: <20050506201204.GA12764@energistic.com> References: <20050506183529.GA46411@xor.obsecurity.org> <20050506201204.GA12764@energistic.com>
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--n8g4imXOkfNTN/H1 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, May 06, 2005 at 03:12:04PM -0500, Steve Ames wrote: > On Fri, May 06, 2005 at 11:35:29AM -0700, Kris Kennaway wrote: > > Kernel was built without INVARIANTS and other debugging options, > > without ADAPTIVE_GIANT (which causes about a 200% performance penalty > > on system time in my testing, and has marginal impact on real or user > > time) and with 4BSD scheduler (ULE causes spontaneous reboots on this > > machine). The e4500 uses the esp SCSI controller, which runs > > without Giant. >=20 > I'm rather suprised that ADAPTIVE_GIANT causes so much performance > degradation in your testing. On my, admittedly much more modest system, > using ADAPTIVE_GIANT shaves about 6 minutes off a 'make world'. Haven't > really done any research on why that is. I was just suprised by your > 200% performance penalty. Note: system time, not wall clock time. It's probably because the system is otherwise largely Giant-free (no hardware devices under Giant, only things like ttys and CAM). On systems with more Giant usage in the I/O path you might see a benefit. Kris --n8g4imXOkfNTN/H1 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (FreeBSD) iD8DBQFCe9LxWry0BWjoQKURAjz9AJwLtwR7YKSTx2em1+qbUsZmgqBm2ACfRYlv xgw1Kghp5JSq8lfP9LDDTDA= =2I9Q -----END PGP SIGNATURE----- --n8g4imXOkfNTN/H1--
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