ATA disk performance (ICH2 controller), some tests and comparison with Linux2.6.5

Michael Nottebrock michaelnottebrock at gmx.net
Sat Sep 25 15:57:25 PDT 2004


On Sunday 26 September 2004 00:36, Mauro Triulzi wrote:
> Michael Nottebrock wrote:
> >        also substantially impact system performance.  If you want to
> >        do performance measurement, benchmarking, and optimization,
> >        you'll want to turn them off.  This includes various WITNESS-
> >        related kernel options, INVARIANTS, malloc debugging flags
> >        in userland, and various verbose features in the kernel.  Many
> >        developers choose to disable these features on build machines
> >        to maximize performance.
> >
> >So... did you turn off all those?
>
> Yes of course:
>
> foo# uname -a
> FreeBSD foo.bar.com 6.0-CURRENT FreeBSD 6.0-CURRENT #0: Sat Sep 25
> 17:54:29 CEST 2004
> triulzi at foo.bar.com
> <http://lists.freebsd.org/mailman/listinfo/freebsd-current>:/usr/src/sys/i3
>86/compile/MYKERNEL  i386
>
> source tree actualized and built today, *all debugging options disabled

There's more places than the kernel config to turn off performance killing 
debugging, in particular malloc's options - in CURRENT it defaults to AJ, 
while on releases/stable it defaults to aj (see malloc manpage, paragraph 
TUNING).

-- 
   ,_,   | Michael Nottebrock               | lofi at freebsd.org
 (/^ ^\) | FreeBSD - The Power to Serve     | http://www.freebsd.org
   \u/   | K Desktop Environment on FreeBSD | http://freebsd.kde.org
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