Date: Sat, 03 Oct 1998 23:04:58 -0700 From: Mike Smith <mike@smith.net.au> To: Bruce Evans <bde@zeta.org.au> Cc: tlambert@primenet.com, Don.Lewis@tsc.tdk.com, freebsd-fs@FreeBSD.ORG, freebsd-scsi@FreeBSD.ORG, gibbs@plutotech.com Subject: Re: filesystem safety and SCSI disk write caching Message-ID: <199810040605.XAA02017@dingo.cdrom.com> In-Reply-To: Your message of "Sun, 04 Oct 1998 11:37:22 %2B1000." <199810040137.LAA14507@godzilla.zeta.org.au>
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> >> I think it can be interpreted as showing that the performance hit is
> >> very large. `make world' is mostly cpu-bound, and most of it's i/o's
> >> are reads (60% here). I guess it spends less than 5 minutes of its time
> >> writing (27000 block output operations here). An increase of 5 minutes
> >> is very large.
> >
> >This is without "noatime".
>
> Actually, 27000 is with "noatime" on all file systems, and with "async"
> on all file systems that were written to by my `make world' (/tmp, /var/tmp,
> MAKEOBJDIRPREFIX = /c/obj and DESTDIR = /c/root).
>
> >Every inode read, is written, and every
> >directory inode is written multiple times, and all object files and
> >executables, as well as some generated sources, are written.
>
> Yes, the default configuration may be much slower than mine.
I can definitely back your basic point ('make world' is CPU bound) up.
On a 4-way Xeon system with slow disks we were still able to get down
around 40 minutes.
--
\\ Sometimes you're ahead, \\ Mike Smith
\\ sometimes you're behind. \\ mike@smith.net.au
\\ The race is long, and in the \\ msmith@freebsd.org
\\ end it's only with yourself. \\ msmith@cdrom.com
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