Date: Fri, 20 Sep 1996 21:11:37 -0700 From: "Michael L. VanLoon -- HeadCandy.com" <michaelv@MindBender.serv.net> To: asami@freebsd.org (Satoshi Asami) Cc: freebsd-scsi@freebsd.org, freebsd-current@freebsd.org, freebsd-isp@freebsd.org Subject: Re: Streamlogic RAID array benchmarks Message-ID: <199609210411.VAA20862@MindBender.serv.net> In-Reply-To: Your message of Fri, 20 Sep 96 18:43:44 -0700. <199609210143.SAA13100@silvia.HIP.Berkeley.EDU>
next in thread | previous in thread | raw e-mail | index | archive | help
> * >Just FYI, we've seen close to 30MB/s with ccd (no mirroring). You
> * >need two 2940?W's (or one 3940?W) and at least four disks though.
> *
> * Just for our edification, what kind of CPU did you use?
> *
> * Also For Everyones' Information, you won't get close to that on a real
> * filesystem unless you use a Pentium or better.
>Yeah, it's a P5 (133MHz). We got pretty much the same result with the
>P6 (200MHz) too (which is kinda surprising, given that their memory
>system is so much slower).
How is that surprising? The SCSI controller lives on the other side
of the bus, and does the bus-mastering irrespective of the CPU. The
CPU does not do bcopies for bus-mastering SCSI transfers.
The problems with the 486 is that its slowness causes too great a
latency between when work becomes available, and when it has something
ready to keep the disk subsystem working, causing less than 100%
efficiency. If all have a (working) PCI bus, what happens on the SCSI
controller side should not be affected by the CPU, except for how busy
the CPU can keep the SCSI controller.
-----------------------------------------------------------------------------
Michael L. VanLoon michaelv@MindBender.serv.net
--< Free your mind and your machine -- NetBSD free un*x >--
NetBSD working ports: 386+PC, Mac 68k, Amiga, Atari 68k, HP300, Sun3,
Sun4/4c/4m, DEC MIPS, DEC Alpha, PC532, VAX, MVME68k, arm32...
NetBSD ports in progress: PICA, others...
-----------------------------------------------------------------------------
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199609210411.VAA20862>