Date: Sun, 22 Apr 2001 13:08:38 -0400 From: Seth <aberrant@superconductor.rush.net> To: Andrew Hesford <ajh3@chmod.ath.cx> Cc: freebsd-questions@freebsd.org Subject: Re: ATA100 read/write perofrmance disparity Message-ID: <20010422130838.B29944@superconductor.rush.net> In-Reply-To: <20010422120120.A26375@cec.wustl.edu>; from ajh3@chmod.ath.cx on Sun, Apr 22, 2001 at 12:01:20PM -0500 References: <20010422114836.A6234@superconductor.rush.net> <20010422110843.A99388@cec.wustl.edu> <20010422124619.A29944@superconductor.rush.net> <20010422120120.A26375@cec.wustl.edu>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sun, Apr 22, 2001 at 12:01:20PM -0500, Andrew Hesford wrote: > During the dd write, your system is being used less than 25% of the > time. This is absolutely horrible. Recall that, for my small-block > write, my CPU was being used >50% of the time, and I had Mozilla > building in the background. This means my CPU usage was much higher. There's nothing else eating up CPU time here. Honestly. I do notice that dd spends a lot of time in the "wdrain" state (when it's not in CPU), according to top(1). I also see brief "bioread" states. I don't know what these states really mean. > Something is definitely wrong. On the I/O writes where you get 6000-7000 > K/sec, I get 9000-13000 K/sec. And mine is a UDMA-4 (UltraATA/66) > controller and drive pair. On the Block I/O, where you get 25000 K/sec, > I get 86000. Hm. This certainly isn't encouraging, although your CPU is much more powerful (and therefore is probably less limiting).. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20010422130838.B29944>