Date: Sat, 22 May 2004 09:36:18 -0600 From: Scott Long <scottl@freebsd.org> To: Kevin Oberman <oberman@es.net> Cc: freebsd-current@freebsd.org Subject: Re: Disk performance under CURRENT Message-ID: <40AF7372.30902@freebsd.org> In-Reply-To: <20040521224729.680285D0A@ptavv.es.net> References: <20040521224729.680285D0A@ptavv.es.net>
next in thread | previous in thread | raw e-mail | index | archive | help
Kevin Oberman wrote: > I just ran test of disk writing performance under V4 (STABLE) and V5 > (CURRENT) and was surprised at the difference. > > The test was simple and not at all rigorous. Just a dd bs=256k > if=/dev/zero of=/dev/ad2. This is about the simplest way of dealing with > a disk. No file system or anything else. Just raw data to the device. > > Under STABLE, I get an average of 25 MB/sec to the disk. Under CURRENT, > it drops to 15 MB/sec. I did this because I had noted that it was now > taking over an hour to backup my system disk (40 GB) when it was only > taking 40 minutes when I was running V4.6. The STABLE system was built > yesterday. The CURRENT system last Sunday. > > Any idea why this is so much slower? It looks to me like it must be in > either geom or the disk driver. Btw, before we run off and dig into performance work here, can you send the output of the following from your test machine: sysctl debug.witness_watch Thanks, Scott
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?40AF7372.30902>