Date: Mon, 29 Nov 2004 04:32:20 -0800 (PST) From: Arne "Wörner" <arne_woerner@yahoo.com> To: freebsd-i386@freebsd.org Subject: RE: i386/74074: hw.ata.wc=0 / but write cache still enabled Message-ID: <20041129123220.76752.qmail@web41204.mail.yahoo.com> In-Reply-To: <20041129113851.270446278@mail.alpha-tierchen.de>
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--- Björn König <bkoenig@cs.tu-berlin.de> wrote:
> Perform a small benchmark, e.g. with /usr/ports/benchmark/bonnie (bonnie -d
> /usr -s <twice as much as your RAM>). Perhaps the write cache is turned off,
> but it's not shown correctly. If your write transfer rates around 10 MB/s
> then the write cache might be disabled. Show the complete result and tell
> also your CPU model.
>
I use an AMD Athlon(tm) XP 2400+ (2000MHz).
Here are bonnie's results:
AFTER my "dd if=/dev/ad1 bs=512k count=1000 of=/dev/null"-trick (somehow this
trick seems to
change the write speed dramatically (factor 5; /opt/tmp is on /dev/ad1))
WITH hw.ata.wc=0:
neo# bonnie -d /opt/tmp -s 1024 -m Athlon2400
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
Athlon24 1024 47464 55.1 46720 24.9 17561 9.7 44685 56.0 43861 26.5 146.4 2.8
WITHOUT the "trick"
AFTER a fresh boot
WITH hw.ata.wc=1:
neo# bonnie -d /opt/tmp -s 1024 -m Athlon2400
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
Athlon24 1024 6540 7.3 47957 23.9 15591 11.6 46357 57.1 44280 23.3 142.4 3.6
AFTER previous test
WITH hw.ata.wc=1:
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
Athlon24 1024 46270 57.7 47708 24.4 17995 9.5 44864 55.5 43965 23.5 150.2 2.2
AFTER fresh boot
WITHOUT trick
WITH hw.ata.wc=0
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
Athlon24 1024 6570 14.4 47726 24.0 15634 13.7 46413 57.1 43569 15.5 155.6 1.2
AFTER previous test
WITH hw.ata.wc=0
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
Athlon24 1024 48619 54.4 46796 37.1 15268 19.7 45892 59.7 44151 16.0 159.8 1.2
-Arne
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