Date: Tue, 9 Mar 1999 17:50:01 -0800 (PST) From: Hideaki Okada <hokada@isl.melco.co.jp> To: freebsd-bugs@FreeBSD.org Subject: Re: kern/10398: Tagged queueing makes IBM DCAS-34330 slow Message-ID: <199903100150.RAA56884@freefall.freebsd.org>
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The following reply was made to PR kern/10398; it has been noted by GNATS.
From: Hideaki Okada <hokada@isl.melco.co.jp>
To: "Kenneth D. Merry" <ken@plutotech.com>
Cc: freebsd-gnats-submit@FreeBSD.ORG, hokada@isl.melco.co.jp
Subject: Re: kern/10398: Tagged queueing makes IBM DCAS-34330 slow
Date: Wed, 10 Mar 1999 10:48:21 +0900
Ken,
Thanks for your support.
> So, the first thing to try is your bonnie test above, with write caching
> enabled and with write caching disabled.
> The next thing to try is to change the number of tags on the fly and
> try to determine whether there is a point where performance drops off
> completely.
Here are results of bonnie, measured configurations are:
WCE=1, tags=1, 2, 3, 4, 8, 16, 32, 64
WCE=0, tags=1, 4, 16, 64
-------Sequential Output-------- ---Sequential Input-- --Random--
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
CONFIGURATION
Number of Tags
write cache enabled
NO 100 7222 89.2 6801 21.8 2347 8.5 7330 93.3 7368 14.6 226.5 4.7
2 100 7263 90.3 6357 20.3 2730 9.9 7025 90.5 7321 14.9 209.4 4.6
3 100 7115 88.1 6406 20.8 2289 8.9 7307 93.9 7335 15.0 212.6 4.5
4 100 7281 90.0 6204 20.8 2278 9.1 7267 93.7 7350 15.3 217.6 4.8
8 100 7236 89.7 6007 19.4 2284 8.7 7239 93.1 7374 14.9 213.4 4.5
16 100 6775 83.7 6110 19.5 2283 8.7 7239 93.1 7380 14.8 217.8 4.8
32 100 7265 89.9 4385 13.9 2274 8.7 7302 93.7 7324 14.5 218.9 4.5
64 100 6731 83.3 3038 9.8 2271 8.7 7337 94.6 7356 14.7 213.6 4.4
write cache disabled
NO 100 1638 19.9 1268 3.9 1960 7.1 7377 94.2 7356 14.3 218.4 4.4
4 100 5032 62.0 3559 11.5 2277 8.9 7262 93.6 7374 15.1 216.8 4.6
16 100 5705 70.3 4599 14.6 2255 8.8 7290 93.5 7374 15.1 209.5 4.6
64 100 2847 35.0 2752 8.8 2261 8.6 7360 94.0 7374 14.7 215.3 4.6
Because it is easier to read how configuration affects,
attached results of dd if=/dev/zero of=foo bs=64k count=1000
(WCE=1)
tags bytes/sec
NO 7258435
2 6593304
4 6551596
8 6119427
16 5853919
32 5200000
64 3048527
I hope this mail has enough information for you.
thanks,
Hideaki Okada
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