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From Sunitha Kambhampati <skam...@Yngvi.Org>
Subject Re: alligned Vs Non Alligned log writes ..
Date Wed, 08 Dec 2004 19:13:50 GMT
>It would be great if  some one can run this test on other platforms and
> post the results to the list.

Heres what I got by running the test on my T40 laptop (Intel Pentium (M)1.6Ghz,4200 rpm IDE
disk (write cache disabled), 1Gb RAM, Windows 2k, ibm142 )

$java allignWritePerfTest2 temp.dat 1024

ordered by speed gain: max gain seen in case of 64k.   
buff(K)  gain %  Alligned write  NonAlligned 
		 ms		 ms
64 	73.88% 	18.75683594 	32.61523438
128 	44.38% 	35.23632813 	50.87402344
256 	22.58% 	70.88378906 	86.89257813
512 	10.35% 	142.5976563 	157.3544922
4 	7.44% 	16.02929688 	17.22265625
32 	5.14% 	16.72363281 	17.58398438
8 	3.52% 	15.82421875 	16.38085938
16 	0.25% 	15.86230469 	15.90136719
2 	0.06% 	15.68652344 	15.69628906
6 	-0.41% 	16.47851563 	16.41015625
12 	-1.72% 	16.41992188 	16.13671875
1 	-6.42% 	15.82324219 	14.80664063
10 	-6.48% 	17.95605469 	16.79199219

-- we get slowdown for buffers < 4k
-- best gain on 64k ( 73 %)

Sunitha. 


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