Messages in this thread | | | Date | Tue, 6 Jun 2006 10:23:29 +0000 (GMT) | From | Holger Kiehl <> | Subject | Question regarding ext3 extents+mballoc+delalloc |
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Hello
Looking at ways to increase write performance on my system using ext3 Andreas Dilger pointed me to delalloc+mballoc+extent patches. Downloaded those from ftp://ftp.clusterfs.com/pub/people/alex/2.6.16.8 and run some benchmark, here some results using bonnie++:
Version 1.03 ------Sequential Output------ --Sequential Input- --Random- -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP 2.6.16.19 16G 59223 91 264155 45 111459 36 57313 99 317944 63 1478 7 58814 92 276803 47 110418 36 57105 99 317534 65 1525 5 58299 92 274523 48 110290 36 56723 99 318839 65 1502 4
And here the results when mounting without extents,mballoc,delalloc option:
Version 1.03 ------Sequential Output------ --Sequential Input- --Random- -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP 2.6.16.19 16G 38621 98 194816 94 87776 49 37921 92 239128 54 1402 5 47000 99 194276 94 89232 49 38628 92 240539 55 1399 5 45873 98 178195 90 89726 50 38482 92 240490 55 1381 4
So using delalloc+mballoc+extent gives an approx. 30% increase in performance.
Using my own benchmark afdbench where many process copy thousands of files around, the results are as follows:
With extents,mballoc,delalloc
5488.36 files per second 14.19 MB/s
Without extents,mballoc,delalloc
4829.84 files per second 12.72 MB/s
The performance increase is approx. 12%.
So the question is, why are these patches not included into the kernel? I did some very extensive testing for several days and could not discover any disadvantage using those patches. I must add that I did not test crashes to see if data is lost. Are there any disadvantages using these patches?
Please CC me since I am not subscribed to the list.
Thanks, Holger --
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