Comment 99 for bug 131094

Though I'm not ubutu user, but I do have the same problem while upgrading vanilla kernel from 2.6.17.4 to 2.6.22.15. Therefore it should not be the ubutu specific problem. Here is bonnie++ test result on old and new kernel respectively. The disk throughput is improved 10% but CPU utilization shoot up to 95% from 34%, for the same amount of I/O. Could someone help to point to any patches, or fixes on this issue?

## ###############Linux 2.6.17 #1 SMP Tue May 6
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Version 1.03c ------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
ib-10-34-68-2 2016M 23989 35 44123 6 16360 1 21823 28 43090 1 172.7 0
                   ------Sequential Create------ --------Random Create--------
                   -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
             files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
                16 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++
ib-10-34-68-2.infoblox.com,2016M,23989,35,44123,6,16360,1,21823,28,43090,1,172.7,0,16,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++

## ###############Linux 2.6.22.15 #1 SMP Tue May 6
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bonnie++ -d /storage -s 2016M -u root
                   -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
ib-10-34-68-2 2016M 26078 94 52117 17 23596 5 27172 86 56402 4 160.2 0
                   ------Sequential Create------ --------Random Create--------
                   -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
             files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
                16 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++
ib-10-34-68-2.infoblox.com,2016M,26078,94,52117,17,23596,5,27172,86,56402,4,160.2,0,16,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++
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