Messages in this thread | | | Date | Mon, 19 May 2008 19:47:52 -0700 | From | "Reeve Yang" <> | Subject | kernel 2.6.22 CPU shoot up with same amount of file I/O |
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Hi all,
We recently upgrade kernel from 2.6.17.4 to 2.6.22.15 on our products. In our some test, the disk I/O shot as well as CPU utilization, which starving our some other critical process. For the sake of curiosity, I ran bonnie++ on both kernels, following are the result:
## ###############Linux 2.6.17 #1 SMP Tue May 6 ##################################
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 ##################################
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,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++ ###################################################################################
As you can see, the I/O throughput improves about 10%, but CPU utilization is up to 94% from 35% in new and old kernel respectively for the exact the same test on the exact same hardware system. My mother board is Tyan S5102 and the CPU is IPentium(R) 4 CPU 3.40GHz. I searched on the web, some guys suggest to use "highres=off nohz=off clocksource=acpi-pm" etc., but no help. Has anyone here had similar problem on your system? Is this a problem/bug on 2.6.22 kernel?
I saw a patch from Fengguang Wu on this board(http://lkml.org/lkml/2008/1/15/132). Is this the patch targeting the above issue? I'd appreciate if anyone could help me out.
Thanks. - Reeve
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