Bug 575897 - CONFIG_MULTICORE_RAID456 causes excessive cpu load
Summary: CONFIG_MULTICORE_RAID456 causes excessive cpu load
Keywords:
Status: CLOSED DUPLICATE of bug 575402
Alias: None
Product: Fedora
Classification: Fedora
Component: kernel
Version: 12
Hardware: All
OS: Linux
low
medium
Target Milestone: ---
Assignee: Kernel Maintainer List
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2010-03-22 16:33 UTC by Dan Williams
Modified: 2010-04-07 05:17 UTC (History)
7 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2010-04-07 05:17:43 UTC
Type: ---
Embargoed:

Attachments (Terms of Use)

Description Dan Williams 2010-03-22 16:33:26 UTC 
Description of problem:
CONFIG_RAID456_MULTICORE is an experimental feature targeted at developers looking to experiment with parallel processing in md raid.  In some situations it show benefits but in other this option causes excessive cpu load and throughput reduction, it is not ready for production systems.

Version-Release number of selected component (if applicable):
kernel-2.6.32.9-70.fc12 (probably all 2.6.32 fc12 releases)


How reproducible:
Always

Steps to Reproduce:
Issue write traffic to the array.
  
Actual results:
async subsytem launches and excessive number of threads


Expected results:
Normal cpu utilization characteristics of the single-threaded raid5d case.


Additional info:
http://marc.info/?l=linux-raid&m=125909551116881&w=2
Comment 1 Dan Williams 2010-03-24 14:27:58 UTC 
Correction, the name of the option is CONFIG_MULTICORE_RAID456.
Comment 2 Chuck Ebbert 2010-04-07 05:17:43 UTC 

*** This bug has been marked as a duplicate of bug 575402 ***
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