Bug 486417 - [RFE]: Make readahead smarter
Summary: [RFE]: Make readahead smarter
Keywords:
Status: CLOSED RAWHIDE
Alias: None
Product: Fedora
Classification: Fedora
Component: readahead
Version: rawhide
Hardware: All
OS: Linux
low
medium
Target Milestone: ---
Assignee: Harald Hoyer
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2009-02-19 17:20 UTC by David Kovalsky
Modified: 2014-03-31 23:44 UTC (History)
3 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2009-08-13 11:47:20 UTC
Type: ---
Embargoed:


Attachments (Terms of Use)
patch to ignore large files (2.53 KB, patch)
2009-09-26 20:13 UTC, Raphael Geissert
no flags Details | Diff

Description David Kovalsky 2009-02-19 17:20:40 UTC
* Refuse to run readahead on a memory starved system (<512MB)
* Run with low priority (ionice)
* Don't preload database files, which make things slower
  (Full read vs. application seek)
For exaple kmods which read RPM database

Comment 1 Harald Hoyer 2009-02-19 17:23:50 UTC
move datafiles to /var

Comment 2 Harald Hoyer 2009-02-20 09:50:00 UTC
readahead-1.4.8 with ionice, more excluded directories and does not run on memory < 384MB

Comment 3 Raphael Geissert 2009-09-26 20:13:48 UTC
Created attachment 362779 [details]
patch to ignore large files

(In reply to comment #2)
> readahead-1.4.8 with ionice, more excluded directories and does not run on
> memory < 384MB  

Please excuse me for replying to this old report, but why do you think that not running readahead when the machine doesn't have more than 348MBs is "helpful"?
At the Debian package I've reverted that change since it doesn't make sense to me, as the amount of memory required to preload the files is directly dependent on what the system loads and on what the user can actually have running at the same time. On several setups, even when not excluding /var I get ~60 when running
cat /var/lib/readahead/early.sorted | awk '{sum+=$1/1024/1024}END{print sum}'

If I were to place a minimum memory requirement I would say users should at least have 128MB of memory.

In any case, I'm attaching a patch I applied to ignore large files (in part so that there's no need to exclude /var).

Comment 4 Harald Hoyer 2009-10-06 14:23:56 UTC
pushed to upstream git


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