[Bug 660043] Re: ureadahead buffer size seems too small

[Albert Damen]

** Changed in: ureadahead (Ubuntu)
       Status: New => Invalid

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Title:
  ureadahead buffer size seems too small

Status in “ureadahead” package in Ubuntu:
  Invalid

Bug description:
  Binary package hint: ureadahead

  After upgrading to maverick, I noticed boot time was longer than with lucid, about 42s in maverick instead of 30s in lucid.
  From the bootchart it seemed ureadahead was not properly working. It showed continuous hdd activity.
  From the ureadahead changelog I saw buffer size had been decreased to 8MB. Therefore I rebuilt ureadahead with the previous 128MB/num_cpus. That gave a good boot speed again, 28.21s, slightly faster than lucid.
  I also built a version with fixed 8MB buffer, independent of num_cpus. That gives about the same result as 128MB/num_cpus. Was the division by num_cpus intended?
  With the original maverick ureadahead the pack file was about 480kbyte, with 128/num_cpus the pack file was about 1 MB, with 8MB pack file is 993kB.
  Processor is an Intel T7500, dual core.
  File system is ext 4 on lvm on a laptop hdd (320GB, 7200 rpm).

  I also dumped the pack files and counted the number of files (grep bytes on the dump):
  maverick original: 1676 files
  with buffer 128MB/num_cpus: 3413 files
  with buffer 8MB fixed: 3368 files

  ProblemType: Bug
  DistroRelease: Ubuntu 10.10
  Package: ureadahead 0.100.0-8
  ProcVersionSignature: Ubuntu 2.6.35-22.34-generic 2.6.35.4
  Uname: Linux 2.6.35-22-generic x86_64
  Architecture: amd64
  Date: Wed Oct 13 18:06:26 2010
  PackDump: Error: command ['ureadahead', '--dump'] failed with exit code 4: ureadahead:/var/lib/ureadahead/pack: Permission denied
  ProcEnviron:
   PATH=(custom, user)
   LANG=en_US.utf8
   SHELL=/bin/bash
  SourcePackage: ureadahead

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