Worked around my performance problem!

First of all I came across this post in the Gentoo forums, which hinted at a Ubuntu bug report. I didn’t think that it would make any difference, but there is no harm in trying. Since I’m running 2.6.25 the configuration changes were not exactly applicable. I came up with these configuration changes compared to my previous setup:

75,81c75,83
< CONFIG_LOG_BUF_SHIFT=15
< # CONFIG_CGROUPS is not set
< CONFIG_GROUP_SCHED=y
< CONFIG_FAIR_GROUP_SCHED=y
< CONFIG_RT_GROUP_SCHED=y
< CONFIG_USER_SCHED=y
< # CONFIG_CGROUP_SCHED is not set
---
> CONFIG_LOG_BUF_SHIFT=17
> CONFIG_CGROUPS=y
> # CONFIG_CGROUP_DEBUG is not set
> CONFIG_CGROUP_NS=y
> CONFIG_CPUSETS=y
> # CONFIG_GROUP_SCHED is not set
> CONFIG_CGROUP_CPUACCT=y
> CONFIG_RESOURCE_COUNTERS=y
> # CONFIG_CGROUP_MEM_RES_CTLR is not set
83a86
> CONFIG_PROC_PID_CPUSET=y
145c149
< CONFIG_DEFAULT_AS=y
---
> # CONFIG_DEFAULT_AS is not set
147c151
< # CONFIG_DEFAULT_CFQ is not set
---
> CONFIG_DEFAULT_CFQ=y
149c153
< CONFIG_DEFAULT_IOSCHED="anticipatory"
---
> CONFIG_DEFAULT_IOSCHED="cfq"
215c219
< CONFIG_NR_CPUS=32
---
> CONFIG_NR_CPUS=8
219,221c223,224
< # CONFIG_PREEMPT_VOLUNTARY is not set
< CONFIG_PREEMPT=y
< # CONFIG_PREEMPT_RCU is not set
---
> CONFIG_PREEMPT_VOLUNTARY=y
> # CONFIG_PREEMPT is not set
259c262
< # CONFIG_HZ_250 is not set
---
> CONFIG_HZ_250=y
261,262c264,265
< CONFIG_HZ_1000=y
< CONFIG_HZ=1000
---
> # CONFIG_HZ_1000 is not set
> CONFIG_HZ=250

The changes for CONFIG_PREEMPT and CONFIG_HZ to VOLUNTARY and 250HZ are probably not really necessary, I made them anyway to be more comparable against Ubuntu. As I expected the changes didn’t really help with my slow Audacity loading, but I kept them anyway because according to the Ubuntu bug report this configuration improved audio output.

Then I came across a video from a talk by Val Henson during Lugradio Live USA about “Storage for Startups”. This gave the idea to the setup, which I’m now using and which, fingers crossed, solved my performance problem. The original problem is probably still there, but at least at the moment I don’t see it.

First of all I decided, that I would use LVM2. That would give me more flexibility should I reach any limits with the chosen setup in the future. Here are my steps, which I performed having booted the Gentoo 2007.0 AMD64 Live CD.

  • Dumped all data onto an external drive.
  • Changed the 360Gb partition into a LVM2 physical volume.
  • Created a volume group system on this physical volume (PE Size = 16 Mb).
  • Created a logical volume with 70Gb for /.
  • Created a logical volume with 145Gb for /home.
  • Created a logical volume with 145Gb intended for storage of multimedia data.
  • Created Ext3 file systems in all logical volumes with dir_index.
  • Restoration of all data.

Here is, what looks like now:

# pvs;vgs;lvs
  PV         VG     Fmt  Attr PSize   PFree
  /dev/sda7  system lvm2 a-   360,22G    0

  VG     #PV #LV #SN Attr   VSize   VFree
  system   1   3   0 wz--n- 360,22G    0

  LV         VG     Attr   LSize   Origin Snap%  Move Log Copy%
  home       system -wi-ao 145,11G
  multimedia system -wi-ao 145,11G
  root       system -wi-ao  70,00G

The big moment came, when I loaded my reference MP3 file into Audacity. Both the MP3 file and the Audacity data directory reside in the home volume in my user directory. And what can I say? Ready after 1m49s, basically the same time I measured running under 32bit Knoppix. I did a couple of other MP3 edits during the day, but I haven’t yet seen any problem with this setup. I hope, that it continues to stay this way.


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This entry was posted on June 01st, 2008 and is filed under Linux / Computing. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response or Trackback from your own site.

 
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