I was hunted by this bug to but observed some behaviour that might
help...

I  required a i386 12.10 desktop install for some rebuilds. Therefore I
installed it on a VirtualBox install on my Intel Core i7-2600 CPU @
3.40GHz with 32GB RAM. At first it ran fine, but since I was in a hurry
doing full rebuilds, I assigned more RAM and cores to the VM instance.
Since then I am suffering the same performance degredation.

At first I thought it just had to do with VirtualBox, so I installed the
12.10 i386 desktop natively on a build machine (Intel Core i5-2300 CPU @
2.80GHz) with 16 GB RAM). After installation it ran fine for a while but
then it also began to behave weird after I ran apt-get upgrade this
morning.

Since it ran initially fine on the VirtualBox instance, I recalled I
changed the config. After restoring the settings to to what I think it
used to be, all was fine.

I have measured performance on my VirtualBox instance, varying ONLY the
amount of assigned RAM. All other settings have been kept constant. I
used time(1) to measure performance of 'sudo apt-get update'. I took 3
measurements, the times are below.

I think it's safe to assume that the amount of RAM is of importance for
this bug. I have not been able to test with a 64-bit kernel but it might
not be reproducible with that.

Please let me know if you require additional information about one of my
systems.

HTH, Mark


Base Memory: 16384 MB
        Reading package lists... 42% <- aborted at this point
        real    9m42.187s
        user    0m7.952s
        sys     0m7.548s

Base Memory: 15360 MB
        real    0m44.337s
        user    0m2.556s
        sys     0m1.096s

Base Memory: 12288 MB
        real    0m10.399s
        user    0m1.192s
        sys     0m0.456s

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https://bugs.launchpad.net/bugs/1107150

Title:
  B75 Chipset I/O Problems

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