Noting that 2.5 is much slower than 2.4 on disk operations (you *touch*
it when you have not-so-fast machine and use KDE, for example), I've
written a silly test that fwrite/fread a single 100Mb file, char by
char, and timing it I have results that I can't understand very well. Of
course, same machine, same hdparm settings, same processes running
(none, it's a notebook without server processes). I've run these test
several time, the results are always more or less the same (ext2):
2.4.19
read: real 0m15.822s
user 0m15.180s
sys 0m0.270s
write: real 0m12.524s
user 0m11.800s
sys 0m0.690s
2.5.70 (up to -bk14, and -mm6)
read: real 0m20.790s
user 0m14.372s
sys 0m0.949s
write: real 0m13.148s
user 0m11.901s
sys 0m0.665
Writing does not drop, but reading has a 6 seconds difference between
user+sys and real that I can't figure out. And the total difference is
"huge". Actually, using anything that touches the disk (it can be a
trivial "aptitude" loading the cache, or a complex KDE) slows down.
I've run these tests on a HP Omnibook w/Celeron, but I have the same
slow down on a Athlon K7.
Is it anyway "normal", something I should expect upgrading from 2.4 to
2.5/2.6? Or there should be something I should check more accurately?
Bye all.
--
Stefano RIVOIR
> Noting that 2.5 is much slower than 2.4 on disk operations (you *touch*
> it when you have not-so-fast machine and use KDE, for example)
I noticed that KDE 3.1.1 was noticably slower to start on 2.5.69 than 2.4.21-rc1
when I briefly tested it on an Athlon XP 2200+ with 512 MB of RAM.
(Unfortunaly I haven't had much time for 2.5 testing, or any testing actually,
for a few months, but I tested it briefly when I first built this machine,
before it went in to production use. Once all the security issues are addressed
in the 2.5 tree, I intend to start using it on a few production boxes, though).
John.
IDE layer is basically the same in 2.4.21-rc and 2.5.70 (but not in -bk).
If you check 2.4.21-rc against 2.5.70 and results will be similar,
it means its not IDE performance problem, but block layer, VM or FS.
Regards,
--
Bartlomiej
On Tue, 10 Jun 2003, Stefano Rivoir wrote:
> Noting that 2.5 is much slower than 2.4 on disk operations (you *touch*
> it when you have not-so-fast machine and use KDE, for example), I've
> written a silly test that fwrite/fread a single 100Mb file, char by
> char, and timing it I have results that I can't understand very well. Of
> course, same machine, same hdparm settings, same processes running
> (none, it's a notebook without server processes). I've run these test
> several time, the results are always more or less the same (ext2):
fwrite/fread is not a good test for IDE performance.
> 2.4.19
>
> read: real 0m15.822s
> user 0m15.180s
> sys 0m0.270s
>
> write: real 0m12.524s
> user 0m11.800s
> sys 0m0.690s
>
> 2.5.70 (up to -bk14, and -mm6)
>
> read: real 0m20.790s
> user 0m14.372s
> sys 0m0.949s
>
> write: real 0m13.148s
> user 0m11.901s
> sys 0m0.665
>
> Writing does not drop, but reading has a 6 seconds difference between
> user+sys and real that I can't figure out. And the total difference is
> "huge". Actually, using anything that touches the disk (it can be a
> trivial "aptitude" loading the cache, or a complex KDE) slows down.
>
> I've run these tests on a HP Omnibook w/Celeron, but I have the same
> slow down on a Athlon K7.
>
> Is it anyway "normal", something I should expect upgrading from 2.4 to
> 2.5/2.6? Or there should be something I should check more accurately?
>
> Bye all.
>
> --
> Stefano RIVOIR
>
>
>
>
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