2.4 vs 2.6

[John]

Cef wrote:

>On Mon, 13 Sep 2004 17:24, John wrote:
>  
>
>>2.4 kernels outperform 2.6 at disk I/O on all systems I've tried them on.
>>Knoppix 3.6  2.4 on the Ubuntu box 18.5
>>             2.6                   15.5
>>             2.4 on my SuSE box    30 SuSE manages 29.5
>>             2.6                  <10
>>    
>>
>
>What are the figures measured in? Units please.
>
>What tool/test was used to get these figures?
>
>  
>
>>U Intel BX
>>S Intel 815
>>    
>>
>
>U for Ubuntu and S for SuSE I'm guessing?
>
>  
>
>>The problem I originally noticed it on is a Gigabyte mobo, SiS chipset.
>>I think I reported the same sort of thing on my Acerpower 4400 (Via),
>>but I don't care to reboot that atm to check it. Ditto my server (Also BX).
>>    
>>
>
>Errrgh! SiS. I've had enough bad stuff with SiS to last me a lifetime.
>  
>

<shrug> I thought it might be a SiS issue when I first saw it. Clearly 
though it's not. In fact, disk I/O as measured by hdparm with a 2.4 
kernel is the best of all my systems - -reasomable since it's newest.

Overall my experience with SiS have been fine; I'm just retiring a 
K6-500 system because it's old, uses an AT kbd (so won't plug into my 
KVM), AT power (so won't power down under software control) and 
sufficient replacements are so cheap. It's always performed just fine. 
My one remaining working Pentium also has a SiS chipset. And, I can put 
768 Mbytes of RAM into the K6 box; neither of the Pentium IIIs above 
support that much.

btw These numbers are interesting:
ns:~# hdparm -tT /dev/hda /dev/sd{a,b}

/dev/hda:
 Timing buffer-cache reads:   536 MB in  2.00 seconds = 268.00 MB/sec
 Timing buffered disk reads:   12 MB in  3.45 seconds =   3.48 MB/sec

/dev/sda:
 Timing buffer-cache reads:   528 MB in  2.00 seconds = 264.00 MB/sec
 Timing buffered disk reads:   26 MB in  3.09 seconds =   8.41 MB/sec

/dev/sdb:
 Timing buffer-cache reads:   528 MB in  2.00 seconds = 264.00 MB/sec
 Timing buffered disk reads:   26 MB in  3.09 seconds =   8.41 MB/sec
ns:~# uname -r
2.4.27-1-686
ns:~#
I haven't got to the bottom of what's going on in that box. It's running 
Sarge.