Re: Help understanding slow down

Robert M. Stockmann
2004-05-24T01:37:14Z

Hi Phy,

Could you also give the uname -a output of both the 2.4.x and
the 2.6.x kernels ? And also mention which make options you use ? :

make : 1 thread , load is around 1.00
make -j 2 : 2 theads , load is around 2.00
make -j 4 : 4 theads , load is around 4.00

# uname -a (dual-Xeon SMP machine)
Linux jackson.stokkie.net 2.4.23abi #1 SMP Sun Jan 25 03:28:48 CET 2004 i686 unknown unknown GNU/Linux
^^^^

# uname -a (poor PII 400 MHz machine)
Linux tapebox.stokkie.net 2.6.6 #1 Thu May 13 05:48:57 CEST 2004 i686 unknown unknown GNU/Linux
^^^ no SMP

Also , is your Opteron machine rather different as the mainstream Opteron
boards, i.e. are there some exotic drivers used ?

Regards,

Robert

> Just for more clarification, here is a perfect
> example:
>
> 2.6.7-p1:
> 24.86user 51.77system 2:58.87elapsed 42%CPU
> (0avgtext+0avgdata 0maxresident)k
> 0inputs+0outputs (13major+7591686minor)pagefaults
> 0swaps
>
> 2.4.21:
> 28.68user 34.98system 1:12.34elapsed 87%CPU
> (0avgtext+0avgdata 0maxresident)k
> 0inputs+0outputs (5691267major+1130523minor)pagefaults
> 0swaps
>
>
> Both runs on the same machine with the same process
> (making headers).
>
> Could someone give me some pointers/directions on
> where to look.
>
> Thank you for your time.
> Phy
>
> --- Phy Prabab <phyprabab@xxxxxxxxx> wrote:
>> Hello,
>>
>> I need some help understanding what is at issue with
>> the extreme lsow down in build times for a custom
>> executable on different kernel versions. The
>> difference is pretty huge:
>>
>> RH 2.4.20-13-7 : ~1m.10s
>> 2.4.22 : ~1m.40s
>> 2.4.26 : ~2m.15s
>> 2.6.1 : ~3m.40s
>> 2.6.2 : ~4m.00s
>> 2.6.3 : ~4m.00s
>> 2.6.6 : ~3m.15s
>> 2.6.6-mm4 : ~2m.10s
>> 2.6.6-mm5 : ~2m.50s
>> 2.6.7-p1 : ~2m.80s
>> (ran five times on every kernel to get approximate
>> time listed)
>>
>> The question is, how can I get the newer kernels to
>> scream like the older kernels?
>>
>> I have moved all files in question to the local disk
>> to rule out network issues (though the 2.6.x kernels
>> are faster at net access). I have run the make
>> command in debug mode and find no differnce betHz
>> w/8G
>> RAM.
>>
>> Thank you for your assistance.
>> Phy
>>
>> __________________________________
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-
Robert M. Stockmann - RHCE
Network Engineer - UNIX/Linux Specialist
crashrecovery.org stock@stokkie.net