[CentOS] Re: Strange performance issues under CentOS 5.1

[Scott Silva]

on 2/13/2008 5:59 AM Alfred von Campe spake the following:
> On Feb 12, 2008, at 21:57, William L. Maltby wrote:
> 
>> Check BIOS settings? For memory, CAS etc. the same? Disk hardware the
>> same and specified identically?
> 
> Pretty much all the same.  They are standard Lenovo desktops, with a 3.4 
> GHz Core 2 Duo and 3 GB of memory (the BIOS doesn't let the OS address 
> more than 3 GB).
> 
>> Presumming that nothing is found there, install system accounting
>> packages and run some SAR reports. You may see a clue in them.
> 
> I will try that next.
> 
>> Any "tweaks" on the old system you forgot to apply on the new? Elevator,
>> buffer flush interval changes, etc?
> 
> Nope, it's a vanilla kickstart install.  I am using the same scripts 
> (with only slight variations) to build both the 4.x and 5.x systems.  I 
> didn't do anything to "tune" the 4.x systems.  That's one of the things 
> I like about CentOS (and RHEL for that matter): they just work out of 
> the box.  A build (make/gcc) is typically CPU bound.  I don't understand 
> how it can get only 11% of the CPU.  That's unheard of.
> 
>> Any other noticeable things on there that may cause it? Presume the
>> slowdown is caused by a process that you are not looking at. "Hangs"
>> while some other process is waiting or tying up the CPU. Try running
>> top.
> 
> There is nothing else running on the systems at the time.  I have lots 
> of terminal windows open on the 4.x system, but I am ssh'ed into the 5.x 
> system and nobody else is logged in.  If anything, the 4.x system should 
> be slower since there are many more things running on it.
>>
>> I notice an execve shows on the new one that is not in the old. One says
>> "hmmm....".
> 
> The execve is in the other as well, just a few lines further down (i.e., 
> it didn't make the cut when I did the "head strace.log").
> 
>> What does swapon -s show?
> 
> CentOS 4.6:
>     Filename                                Type            Size    
> Used    Priority
>     /dev/mapper/VolGroup00-LogVol00         partition       4095992 
> 210592  -1
> 
> CentOS 5.1:
>     Filename                                Type            Size    
> Used    Priority
>     /dev/mapper/VolGroup00-LogVol00         partition       3047416 
> 120     -1
> 
>> Is the system "seeing" the same amount of memory "available" or have
>> BIOS settings in one reduced available?
> 
> CentOS 4.6:
>     MemTotal:      3113612 kB
>     MemFree:         24868 kB
>     Buffers:         23164 kB
>     Cached:        2428508 kB
>     SwapCached:     136108 kB
>     Active:        1685808 kB
>     Inactive:      1257004 kB
>     HighTotal:     2226560 kB
>     HighFree:         1088 kB
>     LowTotal:       887052 kB
> 
> CentOS 5.1:
>     MemTotal:      3114452 kB
>     MemFree:       2722528 kB
>     Buffers:         84592 kB
>     Cached:         174804 kB
>     SwapCached:          0 kB
>     Active:         187084 kB
>     Inactive:       137220 kB
>     HighTotal:     2226560 kB
>     HighFree:      1972860 kB
>     LowTotal:       887892 kB
> 
>> If all new equipment on the new one, open her up and reseat all
>> connections, PCI cards and mem sticks. Make sure all power connectors
>> are well seated to MB and drives.
> 
> I will double check that.  I may also try to install 4.6 on the HW that 
> is currently running 5.1 and see if there is a problem.  With my 
> kickstart scripts I can have the system up and running in less than 30 
> minutes.  That is probably the best next step to rule out any HW 
> issues.  I'll do that as soon as I get into the office.
> 
>> Front side bus and memory speeds set the same in BIOS?
> 
> Should be.
> 
>> That's all I can think of that may be even remotely related ATM
> 
> Thanks for all the excellent suggestions, Bill.
> 
> Alfred
I didn't see it but did you do a 'uname-a" on both systems to see if one is 
running a PAE kernel?


-- 
MailScanner is like deodorant...
You hope everybody uses it, and
you notice quickly if they don't!!!!

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 250 bytes
Desc: OpenPGP digital signature
URL: <http://lists.centos.org/pipermail/centos/attachments/20080213/44f9c6f3/attachment.sig>