Re: slow after upgrade to CentOS 5 (RHEL5)

[James Bottomley <James.Bottomley@SteelEye.com>]

On Sat, 2007-10-27 at 13:21 -0700, Anthony Ewell wrote:
> James Bottomley wrote:
> > On Wed, 2007-10-24 at 18:04 -0700, Anthony Ewell wrote:
> >> Hi All,
> >>
> >>     If you all would not mind a post from the general
> >> public Linux user, after doing a complete disk wipe
> >> of CentOS 4 and installing CentOS5, my system is preceived
> >> to be 3 times slower.
> >>
> >>      To troubleshooting this, I made a post on CentOS's
> >> bugzilla:  http://bugs.centos.org/view.php?id=2382
> >>
> >>      Would some of the experts on this group mind
> >> looking at the bug to evaluate the possibility
> >> that it is being caused by the underlying scsi
> >> driver?   The post contains a dmesg from "Computer C".
> >> (Yes, I am getting a bit desperate.)
> > 
> > There's still too little information in the bug report to tell much of
> > anything.  The dmesg doesn't indicate any anomaly with the megaraid
> > (although the LSI people might be able to tell better).  However, it
> > also doesn't contain a trace of the tape drive.
> > 
> > Best guess would be a slow down in the megaraid driver.  Can you try
> > doing a speed test on it?  (hdparm -t should suffice).
> > 
> > James
> 
> 
> Hi James,
> 
> The other guy reporting the problem
>  
> http://www.centos.org/modules/newbb/viewtopic.php?topic_id=10659&start=0#forumpost34209
> is not using a MegaRAID card.  He is using 3ware9508 Raid Controllers.
> He is also using a different processor (amd vs xeon) and a different
> chipset (Intel Greenwood vs nVidia)
> 
> I also spoke to Neela Kolli (Mega RAID maintainer) and he said he'd
> never heard of the problem.  Here are some tests (including dhparm)
> that I sent to Neela (he never wrote back).
> 
> I have also checked with Stellen over at the "dump"
> list and he has not seen the problem (yet).
> 
> The problem occurs when backing up to a two different types
> of tape drives and to an eSata drive.
> 
> When I am running a "dump" on computer C, gnome-system-monitor
> shows my two cores running at only about 10 to 20% and
> switching back and forth (one at 0% the other at 20% for
> about 5 seconds, then switching positions)
> 
> On Computer C (Cent OS 5), when typing in Word Pro (a windows word 
> processor) in Parallels, I can watch myself type.  Computer B
> (CentOS 4.4, now 4.5) has the same version of Parallels
> installed on it (Parallels-2.2.2112-lin.i386) that computer C
> (CentOS 5) has. The perceived speed difference is about a factor
> of three (you can not watch yourself type).
> 
> All the "Low Level" test I run seem to come out the same between
> Cent OS 4.4 and 5.  Very frustrating!  It is almost like some
> system monitor component is looking at everything and
> slowing things down.  If this was Windows, I'd go straight
> to the Anti Virus as the culprit.  (Does SE Linux do such
> things?)
> 
> Are there any performance tests I can run for you?
> 
> Thank you for letting me ramble, this problem is
> really frustrating.  I am afraid to any additional CentOS5
> server out there and CentOS 4.x is so terribly out of
> date.
> 
> -T
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Tests I sent to Neela:
> 
> CentOS 5 (2.6.18-8.1.8.el5, Sata150-4):
> 
> #grep -i bogomips /var/log/dmesg
> Calibrating delay using timer specific routine.. 4001.91 BogoMIPS 
> (lpj=2000959)
> Calibrating delay using timer specific routine.. 3999.58 BogoMIPS 
> (lpj=1999791)
> Total of 2 processors activated (8001.50 BogoMIPS).
> 
> 
> #/sbin/hdparm -t /dev/sda
> /dev/sda:
>   Timing buffered disk reads:  236 MB in  3.01 seconds =  78.53 MB/sec
> 
> 
> #/sbin/hdparm -t /dev/sdb
> /dev/sdb:
>   Timing buffered disk reads:  182 MB in  3.01 seconds =  60.37 MB/sec
> 
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> CentOS 4.4 (linux rescue 2.6.9-42.EL, IDE):
> 
> #cat /proc/cpuinfo
> bogomips	: 4002.92
> 
> #/sbin/hdparm -t /dev/sda
> /dev/sda:
>   Timing buffered disk reads:  216 MB in  3.01 seconds =  71.87 MB/sec
> 
> #/sbin/hdparm -t /dev/sdb
> /dev/sdb:
>   Timing buffered disk reads:  184 MB in  3.01 seconds =  61.18 MB/sec

That pretty much shows, if anything, that transfer speed improved
from .9 to .18.

> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> CentOS 5 (2.6.18-8.1.3.el5, Sata300-4):
> #grep -i bogomips /var/log/dmesg
> Calibrating delay using timer specific routine.. 4001.92 BogoMIPS 
> (lpj=2000960)
> Calibrating delay using timer specific routine.. 3999.58 BogoMIPS 
> (lpj=1999794)
> Total of 2 processors activated (8001.50 BogoMIPS).
> 
> #/sbin/hdparm -t /dev/sda
> /dev/sda:
>   Timing buffered disk reads:  214 MB in  3.02 seconds =  70.86 MB/sec
> 
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> CentOS 5  (2.6.18-10.1.3.el5, Sata300-4):
> 
> eSata:  dump -0a -z -f /dev/nul winxp.hdd
>    DUMP: Volume 1 took 0:04:04
>    DUMP: Volume 1 transfer rate: 4247 kB/s
>    DUMP: Volume 1 1567020kB uncompressed, 1036385kB compressed, 1.513:1
> 
> eSata:  dump -0a -f /dev/nul winxp.hdd  (no compression)
>    DUMP: Volume 1 1036420 blocks (1012.13MB)
>    DUMP: Volume 1 took 0:02:09
>    DUMP: Volume 1 transfer rate: 8034 kB/s
> 
> 
> 150-4:  dump -0a -z -f /dev/nul winxp.hdd
>    DUMP: Volume 1 took 0:04:05
>    DUMP: Volume 1 transfer rate: 4230 kB/s
>    DUMP: Volume 1 1573150kB uncompressed, 1036383kB compressed, 1.518:1
> 
> 150-4:  dump -0a -f /dev/nul winxp.hdd  (no compression)
>    DUMP: Volume 1 1036420 blocks (1012.13MB)
>    DUMP: Volume 1 took 0:02:05
>    DUMP: Volume 1 transfer rate: 8291 kB/s

I think this is beginning to point to problems with dump.  What are the
corresponding figures for dump under 2.6.9 (or are the two sets of
figures centos5 followed by centos4)?

James