James Bottomley wrote:
Please don't drop the cc lists. There are others who probably have more informed opinions than I do who won't get to comment if they don't see it. On Sun, 2007-10-28 at 17:36 -0700, Anthony Ewell wrote:James Bottomley wrote: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). JamesHi James, The other guy reporting the problemhttp://www.centos.org/modules/newbb/viewtopic.php?topic_id=10659&start=0#forumpost34209is 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/dmesgCalibrating 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/secThat 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/dmesgCalibrating 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/sI 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)? JamesComputer C: backup drive: eSATA hard drive: RAID SATA-150-4 CentOS 4.4, 1:05 hours, approx 52 GB backup file 13,333 kBytes/sec CentOS 5.0, 3:16 hours, approx 43 GB backup file 3,656 kBytes/sec Note: 3.6 times slower Hi James, The above shows the dump speed difference between CentOS 4.4 and CentOS 5. I suspected dump at first, until I noticed everything else was about 3 times slower too, such as Parallels, etc. Open Office 2.3 (linux version) opens about 3 times slower. Are there any tests you know of to shake out who is slowing the works down?Yes, could you do backup write tests without dump in the process (as in just do a straight dd from /dev/zero to the devices in centos 4 and 5). If there's no difference in that, it's some scheduling or filesystem issue with dump, I'd expect.When I get a chance, I am going to run a dump from my CentOS 5 install DVD in rescue mode (linux rescue). This to make sure no high level driver is slowing things down. I will let you know what shows up.James
Hi All,
Did the test from the CentOS5 install DVD in rescue mode:
transfer rate 4422 KB/s, estimated finish 4:10.
No symptom change. RATS!
-T
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