Re: [CentOS] Strange performance issues under CentOS 5.1
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: FilenameTypeSize UsedPriority /dev/mapper/VolGroup00-LogVol00 partition 4095992 210592 -1 CentOS 5.1: FilenameTypeSize UsedPriority /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 ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Strange performance issues under CentOS 5.1
On Feb 13, 2008 5:35 PM, Masters IT Gmail [EMAIL PROTECTED] wrote: I am having the same problem about performance issue, well perhaps it is because I have slow memory, I have a P4 HT with 256mb DDR 400 and HD 40 gb, today I reinstalled the -OS Centos 5.1 final with gnome. I don´t know if it is okay to have only 4 megs of ram free. Perhaps I need more ram because I am using gnome I ask because is the first time I probe linux in my desktop pc, I note that is acting slow what do you think? There are some ways to free up some memory in order to better adjust my os with a minimum amount of ram like 256mb. This pc is for learning, so I don´t know if it deserves buying more memory but your experience is more than mine. Thanks in advance. George from Uruguay. George, I'm fairly confident your system is swapping and thereby causing the issue, you can check it out with dstat for example. A old 40 GB harddrive is not improving the situation, I'm sure iostat (part of the sysstat RPM package) will tell you by showing a high await value. You need at least 512 MB to run just Gnome in a resonable paste, you may want to consider some lightweight window manager such as xfce4, blackbox etc. - Nicolas ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
RE: [CentOS] Strange performance issues under CentOS 5.1
Masters IT Gmail wrote: I am having the same problem about performance issue, well perhaps it is because I have slow memory, I have a P4 HT with 256mb DDR 400 and HD 40 gb, today I reinstalled the -OS Centos 5.1 final with gnome. I don´t know if it is okay to have only 4 megs of ram free. Perhaps I need more ram because I am using gnome I ask because is the first time I probe linux in my desktop pc, I note that is acting slow what do you think? I think you should have at least double the memory of what you have. Even 512MB is light for a modern GNOME desktop (I recently re-built an older Athlon 1300 w/512MB ram for my mother and 512MB wouldn't get the system responsive enough for me to use on a regular basis, though she was used to slower computers anyways so it was still an improvement). Or don't use gnome, there are plenty of other window managers out there(I'm a fan of Afterstep for example) that provide less things but at the same time use far less resources. Of course if you try to run stuff like firefox, open office etc you'll still run into a memory wall pretty quick. Opera is a good choice for low memory systems. I'm sure there are others as well. nate nate ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
RE: [CentOS] Strange performance issues under CentOS 5.1
Thanks nate! Know I really understand how this Works, okay maybe a little more than yesterday, hehe. So I am going to buy some extra memory in order to keep with my Linux study, thanks for all I really appreciate you help. -Mensaje original- De: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] En nombre de nate Enviado el: Miércoles, 13 de Febrero de 2008 02:54 p.m. Para: centos@centos.org Asunto: RE: [CentOS] Strange performance issues under CentOS 5.1 Masters IT Gmail wrote: I am having the same problem about performance issue, well perhaps it is because I have slow memory, I have a P4 HT with 256mb DDR 400 and HD 40 gb, today I reinstalled the -OS Centos 5.1 final with gnome. I don´t know if it is okay to have only 4 megs of ram free. Perhaps I need more ram because I am using gnome I ask because is the first time I probe linux in my desktop pc, I note that is acting slow what do you think? I think you should have at least double the memory of what you have. Even 512MB is light for a modern GNOME desktop (I recently re-built an older Athlon 1300 w/512MB ram for my mother and 512MB wouldn't get the system responsive enough for me to use on a regular basis, though she was used to slower computers anyways so it was still an improvement). Or don't use gnome, there are plenty of other window managers out there(I'm a fan of Afterstep for example) that provide less things but at the same time use far less resources. Of course if you try to run stuff like firefox, open office etc you'll still run into a memory wall pretty quick. Opera is a good choice for low memory systems. I'm sure there are others as well. nate nate ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Strange performance issues under CentOS 5.1
On Tue, 2008-02-12 at 21:15 -0500, Alfred von Campe wrote: I am still running CentOS 4.6 on our production systems, but I am starting to plan the upgrade to CentOS 5.1. I have one test system running 5.1 that is the exact same hardware configuration as my 4.6 test system. One of our builds runs about 6 times slower on the 5.1 system, even though is uses less overall CPU time. I first suspected something wrong with the disk, but the results from bonnie++ show that the 5.1 system is slightly faster: Version 1.03 --Sequential Output-- --Sequential Input- --Random- -Per Chr- --Block-- -Rewrite- -Per Chr- -- Block-- --Seeks-- MachineSize K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec % CP /sec %CP centos4.6 16G 35933 10 21301 5 46507 6 41.8 0 Version 1.03 --Sequential Output-- --Sequential Input- --Random- -Per Chr- --Block-- -Rewrite- -Per Chr- -- Block-- --Seeks-- MachineSize K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec % CP /sec %CP centos5.1 16G 42015 14 21179 5 49863 4 91.6 0 Then I ran the build with /usr/bin/time --verbose, and here are the results (first 4.6 then 5.1): Command being timed: make User time (seconds): 32.15 System time (seconds): 3.52 Percent of CPU this job got: 99% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:35.88 Command being timed: make User time (seconds): 22.05 System time (seconds): 3.11 Percent of CPU this job got: 11% Elapsed (wall clock) time (h:mm:ss or m:ss): 3:31.35 As you can see from the above, there is a lot of idle time on the 5.1 system. Finally, I ran the build with strace -c, and here are the top ten lines of that output (again, 4.6 first and then 5.1): % time seconds usecs/call callserrors syscall -- --- --- - - 53.81 16.804147 54916 30658 waitpid 34.75 10.853461 82851 131 wait4 5.291.650844 9177706154581 open 1.610.503701 15 34408 read 0.910.283706 15 18607 write 0.600.185894 12 14919 10364 stat64 0.520.163340 10 16495 9079 access 0.470.146933 7 20581 mmap2 % time seconds usecs/call callserrors syscall -- --- --- - - 60.07 15.173924 52687 28858 waitpid 38.509.724412 83831 116 wait4 0.540.135194 7 19199 10705 access 0.360.090850 54 1681 1334 execve 0.270.067686 5 14423 10570 stat64 0.110.027676 1 24832 read 0.090.022339 0155810135765 open 0.030.007617 15948 unlink Any suggestions as to what could possible be causing this? I am fresh out of other ideas to try. Check BIOS settings? For memory, CAS etc. the same? Disk hardware the same and specified identically? Presumming that nothing is found there, install system accounting packages and run some SAR reports. You may see a clue in them. Any tweaks on the old system you forgot to apply on the new? Elevator, buffer flush interval changes, etc? 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. I notice an execve shows on the new one that is not in the old. One says hmmm. What does swapon -s show? Is the system seeing the same amount of memory available or have BIOS settings in one reduced available? 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. Front side bus and memory speeds set the same in BIOS? That's all I can think of that may be even remotely related ATM Alfred snip sig stuff HTH -- Bill ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
