Re: [CentOS] DVI + VGA?
As far as i know you don't need to change anything in your xorg.conf. if you have any horizontal / vertical sync settings (Hz) in your conf you can remove them. DVI is digital and don't need them. correct me please if Im wrong. Marco MHR wrote: I have an LCD monitor with both VGA and DVI connectors on it, and a video card to match (both connectors). If I want to switch from the VGA (currently in use) to the DVI, do I need to do anything special other than switch wires? I didn't see anything in google that was helpful (though I may not have used a smashing search...). Thanks. mhr ___ 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
[CentOS] Questions on cpu frequency scaling AMD vs. Intel
I've been playing and comparing frequency scaling between AMD and Intel CPUs yesterday and there seem to be great differences between AMD and Intel and some gotchas. This is all on CentOS 5.2 with latest Xen kernels (which are supposed to be powersaving-enabled since 5.2). AMD: It seems once I get the AMD CPU to use the ondemand governor it works very well and very efficiently. But this is not set by default, one has to set ondemand explicitely in /etc/sysconfig/cpuspeed and run cpuspeed on bootup. Otherwise it just knows about userspace and performance and defaults to performance. Intel: On the other side ondemand is on for Intel CPUs automatically, but it doesn't seem to work. No matter if I run cpuspeed or not the current frequency is shown as 200. This is the scaling_min_freq for both CPUs I checked. The scaling_max_freq is 2.333/2.5. One is a Xeon Dual Core, one a Xeon Quad Core. With not seem to work for Intel I mean it doesn't act on demand as it should. I tested by gzipping and gunzipping a 4 GB image file. I used top to observe CPU utilization. With a dual core the idle percentage stays around 50% for a while and only goes below this threshold near the end of the operation. I deduce that means that gzip can make use of only one core and only when it comes to writing to disk or using other external tools it can utilize more CPU power because that task is taken over to the other core. Same observation with quad core (and 75%). There is no difference between AMD and Intel in this respect, but the task seems to run a bit more efficiently on an AMD CPU - e.g. it is able to max out idle at 0% at least for short periods while this is almost impossible to observe with the Intel CPUs. The timing also shows that the AMD is the fastest one. (The AMD, a very new low voltage X2, also runs at 2500 max.) My question: why don't the Intel CPUs don't scale up on demand? Could there be a bug in the driver that it measures overall utilization (which is at 50% most of the time) and not single core utilization, thus never reaching the threshold for scaling up? up_threshold is at 80 for both CPUs. (cat /sys/devices/system/cpu/cpu0/cpufreq/ondemand/up_threshold) I have a somewhat related question. That very new AMD CPU mentioned above was not recognized by CentOS 5.2 and the current frequency was shown as 80 (instead of 250), although it was running in full speed. The latest kernel corrected this. It's still unknown, but the frequency is now calculated correctly and thus frequency scaling works now (it didn't work when it was miscalculating at 80). On the other hand, I have an older low-voltage AMD CPU (probably about 2 years on the market) that is recognized as X2 3800+ but frequency scaling fails because it miscalculates the current speed to 800 MHz as well. Is there anything I can do about that? Where could I check whether this CPU should be supported in full and frequency scaling working? (I'm not sure, but I think it may have actually worked when it was running in a different motherboard.) Kai -- Kai Schätzl, Berlin, Germany Get your web at Conactive Internet Services: http://www.conactive.com ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Isolinux disk error 20; AX=4280, drive EF
Thanks Dag. I'm wondering if I'll have a similar problem with a multi CD ROM set instead of the one DVD? The system loaded RHEL WS 3, update 4 Taroon just fine from CD's. I'm leaning towards the same issue you mention. The large DVD ISO image is not recognizable by the system. At the time the system was put together, there were no DVD ISO images, just CD. The DVD ROM drive works just fine. Plays movies etc. The dual boot, Win 2000 Pro / Red Hat system would not mount the DVD however. Win XP, separate newer machine with a Samsung DVD reader mounts disk just fine and reads contents before freezing. It has a Plextor 712SA DVD RW unit. The older system has an HP DVD writer 300i. I don't recall who made the other DVD ROM. What do you think, could a CD ROM set solve the boot problem? Dag Wieers wrote: On Sat, 2 Aug 2008, Ed Westphal wrote: Lanny Marcus wrote: On Sat, Aug 2, 2008 at 1:37 PM, Ed Westphal [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] wrote: I thought I'd be clever and buy a DVD for 5.2 from LinuxOnline.biz. Well, just got around to trying it with the above results. Does the error mean I have a 'bad' DVD disk image? Please advise. Thanks. Boot from the DVD and at the boot prompt, type linux mediacheck (without the quote marks). That will check the DVD, to see if it checks out OK. That said, a few days ago, I installed from a DVD that did not pass linux mediacheck and that box is running OK. YMMV. Thanks Larry. Not even getting to a boot prompt. First time, it was saying: 'Press any key to try again'. - gives same results. I've been Googling the above. It seems that there are some incompatibilities that others have reported with Isolinux? I'm wondering if others here have seen the problem here? I know about the checksum error thing. I've done other installs from CD's without a problem. Thought a DVD would be a better install medium. Perhaps with my Intel D875PBZ motherboard, there is a conflict loading ISO images? Don't know. Haven't found any workarounds if that is indeed the case. I have the latest Intel bios. Is there one install medium provider that most prefer? To be sure to get good disks. I'd prefer getting a disk(s) from someone rather than trying to burn my own. Thoughts, advice appreciated. Thanks. I suspect it is not a medium problem but rather an incompatibility (or bug) with isolinux and your DVD drive. So most likely the same would happen with any other provided media (or own-written media). I would suggest comparing the MD5 or SHA1 from the DVD with the online provided checksum to make sure the image is intact. But the chances are really slim that the isolinux bootloader got corrupted, so I doubt it will make a difference... ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Questions on cpu frequency scaling AMD vs. Intel
Kai Schaetzl wrote: I've been playing and comparing frequency scaling between AMD and Intel CPUs yesterday and there seem to be great differences between AMD and Intel and some gotchas. This is all on CentOS 5.2 with latest Xen kernels (which are supposed to be powersaving-enabled since 5.2). I was looking at cpu frequency scaling a week or two ago on an Intel Q6600 quad core cpu. Rather than repeat myself, there are some numbers in this thread (post #6 amongst others): http://www.centos.org/modules/newbb/viewtopic.php?topic_id=15484forum=37 Bottom line - the power saving between having frequency scaling enabled or not was surprisingly small (only 2-3W). It would appear that these processors are already fairly efficient at idle and scaling down the frequency adds little to the overall savings that may be obtained. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Questions on cpu frequency scaling AMD vs. Intel
Kai Schaetzl wrote on Sun, 03 Aug 2008 14:31:19 +0200: I have a somewhat related question. That very new AMD CPU mentioned above was not recognized by CentOS 5.2 and the current frequency was shown as 80 (instead of 250), although it was running in full speed. The latest kernel corrected this. Actually, not the latest kernel. The CentOS xen boot (hypervisor) kernel /xen.gz-2.6.18-92.1.6.el5 (and maybe earlier) ones calculates the frequency correct, the Xen 3.2 boot kernel (xen.gz-3.2) from the Xen 3.2 package offered at xen.org does not. Might there be a kernel parameter or other measure that could correct this? (I don't want to recompile any kernels.) I wondered if it also the source of the inability to scale up on demand with the Intel CPUs and the 200 reported is actually wrong. But there is no change between the two boot kernels. Kai -- Kai Schätzl, Berlin, Germany Get your web at Conactive Internet Services: http://www.conactive.com ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Questions on cpu frequency scaling AMD vs. Intel
Ned Slider wrote on Sun, 03 Aug 2008 15:09:39 +0100: http://www.centos.org/modules/newbb/viewtopic.php?topic_id=15484forum=37 Thanks for the URL, see below! Bottom line - the power saving between having frequency scaling enabled or not was surprisingly small (only 2-3W). It would appear that these processors are already fairly efficient at idle and scaling down the frequency adds little to the overall savings that may be obtained. I disagree about the reason. I think they are actually not so efficient. At least not if I compare to a low-voltage CPU. 105 W is a lot, latest AMD quad core low-voltage are at 50W. Did you check core temperature in the two scaling states? It makes a huge difference for me on the AMD (which is allowed to drop from 2500 to 1000). It drops from an already low value (30 and 22 Celsius) by more than 10 degrees. The second core always shows the lowest temperature (puzzle?) and it goes down to 6-8 (!) Celsius in idle state with 1000.) I think this will also result on some more substantial savings in Watt consumption. Even, if not, a substantially lower temperature like this is good for a long life of all parts, anyway. I read that thread and am puzzled by acpi-cpufreq being loaded on your machine. If I modprobe it I get an error device busy. Which makes sense to me as cpufreq_ondemand (which loaded automatically) should have already taken over. I see that behavior on all machines, no matter if Intel or AMD. From my research yesterday it also looks like use of acpi-cpufreq is somewhat older and should not be necessary at all for newer CPUs. So, it should be cpufreq_ondemand alone that does the scaling on your machine. Can you confirm that? I also wonder if your machine actually scales up. You listed the output in low/idle state. As I wrote I get the same, just at another level (they probably think Xeon's will be active all the time, anyway, so they allow them to drop not so much). Did you check that the frequency actually goes up to 2400 under load? Kai -- Kai Schätzl, Berlin, Germany Get your web at Conactive Internet Services: http://www.conactive.com ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Questions on cpu frequency scaling AMD vs. Intel
Kai Schaetzl wrote: Ned Slider wrote on Sun, 03 Aug 2008 15:09:39 +0100: http://www.centos.org/modules/newbb/viewtopic.php?topic_id=15484forum=37 Thanks for the URL, see below! Bottom line - the power saving between having frequency scaling enabled or not was surprisingly small (only 2-3W). It would appear that these processors are already fairly efficient at idle and scaling down the frequency adds little to the overall savings that may be obtained. I disagree about the reason. I think they are actually not so efficient. At least not if I compare to a low-voltage CPU. 105 W is a lot, latest AMD quad core low-voltage are at 50W. Did you check core temperature in the two scaling states? It makes a huge difference for me on the AMD (which is allowed to drop from 2500 to 1000). It drops from an already low value (30 and 22 Celsius) by more than 10 degrees. The second core always shows the lowest temperature (puzzle?) and it goes down to 6-8 (!) Celsius in idle state with 1000.) I think this will also result on some more substantial savings in Watt consumption. Even, if not, a substantially lower temperature like this is good for a long life of all parts, anyway. I see no difference on temps reported by coretemp for cpuspeed enabled/disabled. I *do* see a huge drop in temps between load and idle regardless of cpuspeed. I read that thread and am puzzled by acpi-cpufreq being loaded on your machine. If I modprobe it I get an error device busy. Which makes sense to me as cpufreq_ondemand (which loaded automatically) should have already taken over. I see that behavior on all machines, no matter if Intel or AMD. From my research yesterday it also looks like use of acpi-cpufreq is somewhat older and should not be necessary at all for newer CPUs. So, it should be cpufreq_ondemand alone that does the scaling on your machine. Can you confirm that? I'm not sure of the function of acpi-cpufreq. I do know that it doesn't scale back *without* cpufreq_ondemand (cpuspeed). acpi-cpufreq was autoloaded in response to enabling C1E and EIST features in the BIOS (which one is responsible I don't know as I enabled both together). I also wonder if your machine actually scales up. You listed the output in low/idle state. As I wrote I get the same, just at another level (they probably think Xeon's will be active all the time, anyway, so they allow them to drop not so much). Did you check that the frequency actually goes up to 2400 under load? Yes, the frequency does scale up under load. I tested by launching a scientific app that loads all 4 cores at 100%. As fast as I could manually start the app and check the freq, it reported at 2.4GHz. I don't know at what point or under what load it will scale back up, and if scaling is done on a core by core basis, but it does scale back up under full load. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Isolinux disk error 20; AX=4280, drive EF
On Sun, 2008-08-03 at 08:41 -0400, Ed Westphal wrote: Thanks Dag. I'm wondering if I'll have a similar problem with a multi CD snip mention. The large DVD ISO image is not recognizable by the system. At the time the system was put together, there were no DVD ISO images, just CD. The DVD ROM drive works just fine. Plays movies etc. The dual boot, snip Possible BIOS upgrade available? -- Bill ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Isolinux disk error 20; AX=4280, drive EF
Hello William; Are you thinking BIOS update for the motherboard or for the DVD drive, or both? The motherboard has Intel's latest and greatest. The DVD drive I'm not so sure of. It's been awhile since I looked at it's status vis-a-vis bios versions. I've not found bios updaters under Linux. Windows, yes; Linux no. I could remove the drive, put it into the XP box and check it's version that way? Don't you think it may be easier to try the CD set instead? They're about $7.95. The DVD was $4.95 with $5 shipping. RHEL 3 installed easily that way, back in the day. It took 9 CD's at the time. CentOS comes on 6. What do you think? I thought it would be easier to use a single DVD, not envisioning it might be a problem. Dumb me. William L. Maltby wrote: On Sun, 2008-08-03 at 08:41 -0400, Ed Westphal wrote: Thanks Dag. I'm wondering if I'll have a similar problem with a multi CD snip mention. The large DVD ISO image is not recognizable by the system. At the time the system was put together, there were no DVD ISO images, just CD. The DVD ROM drive works just fine. Plays movies etc. The dual boot, snip Possible BIOS upgrade available? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Questions on cpu frequency scaling AMD vs. Intel
Kai Schaetzl wrote on Sun, 03 Aug 2008 16:31:19 +0200: Actually, not the latest kernel. The CentOS xen boot (hypervisor) kernel /xen.gz-2.6.18-92.1.6.el5 (and maybe earlier) ones calculates the frequency correct, the Xen 3.2 boot kernel (xen.gz-3.2) from the Xen 3.2 package offered at xen.org does not. Might there be a kernel parameter or other measure that could correct this? After some more research I have found the correct incantation for this. The CentOS/RH kernels seem to have this enabled by default, the kernels from xen.org have to be enabled with a command-line option to the hypervisor- kernel (not the CentOS kernel). kernel /xen.gz-3.2 cpufreq=dom0-kernel I'm getting now correct readings of the frequencies. And scaling up on demand works. At least in dom0. I'm not so sure if it works for domUs as well. A quick test showed no ondemand scaling in dom0 when running a cpu-intensive task in a domU. Anyone has more experience with this? Kai -- Kai Schätzl, Berlin, Germany Get your web at Conactive Internet Services: http://www.conactive.com ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Questions on cpu frequency scaling AMD vs. Intel
Kai Schaetzl wrote on Sun, 03 Aug 2008 17:59:49 +0200: 5 minutes later: oh, yes, it does! Now I got it to 0% idle and current frequency jumped to 2333000 (although current scaling frequency was still shown at 200, on AMDs both figures rise).Looks like a clear bug in the centrino kernel module to me. It scales only up if the overall threshold is reached Setting the threshold in sysconfig/cpuspeed from 80 to 50 down makes it work, e.g. a single gzip task filling one CPU will be able to scale the frequency up. Kai -- Kai Schätzl, Berlin, Germany Get your web at Conactive Internet Services: http://www.conactive.com ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Isolinux disk error 20; AX=4280, drive EF
On Sun, 2008-08-03 at 12:50 -0400, Ed Westphal wrote: Hello William; Are you thinking BIOS update for the motherboard or for the DVD drive, or both? The motherboard has Intel's latest and greatest. The Both. On CD and DVD drives, I've always checked for updated BIOSs. DVD drive I'm not so sure of. It's been awhile since I looked at it's status vis-a-vis bios versions. I've not found bios updaters under Linux. Windows, yes; Linux no. I could remove the drive, put it into I use one of the free DOS versions on a floppy to do it. They say Windows because most of the great unwashed masses don't realize that Windows is still DOS based. The rest is marketing glitz and glimmer from MS with the real value provided by third party folks - drivers, etc. the XP box and check it's version that way? Don't you think it may be easier to try the CD set instead? They're about $7.95. The DVD was Sure. $4.95 with $5 shipping. RHEL 3 installed easily that way, back in the day. It took 9 CD's at the time. CentOS comes on 6. What do you think? I thought it would be easier to use a single DVD, not envisioning it might be a problem. Dumb me. Well, my 5.2 is on a box I built a couple years ago, EPOX 8KRAIPRO with a LITE-ON DVDRW SHM-165P6S that's about 1.5 years old (IIRC). I burned the DVD and installed from it w/o problem though. I would think newer equipment should have no problem if installation, drive and media are good. snip -- Bill ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Questions on cpu frequency scaling AMD vs. Intel
On Sunday, August 03, 2008 at 8:31 AM, Kai Schaetzl wrote: ...I have an older low-voltage AMD CPU (probably about 2 years on the market) that is recognized as X2 3800+ but frequency scaling fails because it miscalculates the current speed to 800 MHz as well. Is there anything I can do about that? Where could I check whether this CPU should be supported in full and frequency scaling working? The cpuspeed changelog may be relevant: [quote] * Thu Mar 06 2008 Jarod Wilson [EMAIL PROTECTED] - Disable freq scaling by default on AMD rev F and earlier cpus when running xen, due to clock instability (#435321) [/quote] I didn't look up your cpu, but I think it's a revision F. Also, thanks for the /etc/sysconfig/cpuspeed ondemand tip. It seemed counterintuitive to explicitly specify the so-called default governor value (i.e., empty defaults to ondemand), but doing so did the trick under xen for my revision G AMD processor. Steve ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] 64bit vs 32bit
nate wrote: ... Sample memory usage(32-bit): root 4059 0.0 0.2 11616 4532 ?S04:02 0:01 /usr/sbin/snmpd -Lsd -Lf /dev/null -p /var/run/snmpd.pid -a ... 64-bit: root 2792 0.0 0.0 88028 5700 ?S04:02 0:02 /usr/sbin/snmpd -Lsd -Lf /dev/null -p /var/run/snmpd.pid -a ... snmpd - from 11M to 88M That's the virtual size, not the real size: 4532 vs. 5700. Mogens -- Mogens Kjaer, Carlsberg A/S, Computer Department Gamle Carlsberg Vej 10, DK-2500 Valby, Denmark Phone: +45 33 27 53 25, Fax: +45 33 27 47 08 Email: [EMAIL PROTECTED] Homepage: http://www.crc.dk ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
