Feature changed by: Stephan Kleine (bitshuffler) Feature #305694, revision 27 Title: Separate Desktop / Server Kernels openSUSE-11.2: New Priority Requester: Important Requested by: Dean Hilkewich (deanjo13) Description: It seems to me that the current default kernels are somewhat hurting openSUSE's performance perception. Current kernel configs are OK but are not very well suited for desktop usage. In the future I would like to see a kernel package that is optimized for desktop usage. Current timer settings and no preemption really (sometimes drastically) hurts openGL performance and applications such as wine and causes alot of issues such as audio studdering. It would be nice to see a separate desktop performance kernel package with options such as Preemption model set to Preemptable Kenel (low-latency Desktop) and Timer Frequency Set to 1000 Hz, HPET support, Tickless System, disable optimize for size, disable Control Group support and disable Group CPU scheduler. You could also disable items and modules that are extremely rare in a desktop environment such as ATM support, Infiniband etc etc as these are not typically used in a desktop scenario which would be a large majority of openSUSE users. Further performance enhancements would also be done through out the system aimed at desktop use as well such as disabling barriers (even making it a simple checkmark option in the partitioner). Such optimizations for desktop usage can overcome openSUSE's reputation as being slower then the other mainstream distro's. The kernel settings alone can make up to a 30-40% increase in framerates in wine games for example and can cure alot of hiccups in multimedia apps. Discussion: #1: Bernhard Friedreich (bernhard1234) (2009-01-18 15:25:11) wow.. I didn't know about that facts.. I vote for that one! (running both a server and multiple notebooks on openSUSE) #2: Jan Engelhardt (jengelh) (2009-01-19 09:48:49) So why do not you use the RT kernel if your problems are that bad? Also, HPET and tickless is already enabled if you have not noticed. If you suggest disabling Optimize For Size, then I disclaim that you know all of the facts. A smaller kernel results in less instructions to fetch and run, and as such, less execution time to complete a given task. Unless you have specific numbers that an unloaded ATM module slows down your daily operations, it is not going to go away just because you think it is responsible for speed issues. Because as I read the source, it seems to me that it merely introduces one test and branch to the IPv4 ARP code, and that is just so small it is ridiculous to debate about. I do however, would want to see the kernel package being split up so as to have drivers that "probably are not" desktop- related in this decade, like ATM, in a separate installable package. #3: Dean Hilkewich (deanjo13) (2009-01-21 06:12:22) Yes I realize that HPET and tickless are already in there by default. I'm just pointing out settings that do make a difference for desktop use. Optimize for Size (=Os) can in theory reduce the executable size and can in some cases have small increases due to better cache usage, however in real life practice on a desktop you will find that disabling it (-02) does give a real life performance gain. Feel free to benchmark on your own as well (BTW Grub starts looking pretty squished with tones of kernels installed). These settings have been tested tried and true in the mailing lists, forums, etc. The RT kernel still defaults to a 250 Hz timer, Control Group support and Group CPU. All of these hurt multimedia and GL app performance. Easiest way of testing this for yourself is put a demanding game in wine such as command and conquer 3 in wine and play it or try to play high def content on a system with marginal system specs to do so. They make all the world of difference. The reason I recommended removing ATM, Infniband etc etc etc for the same reasons that you would like to see a separate kernel package for little if ever used anymore modules. I'm sure if you went through opensuse-help's own mailing list you can see these configs mentioned more then a few times and the results they give users afterwards. #4: Dmitry Mittov (michael_knight) (2009-01-22 08:40:14) How it will have impact to installation procces? Does user have to choose kernel manually. Or it will be done automatically with help of some criteria? #7: Dean Hilkewich (deanjo13) (2009-01-23 02:26:22) (reply to #4) It doesn't have to impact the installation process at all. What is required to do this is just another .config kernel config file added to the kernel src RPM and when that is built you would have a desktop kernel. The process is really no different then the current kernel choices we have now (rt, pae, default, xen etc). It doesn't even have to really be hosted on the installation DVD/CD medium at all but could be simply one of those extra packages just found on the full OSS repository. No separate installation images are needed but could be made if product creator was massaged a bit more into a end user friendly app or once susestudio goes live one could easily spin a custom dvd for their own use. The key is to get these alternative kernel packages on the official OSS repo. #5: Vasiliy Astanin (madcad) (2009-01-22 17:49:21) May be we should separate not only kernel, but entire images? openSUSE- Desktop.iso contains KDE, Gnome and a lot of userspace software, but no any Apaches, tomcat, or so. + it contains kernel-desktop openSUSE- Server.iso contains no heavy DE, no OpenOffice, no any other large desktop packages - only some extremely light WM - like icewm, but with all server features. + it contains kernel-default, -server, or similar Such splitted images will be much less in size, so maybe server will even fit on CD. This way we'll get something similar to SLES/SLED, but it may be a good tactics ;) #6: Todd R (theblackcat) (2009-01-22 22:19:33) Perhaps when someone is installing their system they can have a selection of a few different pre-configured systems, such as Desktop/Laptop and Server, and then an "Other" section that includes Netbook, Text-only Desktop/Laptop, Text-only Server, Lightweight Desktop/Laptop, Lightweight Server, Real-time System, Workstation, and perhaps a few more advanced configurations that only advanced users would want. Alternatively, you could ask when someone is first installing the system "Are you planning to use this computer primarily as a:" and they can pick either "Desktop/Laptop" or Server. For established setups, having kernel-desktop and kernel-server versions available in the software management could take care of switching, but perhaps a generic Kernel Setup YaST module that allows you to pick what sorts of things you want to serve as well as allowing you to switch to the server kernel (or back) would help. + #8: Stephan Kleine (bitshuffler) (2009-02-23 21:05:37) + Apparently doing stuff like enabling PREEMPT and setting HZ to 1000 + would not only result in a snappier system but also e.g. solve the + glitch problems with pulse audio: https://tango.0pointer.de/pipermail/pulseaudio-discuss/2009-February/003150.... + (considering the amount of bitching about PA that alone should be a + good enough reason to do it ;D) + Even the kernel devs themself say, if I'm not completely mistaken, that + the one kernel for all approach isn't a good idea and that it makes + sense to have different flavors for -desktop & -server with their + settings tuned for the usecase. -- openSUSE Feature: https://features.opensuse.org/305694