On Mon, 07 Sep 2015 09:43:54 +0200, Basil Chupin wrote:
On 04/09/15 17:53, Takashi Iwai wrote:
On 03/09/15 19:26, Michal Marek wrote:
Hi,
since Leap is sharing code with SLE and it will eventually share the kernel as well, I would like to align the config/ directory with the SLE kernel where practical. ia64 has already been deleted, same happened to the trace flavors. We probably want to keep the 32bit ARM, PPC and x86 architectures, to make it easier to build Leap ports for those architectures. What we can drop is the -desktop flavor. Since openSUSE releases have been using this flavor by default, I assume that this is what the majority of users are running, so we probably want to keep some of the settings of the -desktop flavor, to make the transition seamless. Therefore, I propose the following:
- Set CONFIG_PREEMPT=y, CONFIG_HZ=1000 in i386/pae and x86_64/default - Set the sysctl default vm.dirty_ratio=20 for these two flavors - Make i386/pae and x86_64/default obsolete kernel-desktop
Left for discussion is whether PREEMPT and HZ=1000 are actually worth it even on desktop. The setting can be flipped back later if there is a consensus. What we will definitely lose are the various builtin driver choices of the -desktop flavor. Merging these with the SLE kernel configs would constantly result in conflicts, while the boot time gains are negligible. And we will lose the placebo effect of the kernel having "desktop" in its name.
Michal Why is always necessary to change things when things are running smoothly? Why? Because having two flavors costs very much: it costs double for
On Fri, 04 Sep 2015 09:33:10 +0200, Basil Chupin wrote: maintenance, and it costs double for resources. As you might know, the kernel package is neither small nor trivial package.
In your own words, "What we will definitely lose are the various builtin driver choices of the -desktop flavor. Merging these with the SLE kernel configs would constantly result in conflicts.....", so why create avoidable angst and gnashing of teeth by users? It's a technical detail, and we care not to break things. That's why we're *discussing* here now. If you have an enough technical reason not to do that (or doing other way), please let us know. Your comment above looks more like a FUD without actual evaluation.
I am not aware of any rule regarding discussion which disallows questions being asked. Or is asking questions a no-no only if it has anything to do with openSUSE?
Well, the tone of the sentence "why create avoidable angst and gnashing of teeth by users?" doesn't sound like a pure (preferably technical) question but rather offensive. If it were a neutral tone, it would have been received differently.
General speaking, this change will give more merits to users, too. The situation where we have default and desktop flavors is weird. Why desktop flavor is used as default installation while there is default flavor? It was intended as a short-time stop-gap, but this was dragged too long. So, reducing such a confusion is good for users.
Also, changing from built-in to modules will give more merits. In that way, you can update the functionality more easily. For example, with the current desktop flavor, if you want to change something in ext4, you'd have to replace the whole kernel because it's built in. If it's a module, you can just install a KMP for testing and uninstall for reverting.
Again, such built-in config was also considered as a temporary stop gap at the time we aimed more for speed on a slow Netbooks, and this won't justify any longer.
So, think this action from another POV: it's a good chance to "fix" such weirdness.
My question,"Why?", is simply asking why change things when:
1) there was a legitimate reason for creating another flavour of the kernel - the -desktop - with its special settings (I refer,eg, to the 'CONFIG_HZ=1000' in particular which I had to apply in my early compilations of the kernel to get better performance from it for my desktop) when there already were the PAE kernel, the Default kernel, and then the XEN kernel and the other to cater for the mini computer owners (cannot remember its name); and
The changes we're considering are, more exactly, not "drop desktop flavor" but rather "merge desktop and default flavors to a single default flavor". The key configurations about the performance are more aligned to the current desktop flavor, so far. In anyway, your observation about CONFIG_HZ=1000 is a myth nowadays. CONFIG_HZ=1000 is mostly superfluous when combined with CONFIG_PREEMPT. Most of other distros take CONFIG_HZ=250, IIRC. As already explained, the setup was introduced at the time we worked on Meego on Netbooks. The boot speed was the first priority, and the response on the slow machine was the second. The last comes to performance. But this was the past experience, and doesn't match with the recent machines at all. We'd need to revise these setups, sooner or later.
2) nobody complained for years about compiling and maintaining and providing all the variants of the kernel.
No, most of kernel developers have been complaining about this duplication since the introduction of desktop flavor. It didn't come up to user list so often just because there were mostly on internal kernel ML. No one ever liked desktop flavor, but this hack was kept only because of laziness (*shame*).
But suddenly now it has become a "burden" and a strain on resources! And yet we see almost a daily release of an almost unusable piece of software called Tumbleweed which is 4.3GB big and must take a huge amount of resources to produce - but that's OK, right?
The build of kernel takes lots of resources, both of CPU and space. And this happens on each kernel branch and each user branch. Of course there are lots of other resource hogs in other packages, but the significant difference is that kernel is the most frequently modified packages ever. Reduction of one kernel flavor will help for kernel developers, not only for users, a lot.
Keeping the above in mind is the reason why I asked another question which I will now repeat and quote in full - please forgive!:
In your own words, "What we will definitely lose are the various builtin driver choices of the -desktop flavor. Merging these with the SLE kernel configs would constantly result in conflicts.....", so why create avoidable angst and gnashing of teeth by users?
I hope my previous and this replies answer your questions enough. Takashi -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-kernel+owner@opensuse.org