Switching Fedora to pae kernel by default?
This probably comes up once in a while, thought I'd raise it again. I'd like to suggest switching the default kernel to -PAE on machines that support it, for the following reasons: - many machines have 4GB+ these days, even desktops - NX is only available with -PAE, improves security - kvm is significantly faster on AMD when PAE is selected (since we don't support NPT on non-PAE) Not subscribed - please copy. -- error compiling committee.c: too many arguments to function ___ Fedora-kernel-list mailing list Fedora-kernel-list@redhat.com https://www.redhat.com/mailman/listinfo/fedora-kernel-list
Re: Switching Fedora to pae kernel by default?
On Mon, Jan 19, 2009 at 03:49:20PM +0200, Avi Kivity wrote: > This probably comes up once in a while, thought I'd raise it again. > > I'd like to suggest switching the default kernel to -PAE on machines > that support it, for the following reasons: > > - many machines have 4GB+ these days, even desktops > - NX is only available with -PAE, improves security > - kvm is significantly faster on AMD when PAE is selected (since we > don't support NPT on non-PAE) What's needed to set this by default is changes in anaconda. They have their own list at anaconda-l...@redhat.com Dave -- http://www.codemonkey.org.uk ___ Fedora-kernel-list mailing list Fedora-kernel-list@redhat.com https://www.redhat.com/mailman/listinfo/fedora-kernel-list
Re: Switching Fedora to pae kernel by default?
Dave Jones (da...@redhat.com) said: > On Mon, Jan 19, 2009 at 03:49:20PM +0200, Avi Kivity wrote: > > This probably comes up once in a while, thought I'd raise it again. > > > > I'd like to suggest switching the default kernel to -PAE on machines > > that support it, for the following reasons: > > > > - many machines have 4GB+ these days, even desktops > > - NX is only available with -PAE, improves security > > - kvm is significantly faster on AMD when PAE is selected (since we > > don't support NPT on non-PAE) > > What's needed to set this by default is changes in anaconda. > They have their own list at anaconda-l...@redhat.com anaconda-devel-list, actually. But I could have sworn we already did this. Bill ___ Fedora-kernel-list mailing list Fedora-kernel-list@redhat.com https://www.redhat.com/mailman/listinfo/fedora-kernel-list
Re: Switching Fedora to pae kernel by default?
On Mon, Jan 19, 2009 at 11:23:26AM -0500, Bill Nottingham wrote: > Dave Jones (da...@redhat.com) said: > > On Mon, Jan 19, 2009 at 03:49:20PM +0200, Avi Kivity wrote: > > > This probably comes up once in a while, thought I'd raise it again. > > > > > > I'd like to suggest switching the default kernel to -PAE on machines > > > that support it, for the following reasons: > > > > > > - many machines have 4GB+ these days, even desktops > > > - NX is only available with -PAE, improves security > > > - kvm is significantly faster on AMD when PAE is selected (since we > > > don't support NPT on non-PAE) > > > > What's needed to set this by default is changes in anaconda. > > They have their own list at anaconda-l...@redhat.com > > anaconda-devel-list, actually. But I could have sworn we already did this. > Unless we keep the non-PAE i586 kernel around as a fallback, we're not going to be able to boot on a whole raft of crappy i386 chips (original Pentium M most notably...) regards, Kyle ___ Fedora-kernel-list mailing list Fedora-kernel-list@redhat.com https://www.redhat.com/mailman/listinfo/fedora-kernel-list
Re: Switching Fedora to pae kernel by default?
On Monday, January 19 2009, Bill Nottingham said: > Dave Jones (da...@redhat.com) said: > > On Mon, Jan 19, 2009 at 03:49:20PM +0200, Avi Kivity wrote: > > > This probably comes up once in a while, thought I'd raise it again. > > > > > > I'd like to suggest switching the default kernel to -PAE on machines > > > that support it, for the following reasons: > > > > > > - many machines have 4GB+ these days, even desktops > > > - NX is only available with -PAE, improves security > > > - kvm is significantly faster on AMD when PAE is selected (since we > > > don't support NPT on non-PAE) > > > > What's needed to set this by default is changes in anaconda. > > They have their own list at anaconda-l...@redhat.com > > anaconda-devel-list, actually. But I could have sworn we already did this. Well, we're not going to make the change unless kernel guys want us to. That said, we currently do install the PAE kernel if you have 4 GB+ of RAM[1]. Switching to it by default is problematic because then we're back to using different kernels for different cases and it also makes the 'what do you with the live image' case a lot more complex. The _real_ fix here is to get PAE runtime much like was finally done with SMP :-) Jeremy [1] Well, any memory above 4 GB actually -- so if you have a machine with a large hole and only 3 GB of RAM, you could end up with the PAE kernel ___ Fedora-kernel-list mailing list Fedora-kernel-list@redhat.com https://www.redhat.com/mailman/listinfo/fedora-kernel-list
Re: Switching Fedora to pae kernel by default?
Bill Nottingham wrote: Dave Jones (da...@redhat.com) said: On Mon, Jan 19, 2009 at 03:49:20PM +0200, Avi Kivity wrote: > This probably comes up once in a while, thought I'd raise it again. > > I'd like to suggest switching the default kernel to -PAE on machines > that support it, for the following reasons: > > - many machines have 4GB+ these days, even desktops > - NX is only available with -PAE, improves security > - kvm is significantly faster on AMD when PAE is selected (since we > don't support NPT on non-PAE) What's needed to set this by default is changes in anaconda. They have their own list at anaconda-l...@redhat.com anaconda-devel-list, actually. But I could have sworn we already did this. Just tested; F10 i386 still installs a non-PAE kernel. -- error compiling committee.c: too many arguments to function ___ Fedora-kernel-list mailing list Fedora-kernel-list@redhat.com https://www.redhat.com/mailman/listinfo/fedora-kernel-list
Re: Switching Fedora to pae kernel by default?
Jeremy Katz wrote: That said, we currently do install the PAE kernel if you have 4 GB+ of RAM[1]. Switching to it by default is problematic because then we're back to using different kernels for different cases You have that now, don't you? One case for <4GB and one for >=4GB. Worse, if you install more memory, the kernel doesn't see it. Downgrading your CPU to one which does not support PAE should be rare. and it also makes the 'what do you with the live image' case a lot more complex. I'd just go with PAE here. The _real_ fix here is to get PAE runtime much like was finally done with SMP :-) Patches, as they say, are welcome. But you could install both kernels and have the bootloaded choose (sticks wax balls into ears). -- error compiling committee.c: too many arguments to function ___ Fedora-kernel-list mailing list Fedora-kernel-list@redhat.com https://www.redhat.com/mailman/listinfo/fedora-kernel-list
Re: Switching Fedora to pae kernel by default?
Kyle McMartin wrote: On Mon, Jan 19, 2009 at 11:23:26AM -0500, Bill Nottingham wrote: Dave Jones (da...@redhat.com) said: On Mon, Jan 19, 2009 at 03:49:20PM +0200, Avi Kivity wrote: > This probably comes up once in a while, thought I'd raise it again. > > I'd like to suggest switching the default kernel to -PAE on machines > that support it, for the following reasons: > > - many machines have 4GB+ these days, even desktops > - NX is only available with -PAE, improves security > - kvm is significantly faster on AMD when PAE is selected (since we > don't support NPT on non-PAE) What's needed to set this by default is changes in anaconda. They have their own list at anaconda-l...@redhat.com Unless we keep the non-PAE i586 kernel around as a fallback, we're not going to be able to boot on a whole raft of crappy i386 chips (original Pentium M most notably...) I'm not suggesting dropping non-PAE. Simply defaulting to PAE where possible. Are Pentium Ms (really the memory that comes with them) actually capable of running recent Fedoras? I'm talking desktop, not I'm-using-my-laptop-as-a-firewall-just-because-I-can. -- error compiling committee.c: too many arguments to function ___ Fedora-kernel-list mailing list Fedora-kernel-list@redhat.com https://www.redhat.com/mailman/listinfo/fedora-kernel-list
Re: Switching Fedora to pae kernel by default?
On Monday, January 19 2009, Avi Kivity said: > Jeremy Katz wrote: >> That said, we currently do install the PAE kernel if you have 4 GB+ of >> RAM[1]. Switching to it by default is problematic because then we're >> back to using different kernels for different cases > > You have that now, don't you? One case for <4GB and one for >=4GB. > Worse, if you install more memory, the kernel doesn't see it. > > Downgrading your CPU to one which does not support PAE should be rare. Yes, but at least the "running a different kernel" case is currently the relatively rare one. >> and it also makes >> the 'what do you with the live image' case a lot more complex. > > I'd just go with PAE here. Can't do so -- the live image is definitely used on a lot of hardware that isn't PAE capable. Many/most Pentium M's didn't support it, the OLPC doesn't[1]. And those are common hardware targets for the live image >> The _real_ fix here is to get PAE runtime much like was finally done >> with SMP :-) > > Patches, as they say, are welcome. Low-level x86 setup code isn't quite my forte... Hence I go for goading others into doing it ;-) > But you could install both kernels > and have the bootloaded choose (sticks wax balls into ears). Want to write code for syslinux and grub to do the auto-choosing? Then we also have to figure out a way to shoe-horn another 50 MB of stuff into the already full live image Jeremy ___ Fedora-kernel-list mailing list Fedora-kernel-list@redhat.com https://www.redhat.com/mailman/listinfo/fedora-kernel-list
Re: Switching Fedora to pae kernel by default?
On Mon, 2009-01-19 at 19:31 +0200, Avi Kivity wrote: > Kyle McMartin wrote: > > On Mon, Jan 19, 2009 at 11:23:26AM -0500, Bill Nottingham wrote: > > > >> Dave Jones (da...@redhat.com) said: > >> > >>> On Mon, Jan 19, 2009 at 03:49:20PM +0200, Avi Kivity wrote: > >>> > This probably comes up once in a while, thought I'd raise it again. > >>> > > >>> > I'd like to suggest switching the default kernel to -PAE on machines > >>> > that support it, for the following reasons: > >>> > > >>> > - many machines have 4GB+ these days, even desktops > >>> > - NX is only available with -PAE, improves security > >>> > - kvm is significantly faster on AMD when PAE is selected (since we > >>> > don't support NPT on non-PAE) > >>> > >>> What's needed to set this by default is changes in anaconda. > >>> They have their own list at anaconda-l...@redhat.com > >>> > > Unless we keep the non-PAE i586 kernel around as a fallback, we're not > > going to be able to boot on a whole raft of crappy i386 chips (original > > Pentium M most notably...) > > I'm not suggesting dropping non-PAE. Simply defaulting to PAE where > possible. > > Are Pentium Ms (really the memory that comes with them) actually capable > of running recent Fedoras? I'm talking desktop, not > I'm-using-my-laptop-as-a-firewall-just-because-I-can. I've got a P3 (Coppermine) with 256M memory running F10. My significant other took it with her to Antarctica (Well F9 has been to Antarctica but it'll be F10 in Antarctica next month). You can only run one app at a time and have to be patient, but it's perfectly usable (and noone cares if this laptop is lost, stolen or destroyed [aside from her being pissed she lost all her research data]). I wouldn't/couldn't to use it as a daily machine, so while I'm in favor of -PAE default, F10 is "usable" on such small machines. I don't care if old machines need some bit twiddling to get to work, but we aren't dead yet :) -Eric ___ Fedora-kernel-list mailing list Fedora-kernel-list@redhat.com https://www.redhat.com/mailman/listinfo/fedora-kernel-list
Re: Switching Fedora to pae kernel by default?
Avi Kivity (a...@redhat.com) said: > Are Pentium Ms (really the memory that comes with them) actually capable > of running recent Fedoras? I'm talking desktop, not > I'm-using-my-laptop-as-a-firewall-just-because-I-can. Sure, I had a T40 that had 1.5GB of memory in it, and it could have taken more. Bill ___ Fedora-kernel-list mailing list Fedora-kernel-list@redhat.com https://www.redhat.com/mailman/listinfo/fedora-kernel-list
Re: Switching Fedora to pae kernel by default?
On Mon, 19 Jan 2009 19:31:12 +0200, Avi Kivity wrote: > Are Pentium Ms (really the memory that comes with them) actually capable > of running recent Fedoras? I'm talking desktop, not > I'm-using-my-laptop-as-a-firewall-just-because-I-can. If only it were laptops. I think they still sell systems like this: [zait...@mallorn ~]$ more /proc/cpuinfo processor : 0 vendor_id : CentaurHauls cpu family : 6 model : 7 model name : VIA Samuel 2 stepping: 3 cpu MHz : 800.065 cache size : 64 KB fdiv_bug: no hlt_bug : no f00f_bug: no coma_bug: no fpu : yes fpu_exception : yes cpuid level : 1 wp : yes flags : fpu de tsc msr cx8 mtrr pge mmx 3dnow bogomips: 1601.64 clflush size: 32 [zait...@mallorn ~]$ You point about non-default kernel is well taken though. I'm not against making PAE default as long as some king of alternative is provided. BTW, does anyone know if the Geode in OLPC XO has PAE? -- Pete ___ Fedora-kernel-list mailing list Fedora-kernel-list@redhat.com https://www.redhat.com/mailman/listinfo/fedora-kernel-list
Re: Switching Fedora to pae kernel by default?
On Mon, Jan 19, 2009 at 11:24:14AM -0700, Pete Zaitcev wrote: > On Mon, 19 Jan 2009 19:31:12 +0200, Avi Kivity wrote: > > > Are Pentium Ms (really the memory that comes with them) actually capable > > of running recent Fedoras? I'm talking desktop, not > > I'm-using-my-laptop-as-a-firewall-just-because-I-can. > > If only it were laptops. I think they still sell systems like this: > > [zait...@mallorn ~]$ more /proc/cpuinfo > processor: 0 > vendor_id: CentaurHauls > cpu family : 6 > model: 7 > model name : VIA Samuel 2 The samuel 2 stopped being made ~5 years ago. VIA have been PAE capable since the Nehemiah generation. Dave -- http://www.codemonkey.org.uk ___ Fedora-kernel-list mailing list Fedora-kernel-list@redhat.com https://www.redhat.com/mailman/listinfo/fedora-kernel-list
Re: Switching Fedora to pae kernel by default?
On Mon, Jan 19, 2009 at 11:24:14AM -0700, Pete Zaitcev wrote: > BTW, does anyone know if the Geode in OLPC XO has PAE? > The PAE bit in %cr4 is listed as reserved in the geode databook the olpc site links to, so my guess is no. :\ regards, Kyle ___ Fedora-kernel-list mailing list Fedora-kernel-list@redhat.com https://www.redhat.com/mailman/listinfo/fedora-kernel-list
Re: Switching Fedora to pae kernel by default?
On Mon, Jan 19, 2009 at 07:31:12PM +0200, Avi Kivity wrote: > Kyle McMartin wrote: >> On Mon, Jan 19, 2009 at 11:23:26AM -0500, Bill Nottingham wrote: >> >>> Dave Jones (da...@redhat.com) said: On Mon, Jan 19, 2009 at 03:49:20PM +0200, Avi Kivity wrote: > This probably comes up once in a while, thought I'd raise it again. > > I'd like to suggest switching the default kernel to -PAE on machines > that support it, for the following reasons: > > - many machines have 4GB+ these days, even desktops > - NX is only available with -PAE, improves security > - kvm is significantly faster on AMD when PAE is selected (since we > don't support NPT on non-PAE) What's needed to set this by default is changes in anaconda. They have their own list at anaconda-l...@redhat.com >> Unless we keep the non-PAE i586 kernel around as a fallback, we're not >> going to be able to boot on a whole raft of crappy i386 chips (original >> Pentium M most notably...) > > I'm not suggesting dropping non-PAE. Simply defaulting to PAE where > possible. > > Are Pentium Ms (really the memory that comes with them) actually capable > of running recent Fedoras? I'm talking desktop, not > I'm-using-my-laptop-as-a-firewall-just-because-I-can. > Absolutely, I've got a Thinkpad T42 here that does just fine on fedora 10. Unless of course, I try to load a PAE enabled kernel on it. I've not looked into it at all, but this thread got me thinking, is there any particular reason that we can't merge the pae and non-pae kernels using the same alternatives approach we used to merge smp & up? Neil /* *Neil Horman *919-754-4323 / ___ Fedora-kernel-list mailing list Fedora-kernel-list@redhat.com https://www.redhat.com/mailman/listinfo/fedora-kernel-list
Re: Switching Fedora to pae kernel by default?
On Mon, Jan 19, 2009 at 01:36:08PM -0500, Neil Horman wrote: > Absolutely, I've got a Thinkpad T42 here that does just fine on fedora 10. > Unless of course, I try to load a PAE enabled kernel on it. > > I've not looked into it at all, but this thread got me thinking, is there any > particular reason that we can't merge the pae and non-pae kernels using the > same > alternatives approach we used to merge smp & up? > I looked into this several years ago, it's actually fairly gnarly since depending on PAE we set up the swapper page tables differently, and other ugly differences. I should resurrect the patch set, though I think rationalizing it with the Xen merge might be more pain than it's worth... last time I looked at it there was a ridiculous amount of rejects. It was pretty close to booting (though I had to hack the bootloader to get a PAE enable bit so people without the bit could turn it off.) regards, Kyle ___ Fedora-kernel-list mailing list Fedora-kernel-list@redhat.com https://www.redhat.com/mailman/listinfo/fedora-kernel-list
Re: Switching Fedora to pae kernel by default?
On Mon, 2009-01-19 at 11:24 -0700, Pete Zaitcev wrote: > BTW, does anyone know if the Geode in OLPC XO has PAE? This is off a C2: [o...@xo-10-dd-46 ~]$ cat /proc/cpuinfo processor : 0 vendor_id : AuthenticAMD cpu family : 5 model : 10 model name : Geode(TM) Integrated Processor by AMD PCS stepping: 2 cpu MHz : 430.931 cache size : 128 KB fdiv_bug: no hlt_bug : no f00f_bug: no coma_bug: no fpu : yes fpu_exception : yes cpuid level : 1 wp : yes flags : fpu de pse tsc msr cx8 sep pge cmov clflush mmx mmxext 3dnowext 3dnow bogomips: 863.19 clflush size: 32 -- Ignacio Vazquez-Abrams PLEASE don't CC me; I'm already subscribed ___ Fedora-kernel-list mailing list Fedora-kernel-list@redhat.com https://www.redhat.com/mailman/listinfo/fedora-kernel-list
Re: Switching Fedora to pae kernel by default?
Kyle McMartin wrote: > On Mon, Jan 19, 2009 at 01:36:08PM -0500, Neil Horman wrote: >> Absolutely, I've got a Thinkpad T42 here that does just fine on fedora 10. >> Unless of course, I try to load a PAE enabled kernel on it. >> >> I've not looked into it at all, but this thread got me thinking, is there any >> particular reason that we can't merge the pae and non-pae kernels using the >> same >> alternatives approach we used to merge smp & up? >> > > I looked into this several years ago, it's actually fairly gnarly since > depending on PAE we set up the swapper page tables differently, and > other ugly differences. > > I should resurrect the patch set, though I think rationalizing it with the > Xen merge might be more pain than it's worth... last time I looked at it > there was a ridiculous amount of rejects. Well, it depends on if you are talking about the non-upstream Xen patch, or the current upstream pv_ops. The former is all but dead, so you don't have to worry about that, and the latter *should* (famous last words) mostly stay out of your way through pv_ops. Though I haven't gone in and implemented it myself, so it's easy for me to say :). I think choosing PAE at runtime would be the ideal situation, if we can get there. -- Chris Lalancette ___ Fedora-kernel-list mailing list Fedora-kernel-list@redhat.com https://www.redhat.com/mailman/listinfo/fedora-kernel-list