Re: Should 80MB of RAM be enough for kernel relinking on i386?
On Thu, Sep 23, 2021 at 09:21:46PM +0100, Stuart Henderson wrote: > (the extra register used by PIE > hurts i386 mode a lot more than amd64 > mode with its extra registers), Just for the sake of correctness: it hurts much less on x86_64, because there is IP-relative addressing for code *and* data. Unless you are using the medium or large code model (> 2GB code or data), functions can compute addresses in a single instruction without a temporary register or binding one to the GOT. So you get a smaller prologue and epilogue in any function that touches a a global variable. Joerg
Re: Should 80MB of RAM be enough for kernel relinking on i386?
You've made a pretty big assumption there. When we see something we don't think is important, we delete the email and carry on with more important things. You think hand-tuning this one paragraph is going to reduce the amount of mail we delete because it doesn't matter? It won't. A large number of inaccurate documentation problems in the world can be solved by deleting the innacurate documentation rather than trying to fine-tune it to be more accurate for the moment, until it becomes inaccurate again. In truth, noone cares about this paragraph. It has been perceveived as a promise. We don't need to make statements people perceive as promises. Patrick Harper wrote: > Because you might not wish to deal with people like me posting dmesg's > of absurdly deficient hardware on the lists. Putting minimum values up > means you can cast off everything you don't want to bother trying to > support as 'not worth your time', without anyone else having to > discover that it wasn't worth their time either. > > On Thu, 23 Sep 2021, at 21:25, Theo de Raadt wrote: > > We don't list memory sizing for other architectures. Why list it for i386? > > > > Why not delete the text? > > > > Because someone wants the truth? You can't handle
Re: Should 80MB of RAM be enough for kernel relinking on i386?
Because you might not wish to deal with people like me posting dmesg's of absurdly deficient hardware on the lists. Putting minimum values up means you can cast off everything you don't want to bother trying to support as 'not worth your time', without anyone else having to discover that it wasn't worth their time either. On Thu, 23 Sep 2021, at 21:25, Theo de Raadt wrote: > We don't list memory sizing for other architectures. Why list it for i386? > > Why not delete the text? > > Because someone wants the truth? You can't handle
Re: Should 80MB of RAM be enough for kernel relinking on i386?
Stuart Henderson wrote: > Nobody should really by using i386 for new systems. The advantages > of running amd64-compatible hardware are too big to ignore. Lower power > consumption, much faster in most cases (the extra register used by PIE > hurts i386 mode a lot more than amd64 mode with its extra registers), > more address space for ASLR, some other security mitigations don't > work on i386, more compatible with software in ports. > > If it's an old system then you already have it so you can just see > for yourself how much space it needs (and make your own decisions on > swap space vs RAM, and whether to disable relinking at boot [just using > it for upgrades/syspatch], and whether to bodge things to use ld.bfd to > save RAM). So much depends on how you're going to use the system that > I don't think it's really useful to publish the numbers. We don't list memory sizing for other architectures. Why list it for i386? Why not delete the text? Because someone wants the truth? You can't handle
Re: Should 80MB of RAM be enough for kernel relinking on i386?
Nobody should really by using i386 for new systems. The advantages of running amd64-compatible hardware are too big to ignore. Lower power consumption, much faster in most cases (the extra register used by PIE hurts i386 mode a lot more than amd64 mode with its extra registers), more address space for ASLR, some other security mitigations don't work on i386, more compatible with software in ports. If it's an old system then you already have it so you can just see for yourself how much space it needs (and make your own decisions on swap space vs RAM, and whether to disable relinking at boot [just using it for upgrades/syspatch], and whether to bodge things to use ld.bfd to save RAM). So much depends on how you're going to use the system that I don't think it's really useful to publish the numbers.
Re: Should 80MB of RAM be enough for kernel relinking on i386?
Le Thu, 23 Sep 2021 14:37:12 +0200, Janne Johansson a écrit : > Den tors 23 sep. 2021 kl 14:27 skrev Patrick Harper : > > > > If there will continue to be a minimum disk value then 600MB wouldn't > > be nearly enough for swap, maybe 2GB for a whole disk? > > Could this handwaving please stop? If anyone wants, make a i386 VM and > do a binary search and record the minimums. > > If this isn't interesting enough, then just end the discussion here. > Whatever the "correct" value is, it will not be decided by a raising > of hands on the maillist about what everyone feels comfortable with, > after adding X,Y,Z and then a margin on that. > > Nobody is sizing and purchasing an i386 system based on these numbers in 2021. > offlist in case this is interesting for someone I tried a few months ago to pinpoint the minimum memory to install and use OpenBSD 6.9 on i386 and found 48 MB to pass the installer and boot. Relinking the kernel was swapping.
Re: Should 80MB of RAM be enough for kernel relinking on i386?
On Thu, Sep 23, 2021 at 8:37 AM Janne Johansson wrote: > Could this handwaving please stop? If anyone wants, make a i386 VM and > do a binary search and record the minimums. > I have done this exercise, but not for kernel relinking -- it was for doing full system rebuilds. Starting with 2.0/i386 I made a VM with 64MB RAM and a 4GB disk, then tried to do a full rebuild of -stable. If the build quit with an error I'd increase the RAM and if the file system filled I'd up the disk space. Then I'd make a new VM for the next release, starting with the minimum RAM and disk required for the previous one (i.e. if requirements had *dropped* dramatically from one release to the next I wouldn't have noticed). For 6.9/i386, 512MB RAM and 512MB swap are sufficient. With 256MB RAM builds may fail. This minimum appears to have taken effect in 6.8/i386. I have not done this test for 7.0 yet, but I was having trouble getting builds to run to completion with only 512MB RAM in -current in February 2021. If this wasn't a temporary thing in -current, I would expect the minimum in 7.0/i386 to be 1GB RAM / 512MB swap. If anyone cares, for 6.2/i386 through 6.7 256MB RAM and 512MB swap is sufficient. For 4.8 through 6.1, 128MB RAM / 512MB swap was enough. amd64 has needed 1GB RAM and 1GB swap to do full system rebuilds since 6.6. For 6.3 through 6.5, 512MB RAM and 1GB swap is sufficient. 6.2 will build with 512MB RAM and 512MB swap. 4.8 through 6.1 will build with 256MB RAM and 512MB swap. 4.4 through 4.7 will build with 128MB RAM and 512MB swap. If it matters, all of this testing was done on an old Dell PowerEdge 2900 III server with dual Xeon E5450 processors and 48GB RAM, running VMware ESXi 5.5 Update 2. All VMs were "version 8" guests in VMware, and all VMs were configured with 1 virtual cpu socket with 1 virtual core until release 3.5, then changed to 1 socket / 2 cores for 3.6 and later releases. -ken
Re: Should 80MB of RAM be enough for kernel relinking on i386?
Den tors 23 sep. 2021 kl 14:27 skrev Patrick Harper : > > If there will continue to be a minimum disk value then 600MB wouldn't > be nearly enough for swap, maybe 2GB for a whole disk? Could this handwaving please stop? If anyone wants, make a i386 VM and do a binary search and record the minimums. If this isn't interesting enough, then just end the discussion here. Whatever the "correct" value is, it will not be decided by a raising of hands on the maillist about what everyone feels comfortable with, after adding X,Y,Z and then a margin on that. Nobody is sizing and purchasing an i386 system based on these numbers in 2021. -- May the most significant bit of your life be positive.
Re: Should 80MB of RAM be enough for kernel relinking on i386?
If there will continue to be a minimum disk value then 600MB wouldn't be nearly enough for swap, maybe 2GB for a whole disk? -- Patrick Harper paia...@fastmail.com On Thu, 23 Sep 2021, at 11:29, Zé Loff wrote: > IMHO, stating minimum disk space requirements might be useful for > determining partition sizes e.g. when setting up multibooting, creating > disk images for virtual machines, etc. I agree that nowadays 600Mb > might be easy to come by for a i386 machine (I did have to upgrade the > 512Mb CF cards on my soekris boxes, but I know that's a corner case), > but still. I don't think there is a problem needing to be fixed, here. > > --
Re: Should 80MB of RAM be enough for kernel relinking on i386?
On Thu, Sep 23, 2021 at 11:29:53AM +0100, Zé Loff wrote: > On Wed, Sep 22, 2021 at 05:27:30PM +0100, Patrick Harper wrote: > > If the situation isn't going to change anytime soon then I have some > > diffs for INSTALL.i386 and INSTALL.amd64. The latter has not specified > > disk requirements, I guess since anyone who owns an amd64 system will > > very likely be using a disk big enough for X, so I figured that the > > same would apply to any user of an i386 system that meets the proposed > > minimum RAM. These are based on the 2021-09-21 snapshot versions. > > > > --- INSTALL.i386.txtWed Sep 22 16:52:38 2021 > > +++ INSTALL.i386_newWed Sep 22 16:51:17 2021 > > @@ -201,10 +201,7 @@ OpenBSD/i386 7.0 supports most SMP (Symmetrical > > MultiP > > systems. To support SMP operation, a separate SMP kernel (bsd.mp) > > is included with the installation file sets. > > > > -The minimal configuration to install the system is 32MB of RAM and > > -at least 250MB of disk space to accommodate the `base' set. > > -To install the entire system, at least 600MB of disk are required, > > -and to run X or compile the system, more RAM is recommended. > > +The minimal configuration to install the system is 512MB of RAM. > > > > Please refer to the website for a full list of supported hardware: > > https://www.openbsd.org/i386.html > > > > > > --- INSTALL.amd64.txt Wed Sep 22 16:52:48 2021 > > +++ INSTALL.amd64_new Wed Sep 22 16:51:12 2021 > > @@ -202,6 +202,8 @@ is included with the installation file sets. > > OpenBSD/amd64 7.0 supports both UEFI/GPT booting and BIOS/MBR > > booting. > > > > +The minimal configuration to install the system is 512MB of RAM. > > + > > Please refer to the website for a full list of supported hardware. > > > > https://www.openbsd.org/amd64.html > > > > > > Patrick Harper > > > > IMHO, stating minimum disk space requirements might be useful for > determining partition sizes e.g. when setting up multibooting, creating > disk images for virtual machines, etc. I agree that nowadays 600Mb > might be easy to come by for a i386 machine (I did have to upgrade the > 512Mb CF cards on my soekris boxes, but I know that's a corner case), > but still. I don't think there is a problem needing to be fixed, here. > Just a minor clarification about my statement above: I meant that _presenting_ disk size requirements isn't a problem in itself (other than some maintenance overhead, of course). Stating outdated values obviously is. Sorry for the noise Z --
Re: Should 80MB of RAM be enough for kernel relinking on i386?
On Wed, Sep 22, 2021 at 05:27:30PM +0100, Patrick Harper wrote: > If the situation isn't going to change anytime soon then I have some > diffs for INSTALL.i386 and INSTALL.amd64. The latter has not specified > disk requirements, I guess since anyone who owns an amd64 system will > very likely be using a disk big enough for X, so I figured that the > same would apply to any user of an i386 system that meets the proposed > minimum RAM. These are based on the 2021-09-21 snapshot versions. > > --- INSTALL.i386.txtWed Sep 22 16:52:38 2021 > +++ INSTALL.i386_newWed Sep 22 16:51:17 2021 > @@ -201,10 +201,7 @@ OpenBSD/i386 7.0 supports most SMP (Symmetrical > MultiP > systems. To support SMP operation, a separate SMP kernel (bsd.mp) > is included with the installation file sets. > > -The minimal configuration to install the system is 32MB of RAM and > -at least 250MB of disk space to accommodate the `base' set. > -To install the entire system, at least 600MB of disk are required, > -and to run X or compile the system, more RAM is recommended. > +The minimal configuration to install the system is 512MB of RAM. > > Please refer to the website for a full list of supported hardware: > https://www.openbsd.org/i386.html > > > --- INSTALL.amd64.txt Wed Sep 22 16:52:48 2021 > +++ INSTALL.amd64_new Wed Sep 22 16:51:12 2021 > @@ -202,6 +202,8 @@ is included with the installation file sets. > OpenBSD/amd64 7.0 supports both UEFI/GPT booting and BIOS/MBR > booting. > > +The minimal configuration to install the system is 512MB of RAM. > + > Please refer to the website for a full list of supported hardware. > > https://www.openbsd.org/amd64.html > > > Patrick Harper > IMHO, stating minimum disk space requirements might be useful for determining partition sizes e.g. when setting up multibooting, creating disk images for virtual machines, etc. I agree that nowadays 600Mb might be easy to come by for a i386 machine (I did have to upgrade the 512Mb CF cards on my soekris boxes, but I know that's a corner case), but still. I don't think there is a problem needing to be fixed, here. --
Re: Should 80MB of RAM be enough for kernel relinking on i386?
If the situation isn't going to change anytime soon then I have some diffs for INSTALL.i386 and INSTALL.amd64. The latter has not specified disk requirements, I guess since anyone who owns an amd64 system will very likely be using a disk big enough for X, so I figured that the same would apply to any user of an i386 system that meets the proposed minimum RAM. These are based on the 2021-09-21 snapshot versions. --- INSTALL.i386.txtWed Sep 22 16:52:38 2021 +++ INSTALL.i386_newWed Sep 22 16:51:17 2021 @@ -201,10 +201,7 @@ OpenBSD/i386 7.0 supports most SMP (Symmetrical MultiP systems. To support SMP operation, a separate SMP kernel (bsd.mp) is included with the installation file sets. -The minimal configuration to install the system is 32MB of RAM and -at least 250MB of disk space to accommodate the `base' set. -To install the entire system, at least 600MB of disk are required, -and to run X or compile the system, more RAM is recommended. +The minimal configuration to install the system is 512MB of RAM. Please refer to the website for a full list of supported hardware: https://www.openbsd.org/i386.html --- INSTALL.amd64.txt Wed Sep 22 16:52:48 2021 +++ INSTALL.amd64_new Wed Sep 22 16:51:12 2021 @@ -202,6 +202,8 @@ is included with the installation file sets. OpenBSD/amd64 7.0 supports both UEFI/GPT booting and BIOS/MBR booting. +The minimal configuration to install the system is 512MB of RAM. + Please refer to the website for a full list of supported hardware. https://www.openbsd.org/amd64.html Patrick Harper
