Re: Kernel/Userland Mem-Space Tuning (1/3 on IA32)
Hello. I read about address space division of recent operating systems like Linux and Windows XP. In both cases, the whole address space of the 32 or 64 Bit system is divided into halfes, 2GB for kernel, 2 GB for process(es) (speaking in 32Bit words). The same in 64bit systems like AMD64. Those who happily utilize an AMD64 based machine are not (yet) involved by this problem, but on recent 32 Bit architectures someone can run out of process space, like me! Some geophysical modelling software needs more than the allowed 2GB address space and therefore I would like to ask whether FreeBSD (my preferred OS) has a 'knob' to change the kernel/userland parity of the address space like it is done in Windows with a special knob at boot time (/W3GB I think, but I'm not sure about the exakt syntax but I know someone can change the half by half parity towards 1 to 3 in XP). I'm not sure whether FreeBSD divides kernel/userland address space this way, I know Linux and Windows does and on Windows we changed this (not yet on Linux and not yet on our FreeBSD machines (OS version 5.0, mostly FreeBSD 5.3-R or 5.4-PRERELEASE). Any help is appreciated. FreeBSD divides the 32bit virtual address space with 1GB for the kernel and 3GB for user processes. This can be changed with some kernel compile- time constants (primarily KVA_PAGES, however NKPT may also need to be increased if the kernel address space is increased). -DG David G. Lawrence President Download Technologies, Inc. - http://www.downloadtech.com - (866) 399 8500 TeraSolutions, Inc. - http://www.terasolutions.com - (888) 346 7175 The FreeBSD Project - http://www.freebsd.org Pave the road of life with opportunities. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Kernel/Userland Mem-Space Tuning (1/3 on IA32)
David G. Lawrence wrote: Hello. I read about address space division of recent operating systems like Linux and Windows XP. In both cases, the whole address space of the 32 or 64 Bit system is divided into halfes, 2GB for kernel, 2 GB for process(es) (speaking in 32Bit words). The same in 64bit systems like AMD64. Those who happily utilize an AMD64 based machine are not (yet) involved by this problem, but on recent 32 Bit architectures someone can run out of process space, like me! Some geophysical modelling software needs more than the allowed 2GB address space and therefore I would like to ask whether FreeBSD (my preferred OS) has a 'knob' to change the kernel/userland parity of the address space like it is done in Windows with a special knob at boot time (/W3GB I think, but I'm not sure about the exakt syntax but I know someone can change the half by half parity towards 1 to 3 in XP). I'm not sure whether FreeBSD divides kernel/userland address space this way, I know Linux and Windows does and on Windows we changed this (not yet on Linux and not yet on our FreeBSD machines (OS version 5.0, mostly FreeBSD 5.3-R or 5.4-PRERELEASE). Any help is appreciated. FreeBSD divides the 32bit virtual address space with 1GB for the kernel and 3GB for user processes. This can be changed with some kernel compile- time constants (primarily KVA_PAGES, however NKPT may also need to be increased if the kernel address space is increased). -DG David G. Lawrence President Download Technologies, Inc. - http://www.downloadtech.com - (866) 399 8500 TeraSolutions, Inc. - http://www.terasolutions.com - (888) 346 7175 The FreeBSD Project - http://www.freebsd.org Pave the road of life with opportunities. Dear David. Thank you very much. I assumed FreeBSD do the same like Linux, but don't obviously. I found a lot of tweaking kernel parameters, KVA_PAGES VM_KMEM_SIZE_SCALE VM_KMEM_SIZE_MAX VM_KMEM_SIZE Reading some comments in sys/kern/kern_malloc.c make be a bit confused, I do not know much about kernel's interna. It is nice to hear that FreeBSD do a 1/3 division, I expected a 2/2 division like Linux does. So no need for anything changing. Can someone please explain NKPT? I'm simply curious, didn't found a satisfying answer via google, but a lot of source code with this in ... Thanks Oliver ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Kernel/Userland Mem-Space Tuning (1/3 on IA32)
sure about the exakt syntax but I know someone can change the half by half parity towards 1 to 3 in XP). I'm not sure whether FreeBSD divides kernel/userland address space this way, I know Linux and Windows does and on Windows we changed this (not yet on Linux and not yet on our FreeBSD machines (OS version 5.0, mostly FreeBSD 5.3-R or 5.4-PRERELEASE). Any help is appreciated. FreeBSD divides the 32bit virtual address space with 1GB for the kernel and 3GB for user processes. This can be changed with some kernel compile- time constants (primarily KVA_PAGES, however NKPT may also need to be increased if the kernel address space is increased). ... Dear David. Thank you very much. I assumed FreeBSD do the same like Linux, but don't obviously. I found a lot of tweaking kernel parameters, KVA_PAGES VM_KMEM_SIZE_SCALE VM_KMEM_SIZE_MAX VM_KMEM_SIZE The last three are not related to the address space division and you should not change those under normal circumstance. Reading some comments in sys/kern/kern_malloc.c make be a bit confused, I do not know much about kernel's interna. It is nice to hear that FreeBSD do a 1/3 division, I expected a 2/2 division like Linux does. So no need for anything changing. It's a 1:4 ratio. Can someone please explain NKPT? I'm simply curious, didn't found a satisfying answer via google, but a lot of source code with this in ... It's the number of page table pages that are assigned to the kernel address space. Each page maps 4MB, so 256 (the default) provides for 1GB of kernel virtual address space, leaving 3GB for user space. -DG David G. Lawrence President Download Technologies, Inc. - http://www.downloadtech.com - (866) 399 8500 TeraSolutions, Inc. - http://www.terasolutions.com - (888) 346 7175 The FreeBSD Project - http://www.freebsd.org Pave the road of life with opportunities. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: Kernel/Userland Mem-Space Tuning (1/3 on IA32)
David G. Lawrence wrote: sure about the exakt syntax but I know someone can change the half by half parity towards 1 to 3 in XP). I'm not sure whether FreeBSD divides kernel/userland address space this way, I know Linux and Windows does and on Windows we changed this (not yet on Linux and not yet on our FreeBSD machines (OS version 5.0, mostly FreeBSD 5.3-R or 5.4-PRERELEASE). Any help is appreciated. FreeBSD divides the 32bit virtual address space with 1GB for the kernel and 3GB for user processes. This can be changed with some kernel compile- time constants (primarily KVA_PAGES, however NKPT may also need to be increased if the kernel address space is increased). ... Dear David. Thank you very much. I assumed FreeBSD do the same like Linux, but don't obviously. I found a lot of tweaking kernel parameters, KVA_PAGES VM_KMEM_SIZE_SCALE VM_KMEM_SIZE_MAX VM_KMEM_SIZE The last three are not related to the address space division and you should not change those under normal circumstance. Reading some comments in sys/kern/kern_malloc.c make be a bit confused, I do not know much about kernel's interna. It is nice to hear that FreeBSD do a 1/3 division, I expected a 2/2 division like Linux does. So no need for anything changing. It's a 1:4 ratio. Sorry, I meant 1GB kernel, 3GB userland or 2GB kernel, 2GB userland, not the divisor or mathematical ratio, sorry for this unprecise. Can someone please explain NKPT? I'm simply curious, didn't found a satisfying answer via google, but a lot of source code with this in ... It's the number of page table pages that are assigned to the kernel address space. Each page maps 4MB, so 256 (the default) provides for 1GB of kernel virtual address space, leaving 3GB for user space. Many thanks, that helped a lot! Oliver ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
