On Thu, Apr 1, 2010 at 7:11 PM, Bruce Dubbs <[email protected]> wrote: > stosss wrote: >> If I compile the kernel with 64GB instead of 4GB on a 32-bit system >> that would allow me to use more than 4GB of physical RAM. Is my >> understanding correct? > > Maybe. It depends on your hardware. If it's supported in HW, the > kernel will do the equivalent of changing segments when it needs to > address memory outside of the current 32-bit logical address. Of course > this is not very efficient. > >> I have seen earlier that 64-bit does not improve performance very much >> over 32-bit. My main interest in building a 64-bit system is to be >> able to access more physical RAM. Will I be able to accomplish my >> objective with the 64GB switch instead of the 4GB switch in the kernel >> configuration? > > If you are using more than 4G at one time, you will see an improvement. > Personally, I have 2G on my main system and it almost never swaps, so > it wouldn't make much difference. > > OTOH, a large server may need it. For example: > > $ free > total used free shared buffers cached > Mem: 8068444 7991296 77148 0 40 4596364 > -/+ buffers/cache: 3394892 4673552 > Swap: 7812492 1190780 6621712 > >> Is there any other advantage to using a 64-bit system instead of a >> 32-bit system? > > It really depends on your application. If you are doing a simulation of > a complex fluid flow problem, it may be useful. If you are browsing the > web, probably not.
I like to run VirtualBox and I want to be able to run 2 to 4 VMs with at least a GB of RAM each allocated to them. So I am going to assume I would be better off running a 64-bit system with 8GB RAM maxed out on the mobo. I have one box currently that is ia64 HW. I am about to start my LFS 6.6 build and was trying to figure out if the potential problem which is probably mostly later in BLFS was something I wanted to tackle. I do believe it is because I have a compelling reason to have a system with a lot of power. -- If we can but prevent the government from wasting the labours of the people, under the pretence of taking care of them, they must become happy. - Thomas Jefferson -- http://linuxfromscratch.org/mailman/listinfo/lfs-support FAQ: http://www.linuxfromscratch.org/lfs/faq.html Unsubscribe: See the above information page
