I was asked this question today and frankly, I didn't know the answer. So I thought I'd post it here....
If you don't need to access greater than 4GB RAM, is there any benefit to running the 64-bit version of CentOS vs the 32-bit one? That's assuming, of course, that the target machine utilizes a 64-bit capable processor. I hadn't seen any noticeable difference, but I haven't done any benchmarking either.
On a desktop machine, the 32-bit version seems preferable since there are closed source creature comfort apps that are not yet available in 64-bit land, correct?
Cheers,
On 4/16/07, chrism@imntv.com chrism@imntv.com wrote:
I was asked this question today and frankly, I didn't know the answer. So I thought I'd post it here....
If you don't need to access greater than 4GB RAM, is there any benefit to running the 64-bit version of CentOS vs the 32-bit one? That's assuming, of course, that the target machine utilizes a 64-bit capable processor. I hadn't seen any noticeable difference, but I haven't done any benchmarking either.
If you need to have processes larger than about 2GB you need to use 64 Bit versions of CentOS.
On a desktop machine, the 32-bit version seems preferable since there are closed source creature comfort apps that are not yet available in 64-bit land, correct?
Correct. While there is multilib to try and eleviate the pain of this.. I find it and the Debian chroot option both more painful than they should be.
chrism@imntv.com wrote:
If you don't need to access greater than 4GB RAM, is there any benefit to running the 64-bit version of CentOS vs the 32-bit one? That's assuming, of course, that the target machine utilizes a 64-bit capable processor. I hadn't seen any noticeable difference, but I haven't done any benchmarking either.
Using AMD chips, 64 bit mode is significantly faster than 32 bit mode (20 to 30 percent, depending on the code), due to the extra registers. I don't think this is the case for Intel chips. We run all our 64 bit desktops in 64 bit mode, and it's not too hard to get closed source 32 bit apps working.
There are also advantages for things like LVM+RAID+XFS, as I believe the stack size is larger, so it's less likely to crash.
Also, consider that not all of 4GB of RAM can be used in 32 bit mode. The kernel takes up a large chunk of 4GB (depending on kernel compilation options), so this limits the amount accessed by a single process.
Jeremy
--On Tuesday, April 17, 2007 12:55 PM +0100 Jeremy Sanders jss@ast.cam.ac.uk wrote:
Using AMD chips, 64 bit mode is significantly faster than 32 bit mode (20 to 30 percent, depending on the code), due to the extra registers. I don't think this is the case for Intel chips. We run all our 64 bit desktops in 64 bit mode, and it's not too hard to get closed source 32 bit apps working.
What kinds of issues do you run into, if any, getting 32 bit apps running on a 64 bit system?
For example, if I run 64 bit on my Venice-based game box, has anyone experience getting WoW to run in Cedega on that?
Kenneth Porter wrote:
What kinds of issues do you run into, if any, getting 32 bit apps running on a 64 bit system?
You may need to install a missing i386 library from the i386 distribution, which isn't supplied in the 64 bit dist. I have 32 and 64 bit distributions in the yum search path, which mostly works.
There are also a few scripts which assume things about where libraries are installed on the system.
Another issue are LD_PRELOAD and LD_LIBRARY_PATH tricks some programs or wrappers play.
For example, if I run 64 bit on my Venice-based game box, has anyone experience getting WoW to run in Cedega on that?
Not me. You can always install in a chroot environment if all else fails, but that's not much fun.
Jeremy
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chrism＠imntv.com -
Jeremy Sanders -
Kenneth Porter -
Stephen John Smoogen