On Sun, May 20, 2012 at 2:32 PM, Gilboa Davara gilboad@gmail.com wrote:
On Sun, May 20, 2012 at 4:07 AM, Josh Boyer jwboyer@redhat.com wrote:
On Sat, May 19, 2012 at 02:54:33PM +0200, Xose Vazquez Perez wrote:
- Tue Jan 17 2012 Dave Jones davej@redhat.com
- Rawhide builds now use MAXSMP on x86.
- For release builds, set x86-64 to support 64 CPUs.
If larger systems become widespread, we can increase in an update.
_today_
amd: 4sockets * 16cores = 64
Awesome. Got that covered still.
intel: 4sockets * 10cores * 2threads = 80
Which particular CPU/Motherboard combo is that, and how often do we see it in Fedora?
I'm not opposed to bumping it up to 128 or something, but I'm curious how many people are actually going to see benefits.
josh
At least in my case I did run Fedora 12-16 on 4S and 8S machines to test software scalability on (extreme) high-end hardware. Though, IMHO anyone that's crazy enough to run Fedora on a high-end 4S/8S machine is more than capable of rebuilding the kernel with CONFIG_NR_CPUS 256...
However, given the fact that x86_64 machines tend to be far less memory constrained than i686 machines, I doubt that raising the limit to 128 will cause too many issues. (Isn't NR_CPUS == 512 in el6?)
It's even higher these days:
grep NR_CPUS /boot/config-2.6.32-220.13.1.el6.x86_64 CONFIG_NR_CPUS=4096
I'm curious, has anyone measured what the memory overhead is of keeping NR_CPUS at 512? arch/x86/Kconfig says "This is purely to save memory - each supported CPU adds approximately eight kilobytes to the kernel image." If that's true, 512 cpus use 4MB, something I'm willing to live with on my 64bit servers.
Thanks,
Ruben