On Mon, May 21, 2012 at 1:25 AM, Xose Vazquez Perez
<xose.vazquez(a)gmail.com> wrote:
Ruben Kerkhof wrote:
> 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.
https://bugzilla.redhat.com/show_bug.cgi?id=219457
Keep in mind that this bug is ~5 y/o.
The last 5 years seen an explosion in both core count and standard
memory size in servers.
(While on the other hand, a lot of progress was made to reduce the
static allocations tied to NR_CPUS)
- Gilboa