[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] asm, x86: Set max CPUs to 512 instead of 256.
On Thu, Jan 22, 2015 at 05:04:12PM +0000, Andrew Cooper wrote: > On 22/01/15 16:52, Konrad Rzeszutek Wilk wrote: > > Contemporary servers sport now 480 CPUs or such. We should crank > > up the default amount of CPUs to a higher level to take advantage > > of this without having the distro to use 'max_phys_cpus' override. > > > > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> > > /me would really like to try something that big out, but I have not had > the opportunity yet to hit the 256 limit. > > I wonder which variables grow as a result of this change. We might want > to see about making more things dynamically allocated after reading the > apci tables, if we can. I am not sure if that is possible as there is a lot of DEFINE_PER_CPU which are cannot grow. The structures that grow are: struct cpumask struct kernel_param struct rangeset struct csched2_runqueue_data struct csched2_private struct rt_vcpu struct stopmachine_data struct free_ptr struct rcu_data struct physid_mask struct acpi_table_header struct calibration_rendezvous struct bug_frame (for fun see attached diff of pahole between 256 and 512 CPUs) > > ~Andrew > > > --- > > xen/include/asm-x86/config.h | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/xen/include/asm-x86/config.h b/xen/include/asm-x86/config.h > > index 2fbd68d..d450696 100644 > > --- a/xen/include/asm-x86/config.h > > +++ b/xen/include/asm-x86/config.h > > @@ -64,7 +64,7 @@ > > #ifdef MAX_PHYS_CPUS > > #define NR_CPUS MAX_PHYS_CPUS > > #else > > -#define NR_CPUS 256 > > +#define NR_CPUS 512 > > #endif > > > > /* Linkage for x86 */ > Attachment:
256vs512 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |