Wei, Gang
2009-Aug-07 09:37 UTC
[Xen-devel] [PATCH] Enlarge default NR_CPUS to 64 for x86_64
By far a lot of systems are with more sockets (>=4), more cores (>=8), meanwhile with HyperThread, so enlarge the default NR_CPUS would easier the build for more threads systems. Jimmy ------------------------------------------------------------- Enlarge default NR_CPUS to 64 for x86_64. Signed-off-by: Wei Gang <gang.wei@intel.com> diff -r b9cdcf502aa3 xen/include/asm-x86/config.h --- a/xen/include/asm-x86/config.h Thu Aug 06 11:14:48 2009 +0100 +++ b/xen/include/asm-x86/config.h Fri Aug 07 14:54:06 2009 +0800 @@ -49,7 +49,11 @@ #ifdef MAX_PHYS_CPUS #define NR_CPUS MAX_PHYS_CPUS #else +#ifdef __i386__ #define NR_CPUS 32 +#else +#define NR_CPUS 64 +#endif #endif #ifdef __i386__ _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Keir Fraser
2009-Aug-07 09:52 UTC
Re: [Xen-devel] [PATCH] Enlarge default NR_CPUS to 64 for x86_64
Shall we just bump it for i386 too? -- Keir On 07/08/2009 10:37, "Wei, Gang" <gang.wei@intel.com> wrote:> By far a lot of systems are with more sockets (>=4), more cores (>=8), > meanwhile with HyperThread, so enlarge the default NR_CPUS would easier the > build for more threads systems. > > Jimmy > > ------------------------------------------------------------- > Enlarge default NR_CPUS to 64 for x86_64. > > Signed-off-by: Wei Gang <gang.wei@intel.com> > > diff -r b9cdcf502aa3 xen/include/asm-x86/config.h > --- a/xen/include/asm-x86/config.h Thu Aug 06 11:14:48 2009 +0100 > +++ b/xen/include/asm-x86/config.h Fri Aug 07 14:54:06 2009 +0800 > @@ -49,7 +49,11 @@ > #ifdef MAX_PHYS_CPUS > #define NR_CPUS MAX_PHYS_CPUS > #else > +#ifdef __i386__ > #define NR_CPUS 32 > +#else > +#define NR_CPUS 64 > +#endif > #endif > > #ifdef __i386_________________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Jan Beulich
2009-Aug-07 10:02 UTC
Re: [Xen-devel] [PATCH] Enlarge default NR_CPUS to 64 for x86_64
I think there''s little point in having both have the same limit. I''d rather question whether the limit shouldn''t be pushed up higher for x86-64. Jan>>> Keir Fraser <keir.fraser@eu.citrix.com> 07.08.09 11:52 >>>Shall we just bump it for i386 too? -- Keir On 07/08/2009 10:37, "Wei, Gang" <gang.wei@intel.com> wrote:> By far a lot of systems are with more sockets (>=4), more cores (>=8), > meanwhile with HyperThread, so enlarge the default NR_CPUS would easier the > build for more threads systems. > > Jimmy > > ------------------------------------------------------------- > Enlarge default NR_CPUS to 64 for x86_64. > > Signed-off-by: Wei Gang <gang.wei@intel.com> > > diff -r b9cdcf502aa3 xen/include/asm-x86/config.h > --- a/xen/include/asm-x86/config.h Thu Aug 06 11:14:48 2009 +0100 > +++ b/xen/include/asm-x86/config.h Fri Aug 07 14:54:06 2009 +0800 > @@ -49,7 +49,11 @@ > #ifdef MAX_PHYS_CPUS > #define NR_CPUS MAX_PHYS_CPUS > #else > +#ifdef __i386__ > #define NR_CPUS 32 > +#else > +#define NR_CPUS 64 > +#endif > #endif > > #ifdef __i386_________________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Keir Fraser
2009-Aug-07 10:11 UTC
Re: [Xen-devel] [PATCH] Enlarge default NR_CPUS to 64 for x86_64
Yes indeed. We could push to 128 no problem. I think Intel''s only concern is that 64 is as much as they test currently. -- Keir On 07/08/2009 11:02, "Jan Beulich" <JBeulich@novell.com> wrote:> I think there''s little point in having both have the same limit. I''d rather > question whether the limit shouldn''t be pushed up higher for x86-64. > > Jan > >>>> Keir Fraser <keir.fraser@eu.citrix.com> 07.08.09 11:52 >>> > Shall we just bump it for i386 too? > > -- Keir > > On 07/08/2009 10:37, "Wei, Gang" <gang.wei@intel.com> wrote: > >> By far a lot of systems are with more sockets (>=4), more cores (>=8), >> meanwhile with HyperThread, so enlarge the default NR_CPUS would easier the >> build for more threads systems. >> >> Jimmy >> >> ------------------------------------------------------------- >> Enlarge default NR_CPUS to 64 for x86_64. >> >> Signed-off-by: Wei Gang <gang.wei@intel.com> >> >> diff -r b9cdcf502aa3 xen/include/asm-x86/config.h >> --- a/xen/include/asm-x86/config.h Thu Aug 06 11:14:48 2009 +0100 >> +++ b/xen/include/asm-x86/config.h Fri Aug 07 14:54:06 2009 +0800 >> @@ -49,7 +49,11 @@ >> #ifdef MAX_PHYS_CPUS >> #define NR_CPUS MAX_PHYS_CPUS >> #else >> +#ifdef __i386__ >> #define NR_CPUS 32 >> +#else >> +#define NR_CPUS 64 >> +#endif >> #endif >> >> #ifdef __i386__ > > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel >_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Wei, Gang
2009-Aug-07 14:59 UTC
RE: [Xen-devel] [PATCH] Enlarge default NR_CPUS to 64 for x86_64
Not sure about whether we can raise it for i386 too. I am a little confused by
below lines in config.h:
#ifdef __i386__
#if NR_CPUS > 32
#error "Maximum of 32 physical processors supported by Xen on
x86_32"
#endif
/* Maximum number of virtual CPUs in multi-processor guests. */
#define MAX_VIRT_CPUS XEN_LEGACY_MAX_VCPUS
#endif
I don''t know why this compiling time error was put here for i386 yet.
Any body know it?
Jimmy
Keir Fraser wrote:> Shall we just bump it for i386 too?
>
> -- Keir
>
> On 07/08/2009 10:37, "Wei, Gang" <gang.wei@intel.com>
wrote:
>
>> By far a lot of systems are with more sockets (>=4), more cores
>> (>=8), meanwhile with HyperThread, so enlarge the default NR_CPUS
>> would easier the build for more threads systems.
>>
>> Jimmy
>>
>> -------------------------------------------------------------
>> Enlarge default NR_CPUS to 64 for x86_64.
>>
>> Signed-off-by: Wei Gang <gang.wei@intel.com>
>>
>> diff -r b9cdcf502aa3 xen/include/asm-x86/config.h
>> --- a/xen/include/asm-x86/config.h Thu Aug 06 11:14:48 2009 +0100
>> +++ b/xen/include/asm-x86/config.h Fri Aug 07 14:54:06 2009 +0800 @@
>> -49,7 +49,11 @@ #ifdef MAX_PHYS_CPUS
>> #define NR_CPUS MAX_PHYS_CPUS
>> #else
>> +#ifdef __i386__
>> #define NR_CPUS 32
>> +#else
>> +#define NR_CPUS 64
>> +#endif
>> #endif
>>
>> #ifdef __i386__
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Wei, Gang
2009-Aug-07 15:09 UTC
RE: [Xen-devel] [PATCH] Enlarge default NR_CPUS to 64 for x86_64
Yes, it is. We can push to 128 if there really are a lot of needs. The slightly side-effect is a little larger default memory footprint for hypervisor if not really need to support that much of pcpus. We can do it step by step. Jimmy Keir Fraser wrote:> Yes indeed. We could push to 128 no problem. I think Intel''s only > concern is that 64 is as much as they test currently. > > -- Keir > > On 07/08/2009 11:02, "Jan Beulich" <JBeulich@novell.com> wrote: > >> I think there''s little point in having both have the same limit. I''d >> rather question whether the limit shouldn''t be pushed up higher for >> x86-64. >> >> Jan >> >>>>> Keir Fraser <keir.fraser@eu.citrix.com> 07.08.09 11:52 >>> >> Shall we just bump it for i386 too? >> >> -- Keir >> >> On 07/08/2009 10:37, "Wei, Gang" <gang.wei@intel.com> wrote: >> >>> By far a lot of systems are with more sockets (>=4), more cores >>> (>=8), meanwhile with HyperThread, so enlarge the default NR_CPUS >>> would easier the build for more threads systems. >>> >>> Jimmy >>> >>> ------------------------------------------------------------- >>> Enlarge default NR_CPUS to 64 for x86_64. >>> >>> Signed-off-by: Wei Gang <gang.wei@intel.com> >>> >>> diff -r b9cdcf502aa3 xen/include/asm-x86/config.h >>> --- a/xen/include/asm-x86/config.h Thu Aug 06 11:14:48 2009 +0100 >>> +++ b/xen/include/asm-x86/config.h Fri Aug 07 14:54:06 2009 +0800 >>> @@ -49,7 +49,11 @@ #ifdef MAX_PHYS_CPUS >>> #define NR_CPUS MAX_PHYS_CPUS >>> #else >>> +#ifdef __i386__ >>> #define NR_CPUS 32 >>> +#else >>> +#define NR_CPUS 64 >>> +#endif >>> #endif >>> >>> #ifdef __i386__ >> >> >> >> _______________________________________________ >> Xen-devel mailing list >> Xen-devel@lists.xensource.com >> http://lists.xensource.com/xen-devel_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Keir Fraser
2009-Aug-07 16:18 UTC
Re: [Xen-devel] [PATCH] Enlarge default NR_CPUS to 64 for x86_64
On 07/08/2009 15:59, "Wei, Gang" <gang.wei@intel.com> wrote:> Not sure about whether we can raise it for i386 too. I am a little confused by > below lines in config.h: > > #ifdef __i386__ > #if NR_CPUS > 32 > #error "Maximum of 32 physical processors supported by Xen on x86_32" > #endif > /* Maximum number of virtual CPUs in multi-processor guests. */ > #define MAX_VIRT_CPUS XEN_LEGACY_MAX_VCPUS > #endif > > I don''t know why this compiling time error was put here for i386 yet. Any body > know it?I think it''s a hangover from when there was a cpumask_t inside struct page_info. That structure had to be fixed size for i386 to fit in the hypervisor''s virtual memory footprint. -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Dan Magenheimer
2009-Aug-08 21:46 UTC
RE: [Xen-devel] [PATCH] Enlarge default NR_CPUS to 64 for x86_64
> I think it''s a hangover from when there was a cpumask_t inside struct > page_info. That structure had to be fixed size for i386 to fit in the > hypervisor''s virtual memory footprint.FYI, xen/include/asm-x86/mm.h still #includes <xen/cpumask.h> and that include can be removed now (compile tested only).> -----Original Message----- > From: Keir Fraser [mailto:keir.fraser@eu.citrix.com] > Sent: Friday, August 07, 2009 10:18 AM > To: Wei, Gang; xen-devel@lists.xensource.com > Subject: Re: [Xen-devel] [PATCH] Enlarge default NR_CPUS to 64 for > x86_64 > > > On 07/08/2009 15:59, "Wei, Gang" <gang.wei@intel.com> wrote: > > > Not sure about whether we can raise it for i386 too. I am a > little confused by > > below lines in config.h: > > > > #ifdef __i386__ > > #if NR_CPUS > 32 > > #error "Maximum of 32 physical processors supported by > Xen on x86_32" > > #endif > > /* Maximum number of virtual CPUs in multi-processor guests. */ > > #define MAX_VIRT_CPUS XEN_LEGACY_MAX_VCPUS > > #endif > > > > I don''t know why this compiling time error was put here for > i386 yet. Any body > > know it? > > I think it''s a hangover from when there was a cpumask_t inside struct > page_info. That structure had to be fixed size for i386 to fit in the > hypervisor''s virtual memory footprint. > > -- Keir > > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel >_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Keir Fraser
2009-Aug-09 00:07 UTC
Re: [Xen-devel] [PATCH] Enlarge default NR_CPUS to 64 for x86_64
On 08/08/2009 22:46, "Dan Magenheimer" <dan.magenheimer@oracle.com> wrote:>> I think it''s a hangover from when there was a cpumask_t inside struct >> page_info. That structure had to be fixed size for i386 to fit in the >> hypervisor''s virtual memory footprint. > > FYI, xen/include/asm-x86/mm.h still #includes <xen/cpumask.h> > and that include can be removed now (compile tested only).Okay, I''ll remove it. Thanks, Keir _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel